Merge 3.3.3 release with Drano HTTP library at 3.3.0

Big delta was converting the new texture debugger support code
to the new library.  Viewer manifest should probably get an eyeball
before release.

1 files changed, 1225 insertions, 643 deletions

diff --git a/indra/newview/lltexturefetch.cpp b/indra/newview/lltexturefetch.cpp
index 7e6dfbc9d9..36b878d6f2 100755
--- a/indra/newview/lltexturefetch.cpp
+++ b/indra/newview/lltexturefetch.cpp
@@ -4,7 +4,7 @@
  *
  * $LicenseInfo:firstyear=2000&license=viewerlgpl$
  * Second Life Viewer Source Code
- * Copyright (C) 2010, Linden Research, Inc.
+ * Copyright (C) 2012, Linden Research, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -33,7 +33,6 @@
 
 #include "lltexturefetch.h"
 
-#include "llcurl.h"
 #include "lldir.h"
 #include "llhttpclient.h"
 #include "llhttpstatuscodes.h"
@@ -54,28 +53,213 @@
 #include "llworld.h"
 #include "llsdutil.h"
 #include "llstartup.h"
-#include "llviewerstats.h"
+#include "llsdserialize.h"
+
+#include "httprequest.h"
+#include "httphandler.h"
+#include "httpresponse.h"
+#include "bufferarray.h"
+#include "bufferstream.h"
 
 bool LLTextureFetchDebugger::sDebuggerEnabled = false ;
 LLStat LLTextureFetch::sCacheHitRate("texture_cache_hits", 128);
 LLStat LLTextureFetch::sCacheReadLatency("texture_cache_read_latency", 128);
 
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Introduction
+//
+// This is an attempt to document what's going on in here after-the-fact.
+// It's a sincere attempt to be accurate but there will be mistakes.
+//
+//
+// Purpose
+//
+// What is this module trying to do?  It accepts requests to load textures
+// at a given priority and discard level and notifies the caller when done
+// (successfully or not).  Additional constraints are:
+//
+// * Support a local texture cache.  Don't hit network when possible
+//   to avoid it.
+// * Use UDP or HTTP as directed or as fallback.  HTTP is tried when
+//   not disabled and a URL is available.  UDP when a URL isn't
+//   available or HTTP attempts fail.
+// * Asynchronous (using threads).  Main thread is not to be blocked or
+//   burdened.
+// * High concurrency.  Many requests need to be in-flight and at various
+//   stages of completion.
+// * Tolerate frequent re-prioritizations of requests.  Priority is
+//   a reflection of a camera's viewpoint and as that viewpoint changes,
+//   objects and textures become more and less relevant and that is
+//   expressed at this level by priority changes and request cancelations.
+//
+// The caller interfaces that fall out of the above and shape the
+// implementation are:
+// * createRequest - Load j2c image via UDP or HTTP at given discard level and priority
+// * deleteRequest - Request removal of prior request
+// * getRequestFinished - Test if request is finished returning data to caller
+// * updateRequestPriority - Change priority of existing request
+// * getFetchState - Retrieve progress on existing request
+//
+// Everything else in here is mostly plumbing, metrics and debug.
+//
+//
+// The Work Queue
+//
+// The two central classes are LLTextureFetch and LLTextureFetchWorker.
+// LLTextureFetch combines threading with a priority queue of work
+// requests.  The priority queue is sorted by a U32 priority derived
+// from the F32 priority in the APIs.  The *only* work request that
+// receives service time by this thread is the highest priority
+// request.  All others wait until it is complete or a dynamic priority
+// change has re-ordered work.
+//
+// LLTextureFetchWorker implements the work request and is 1:1 with
+// texture fetch requests.  Embedded in each is a state machine that
+// walks it through the cache, HTTP, UDP, image decode and retry
+// steps of texture acquisition.
+//
+//
+// Threads
+//
+// Several threads are actively invoking code in this module.  They
+// include:
+//
+// 1.  Tmain    Main thread of execution
+// 2.  Ttf      LLTextureFetch's worker thread provided by LLQueuedThread
+// 3.  Tcurl    LLCurl's worker thread (should disappear over time)
+// 4.  Ttc      LLTextureCache's worker thread
+// 5.  Tid      Image decoder's worker thread
+// 6.  Thl      HTTP library's worker thread
+//
+//
+// Mutexes/Condition Variables
+//
+// 1.  Mt       Mutex defined for LLThread's condition variable (base class of
+//              LLTextureFetch)
+// 2.  Ct       Condition variable for LLThread and used by lock/unlockData().
+// 3.  Mwtd     Special LLWorkerThread mutex used for request deletion
+//              operations (base class of LLTextureFetch)
+// 4.  Mfq      LLTextureFetch's mutex covering request and command queue
+//              data.
+// 5.  Mfnq     LLTextureFetch's mutex covering udp and http request
+//              queue data.
+// 6.  Mwc      Mutex covering LLWorkerClass's members (base class of
+//              LLTextureFetchWorker).  One per request.
+// 7.  Mw       LLTextureFetchWorker's mutex.  One per request.
+//
+//
+// Lock Ordering Rules
+//
+// Not an exhaustive list but shows the order of lock acquisition
+// needed to prevent deadlocks.  'A < B' means acquire 'A' before
+// acquiring 'B'.
+//
+// 1.    Mw < Mfnq
+// (there are many more...)
+//
+//
+// Method and Member Definitions
+//
+// With the above, we'll try to document what threads can call what
+// methods (using T* for any), what locks must be held on entry and
+// are taken out during execution and what data is covered by which
+// lock (if any).  This latter category will be especially prone to
+// error so be skeptical.
+//
+// A line like:  "// Locks:  M<xxx>" indicates a method that must
+// be invoked by a caller holding the 'M<xxx>' lock.  Similarly,
+// "// Threads:  T<xxx>" means that a caller should be running in
+// the indicated thread.
+//
+// For data members, a trailing comment like "// M<xxx>" means that
+// the data member is covered by the specified lock.  Absence of a
+// comment can mean the member is unlocked or that I didn't bother
+// to do the archaeology.  In the case of LLTextureFetchWorker,
+// most data members added by the leaf class are actually covered
+// by the Mw lock.  You may also see "// T<xxx>" which means that
+// the member's usage is restricted to one thread (except for
+// perhaps construction and destruction) and so explicit locking
+// isn't used.
+//
+// In code, a trailing comment like "// [-+]M<xxx>" indicates a
+// lock acquision or release point.
+//
+//
+// Worker Lifecycle
+//
+// The threading and responder model makes it very likely that
+// other components are holding on to a pointer to a worker request.
+// So, uncoordinated deletions of requests is a guarantee of memory
+// corruption in a short time.  So destroying a request involves
+// invocations's of LLQueuedThread/LLWorkerThread's abort/stop
+// logic that removes workers and puts them ona delete queue for
+// 2-phase destruction.  That second phase is deferrable by calls
+// to deleteOK() which only allow final destruction (via dtor)
+// once deleteOK has determined that the request is in a safe
+// state.
+//
+//
+// Worker State Machine
+//
+// (ASCII art needed)
+//
+//
+// Priority Scheme
+//
+// [PRIORITY_LOW, PRIORITY_NORMAL)   - for WAIT_HTTP_RESOURCE state
+//									   and other wait states
+// [PRIORITY_HIGH, PRIORITY_URGENT)  - External event delivered,
+//                                     rapidly transitioning through states,
+//                                     no waiting allowed
+//
+// By itself, the above work queue model would fail the concurrency
+// and liveness requirements of the interface.  A high priority
+// request could find itself on the head and stalled for external
+// reasons (see VWR-28996).  So a few additional constraints are
+// required to keep things running:
+// * Anything that can make forward progress must be kept at a
+//   higher priority than anything that can't.
+// * On completion of external events, the associated request
+//   needs to be elevated beyond the normal range to handle
+//   any data delivery and release any external resource.
+//
+// This effort is made to keep higher-priority entities moving
+// forward in their state machines at every possible step of
+// processing.  It's not entirely proven that this produces the
+// experiencial benefits promised.
+//
+
+//////////////////////////////////////////////////////////////////////////////
+
+// Tuning/Parameterization Constants
+
+static const S32 HTTP_REQUESTS_IN_QUEUE_HIGH_WATER = 40;		// Maximum requests to have active in HTTP
+static const S32 HTTP_REQUESTS_IN_QUEUE_LOW_WATER = 20;			// Active level at which to refill
+
+
 //////////////////////////////////////////////////////////////////////////////
-class LLTextureFetchWorker : public LLWorkerClass
+
+class LLTextureFetchWorker : public LLWorkerClass, public LLCore::HttpHandler
+
 {
 	friend class LLTextureFetch;
-	friend class HTTPGetResponder;
 	friend class LLTextureFetchDebugger;
 	
 private:
 	class CacheReadResponder : public LLTextureCache::ReadResponder
 	{
 	public:
+
+		// Threads:  Ttf
 		CacheReadResponder(LLTextureFetch* fetcher, const LLUUID& id, LLImageFormatted* image)
 			: mFetcher(fetcher), mID(id)
 		{
 			setImage(image);
 		}
+
+		// Threads:  Ttc
 		virtual void completed(bool success)
 		{
 			LLTextureFetchWorker* worker = mFetcher->getWorker(mID);
@@ -92,10 +276,14 @@ private:
 	class CacheWriteResponder : public LLTextureCache::WriteResponder
 	{
 	public:
+
+		// Threads:  Ttf
 		CacheWriteResponder(LLTextureFetch* fetcher, const LLUUID& id)
 			: mFetcher(fetcher), mID(id)
 		{
 		}
+
+		// Threads:  Ttc
 		virtual void completed(bool success)
 		{
 			LLTextureFetchWorker* worker = mFetcher->getWorker(mID);
@@ -112,10 +300,14 @@ private:
 	class DecodeResponder : public LLImageDecodeThread::Responder
 	{
 	public:
+
+		// Threads:  Ttf
 		DecodeResponder(LLTextureFetch* fetcher, const LLUUID& id, LLTextureFetchWorker* worker)
 			: mFetcher(fetcher), mID(id), mWorker(worker)
 		{
 		}
+
+		// Threads:  Tid
 		virtual void completed(bool success, LLImageRaw* raw, LLImageRaw* aux)
 		{
 			LLTextureFetchWorker* worker = mFetcher->getWorker(mID);
@@ -148,22 +340,35 @@ private:
 	};
 	
 public:
+
+	// Threads:  Ttf
 	/*virtual*/ bool doWork(S32 param); // Called from LLWorkerThread::processRequest()
+
+	// Threads:  Ttf
 	/*virtual*/ void finishWork(S32 param, bool completed); // called from finishRequest() (WORK THREAD)
-	/*virtual*/ bool deleteOK(); // called from update() (WORK THREAD)
+
+	// Threads:  Tmain
+	/*virtual*/ bool deleteOK(); // called from update()
 
 	~LLTextureFetchWorker();
-	// void relese() { --mActiveCount; }
 
-	S32 callbackHttpGet(const LLChannelDescriptors& channels,
-						 const LLIOPipe::buffer_ptr_t& buffer,
-						 bool partial, bool success);
+	// Threads:  Ttf
+	// Locks:  Mw
+	S32 callbackHttpGet(LLCore::HttpResponse * response,
+						bool partial, bool success);
+
+	// Threads:  Ttc
 	void callbackCacheRead(bool success, LLImageFormatted* image,
 						   S32 imagesize, BOOL islocal);
+
+	// Threads:  Ttc
 	void callbackCacheWrite(bool success);
+
+	// Threads:  Tid
 	void callbackDecoded(bool success, LLImageRaw* raw, LLImageRaw* aux);
 	
-	void setGetStatus(U32 status, const std::string& reason)
+	// Threads:  T*
+	void setGetStatus(LLCore::HttpStatus status, const std::string& reason)
 	{
 		LLMutexLock lock(&mWorkMutex);
 
@@ -175,33 +380,86 @@ public:
 	bool getCanUseHTTP() const { return mCanUseHTTP; }
 
 	LLTextureFetch & getFetcher() { return *mFetcher; }
+
+	// Inherited from LLCore::HttpHandler
+	// Threads:  Ttf
+	virtual void onCompleted(LLCore::HttpHandle handle, LLCore::HttpResponse * response);
 	
 protected:
 	LLTextureFetchWorker(LLTextureFetch* fetcher, const std::string& url, const LLUUID& id, const LLHost& host,
 						 F32 priority, S32 discard, S32 size);
 
 private:
+
+	// Threads:  Tmain
 	/*virtual*/ void startWork(S32 param); // called from addWork() (MAIN THREAD)
+
+	// Threads:  Tmain
 	/*virtual*/ void endWork(S32 param, bool aborted); // called from doWork() (MAIN THREAD)
 
+	// Locks:  Mw
 	void resetFormattedData();
 	
+	// Locks:  Mw
 	void setImagePriority(F32 priority);
+
+	// Locks:  Mw (ctor invokes without lock)
 	void setDesiredDiscard(S32 discard, S32 size);
+
+    // Threads:  T*
+	// Locks:  Mw
 	bool insertPacket(S32 index, U8* data, S32 size);
+
+	// Locks:  Mw
 	void clearPackets();
+
+	// Locks:  Mw
 	void setupPacketData();
+
+	// Locks:  Mw (ctor invokes without lock)
 	U32 calcWorkPriority();
+	
+	// Locks:  Mw
 	void removeFromCache();
+
+	// Threads:  Ttf
+	// Locks:  Mw
 	bool processSimulatorPackets();
+
+	// Threads:  Ttf
 	bool writeToCacheComplete();
 	
+	// Threads:  Ttf
+	void recordTextureStart(bool is_http);
+
+	// Threads:  Ttf
+	void recordTextureDone(bool is_http);
+
 	void lockWorkMutex() { mWorkMutex.lock(); }
 	void unlockWorkMutex() { mWorkMutex.unlock(); }
 
+	// Locks:  Mw
+	void acquireHttpSemaphore()
+		{
+			llassert(! mHttpHasResource);
+			mHttpHasResource = true;
+			--mFetcher->mHttpSemaphore;
+		}
+
+	// Locks:  Mw
+	void releaseHttpSemaphore()
+		{
+			llassert(mHttpHasResource);
+			mHttpHasResource = false;
+			++mFetcher->mHttpSemaphore;
+		}
+	
 private:
 	enum e_state // mState
 	{
+		// *NOTE:  Do not change the order/value of state variables, some code
+		// depends upon specific ordering/adjacency.
+		
 		// NOTE: Affects LLTextureBar::draw in lltextureview.cpp (debug hack)
 		INVALID = 0,
 		INIT,
@@ -209,8 +467,10 @@ private:
 		CACHE_POST,
 		LOAD_FROM_NETWORK,
 		LOAD_FROM_SIMULATOR,
-		SEND_HTTP_REQ,
-		WAIT_HTTP_REQ,
+		WAIT_HTTP_RESOURCE,				// Waiting for HTTP resources
+		WAIT_HTTP_RESOURCE2,			// Waiting for HTTP resources
+		SEND_HTTP_REQ,					// Commit to sending as HTTP
+		WAIT_HTTP_REQ,					// Request sent, wait for completion
 		DECODE_IMAGE,
 		DECODE_IMAGE_UPDATE,
 		WRITE_TO_CACHE,
@@ -254,9 +514,8 @@ private:
 	F32				mCacheReadTime;
 	LLTextureCache::handle_t mCacheReadHandle;
 	LLTextureCache::handle_t mCacheWriteHandle;
-	U8* mBuffer;
-	S32 mBufferSize;
 	S32 mRequestedSize;
+	S32 mRequestedOffset;
 	S32 mDesiredSize;
 	S32 mFileSize;
 	S32 mCachedSize;	
@@ -271,10 +530,9 @@ private:
 	BOOL mInCache;
 	bool mCanUseHTTP ;
 	bool mCanUseNET ; //can get from asset server.
-	S32 mHTTPFailCount;
 	S32 mRetryAttempt;
 	S32 mActiveCount;
-	U32 mGetStatus;
+	LLCore::HttpStatus mGetStatus;
 	std::string mGetReason;
 	
 	// Work Data
@@ -294,105 +552,19 @@ private:
 	U8 mImageCodec;
 
 	LLViewerAssetStats::duration_t mMetricsStartTime;
-};
-
-//////////////////////////////////////////////////////////////////////////////
-
-class HTTPGetResponder : public LLCurl::Responder
-{
-	LOG_CLASS(HTTPGetResponder);
-public:
-	HTTPGetResponder(LLTextureFetch* fetcher, const LLUUID& id, U64 startTime, S32 requestedSize, U32 offset, bool redir)
-		: mFetcher(fetcher), mID(id), mStartTime(startTime), mRequestedSize(requestedSize), mOffset(offset), mFollowRedir(redir)
-	{
-	}
-	~HTTPGetResponder()
-	{
-	}
-
-	virtual void completedRaw(U32 status, const std::string& reason,
-							  const LLChannelDescriptors& channels,
-							  const LLIOPipe::buffer_ptr_t& buffer)
-	{
-		static LLCachedControl<bool> log_to_viewer_log(gSavedSettings,"LogTextureDownloadsToViewerLog");
-		static LLCachedControl<bool> log_to_sim(gSavedSettings,"LogTextureDownloadsToSimulator");
-		static LLCachedControl<bool> log_texture_traffic(gSavedSettings,"LogTextureNetworkTraffic") ;
-
-		if (log_to_viewer_log || log_to_sim)
-		{
-			mFetcher->mTextureInfo.setRequestStartTime(mID, mStartTime);
-			U64 timeNow = LLTimer::getTotalTime();
-			mFetcher->mTextureInfo.setRequestType(mID, LLTextureInfoDetails::REQUEST_TYPE_HTTP);
-			mFetcher->mTextureInfo.setRequestSize(mID, mRequestedSize);
-			mFetcher->mTextureInfo.setRequestOffset(mID, mOffset);
-			mFetcher->mTextureInfo.setRequestCompleteTimeAndLog(mID, timeNow);
-		}
-
-		lldebugs << "HTTP COMPLETE: " << mID << llendl;
-		LLTextureFetchWorker* worker = mFetcher->getWorker(mID);
-		if (worker)
-		{
-			bool success = false;
-			bool partial = false;
-			if (HTTP_OK <= status &&  status < HTTP_MULTIPLE_CHOICES)
-			{
-				success = true;
-				if (HTTP_PARTIAL_CONTENT == status) // partial information
-				{
-					partial = true;
-				}
-			}
-
-			if (!success)
-			{
-				worker->setGetStatus(status, reason);
-// 				llwarns << "CURL GET FAILED, status:" << status << " reason:" << reason << llendl;
-			}
-			
-			S32 data_size = worker->callbackHttpGet(channels, buffer, partial, success);
-			
-			if(log_texture_traffic && data_size > 0)
-			{
-				LLViewerTexture* tex = LLViewerTextureManager::findTexture(mID) ;
-				if(tex)
-				{
-					gTotalTextureBytesPerBoostLevel[tex->getBoostLevel()] += data_size ;
-				}
-			}
-
-			mFetcher->removeFromHTTPQueue(mID, data_size);
-
-			if (worker->mMetricsStartTime)
-			{
-				LLViewerAssetStatsFF::record_response_thread1(LLViewerAssetType::AT_TEXTURE,
-															  true,
-															  LLImageBase::TYPE_AVATAR_BAKE == worker->mType,
-															  LLViewerAssetStatsFF::get_timestamp() - worker->mMetricsStartTime);
-				worker->mMetricsStartTime = 0;
-			}
-			LLViewerAssetStatsFF::record_dequeue_thread1(LLViewerAssetType::AT_TEXTURE,
-														 true,
-														 LLImageBase::TYPE_AVATAR_BAKE == worker->mType);
-		}
-		else
-		{
-			mFetcher->removeFromHTTPQueue(mID);
- 			llwarns << "Worker not found: " << mID << llendl;
-		}
-	}
 
-	virtual bool followRedir()
-	{
-		return mFollowRedir;
-	}
-	
-private:
-	LLTextureFetch* mFetcher;
-	LLUUID mID;
-	U64 mStartTime;
-	S32 mRequestedSize;
-	U32 mOffset;
-	bool mFollowRedir;
+	LLCore::HttpHandle		mHttpHandle;				// Handle of any active request
+	LLCore::BufferArray	*	mHttpBufferArray;			// Refcounted pointer to response data 
+	int						mHttpPolicyClass;
+	bool					mHttpActive;				// Active request to http library
+	unsigned int			mHttpReplySize;
+	unsigned int			mHttpReplyOffset;
+	bool					mHttpHasResource;			// Counts against Fetcher's mHttpSemaphore
+
+	// State history
+	U32 mCacheReadCount;
+	U32 mCacheWriteCount;
+	U32 mResourceWaitCount;
 };
 
 //////////////////////////////////////////////////////////////////////////////
@@ -628,13 +800,15 @@ const char* LLTextureFetchWorker::sStateDescs[] = {
 	"CACHE_POST",
 	"LOAD_FROM_NETWORK",
 	"LOAD_FROM_SIMULATOR",
+	"WAIT_HTTP_RESOURCE",
+	"WAIT_HTTP_RESOURCE2",
 	"SEND_HTTP_REQ",
 	"WAIT_HTTP_REQ",
 	"DECODE_IMAGE",
 	"DECODE_IMAGE_UPDATE",
 	"WRITE_TO_CACHE",
 	"WAIT_ON_WRITE",
-	"DONE",
+	"DONE"
 };
 
 // static
@@ -650,6 +824,7 @@ LLTextureFetchWorker::LLTextureFetchWorker(LLTextureFetch* fetcher,
 										   S32 discard,			// Desired discard
 										   S32 size)			// Desired size
 	: LLWorkerClass(fetcher, "TextureFetch"),
+	  LLCore::HttpHandler(),
 	  mState(INIT),
 	  mWriteToCacheState(NOT_WRITE),
 	  mFetcher(fetcher),
@@ -667,9 +842,8 @@ LLTextureFetchWorker::LLTextureFetchWorker(LLTextureFetch* fetcher,
 	  mCacheReadTime(0.f),
 	  mCacheReadHandle(LLTextureCache::nullHandle()),
 	  mCacheWriteHandle(LLTextureCache::nullHandle()),
-	  mBuffer(NULL),
-	  mBufferSize(0),
 	  mRequestedSize(0),
+	  mRequestedOffset(0),
 	  mDesiredSize(TEXTURE_CACHE_ENTRY_SIZE),
 	  mFileSize(0),
 	  mCachedSize(0),
@@ -683,16 +857,24 @@ LLTextureFetchWorker::LLTextureFetchWorker(LLTextureFetch* fetcher,
 	  mInLocalCache(FALSE),
 	  mInCache(FALSE),
 	  mCanUseHTTP(true),
-	  mHTTPFailCount(0),
 	  mRetryAttempt(0),
 	  mActiveCount(0),
-	  mGetStatus(0),
 	  mWorkMutex(NULL),
 	  mFirstPacket(0),
 	  mLastPacket(-1),
 	  mTotalPackets(0),
 	  mImageCodec(IMG_CODEC_INVALID),
-	  mMetricsStartTime(0)
+	  mMetricsStartTime(0),
+	  mHttpHandle(LLCORE_HTTP_HANDLE_INVALID),
+	  mHttpBufferArray(NULL),
+	  mHttpPolicyClass(LLCore::HttpRequest::DEFAULT_POLICY_ID),
+	  mHttpActive(false),
+	  mHttpReplySize(0U),
+	  mHttpReplyOffset(0U),
+	  mHttpHasResource(false),
+	  mCacheReadCount(0U),
+	  mCacheWriteCount(0U),
+	  mResourceWaitCount(0U)
 {
 	mCanUseNET = mUrl.empty() ;
 
@@ -714,7 +896,17 @@ LLTextureFetchWorker::~LLTextureFetchWorker()
 // 			<< " Requested=" << mRequestedDiscard
 // 			<< " Desired=" << mDesiredDiscard << llendl;
 	llassert_always(!haveWork());
-	lockWorkMutex();
+
+	lockWorkMutex();													// +Mw (should be useless)
+	if (mHttpHasResource)
+	{
+		releaseHttpSemaphore();
+	}
+	if (mHttpActive)
+	{
+		// Issue a cancel on a live request...
+		mFetcher->getHttpRequest().requestCancel(mHttpHandle, NULL);
+	}
 	if (mCacheReadHandle != LLTextureCache::nullHandle() && mFetcher->mTextureCache)
 	{
 		mFetcher->mTextureCache->readComplete(mCacheReadHandle, true);
@@ -725,10 +917,18 @@ LLTextureFetchWorker::~LLTextureFetchWorker()
 	}
 	mFormattedImage = NULL;
 	clearPackets();
-	unlockWorkMutex();
+	if (mHttpBufferArray)
+	{
+		mHttpBufferArray->release();
+		mHttpBufferArray = NULL;
+	}
+	unlockWorkMutex();													// -Mw
 	mFetcher->removeFromHTTPQueue(mID);
+	mFetcher->removeHttpWaiter(mID);
+	mFetcher->updateStateStats(mCacheReadCount, mCacheWriteCount, mResourceWaitCount);
 }
 
+// Locks:  Mw
 void LLTextureFetchWorker::clearPackets()
 {
 	for_each(mPackets.begin(), mPackets.end(), DeletePointer());
@@ -738,6 +938,7 @@ void LLTextureFetchWorker::clearPackets()
 	mFirstPacket = 0;
 }
 
+// Locks:  Mw
 void LLTextureFetchWorker::setupPacketData()
 {
 	S32 data_size = 0;
@@ -770,6 +971,7 @@ void LLTextureFetchWorker::setupPacketData()
 	}
 }
 
+// Locks:  Mw (ctor invokes without lock)
 U32 LLTextureFetchWorker::calcWorkPriority()
 {
  	//llassert_always(mImagePriority >= 0 && mImagePriority <= LLViewerFetchedTexture::maxDecodePriority());
@@ -779,7 +981,7 @@ U32 LLTextureFetchWorker::calcWorkPriority()
 	return mWorkPriority;
 }
 
-// mWorkMutex is locked
+// Locks:  Mw (ctor invokes without lock)
 void LLTextureFetchWorker::setDesiredDiscard(S32 discard, S32 size)
 {
 	bool prioritize = false;
@@ -815,6 +1017,7 @@ void LLTextureFetchWorker::setDesiredDiscard(S32 discard, S32 size)
 	}
 }
 
+// Locks:  Mw
 void LLTextureFetchWorker::setImagePriority(F32 priority)
 {
 // 	llassert_always(priority >= 0 && priority <= LLViewerTexture::maxDecodePriority());
@@ -828,11 +1031,14 @@ void LLTextureFetchWorker::setImagePriority(F32 priority)
 	}
 }
 
+// Locks:  Mw
 void LLTextureFetchWorker::resetFormattedData()
 {
-	FREE_MEM(LLImageBase::getPrivatePool(), mBuffer);
-	mBuffer = NULL;
-	mBufferSize = 0;
+	if (mHttpBufferArray)
+	{
+		mHttpBufferArray->release();
+		mHttpBufferArray = NULL;
+	}
 	if (mFormattedImage.notNull())
 	{
 		mFormattedImage->deleteData();
@@ -840,20 +1046,25 @@ void LLTextureFetchWorker::resetFormattedData()
 	mHaveAllData = FALSE;
 }
 
-// Called from MAIN thread
+// Threads:  Tmain
 void LLTextureFetchWorker::startWork(S32 param)
 {
 	llassert(mFormattedImage.isNull());
 }
 
-#include "llviewertexturelist.h" // debug
-
-// Called from LLWorkerThread::processRequest()
+// Threads:  Ttf
 bool LLTextureFetchWorker::doWork(S32 param)
 {
 	static const F32 FETCHING_TIMEOUT = 120.f;//seconds
-
-	LLMutexLock lock(&mWorkMutex);
+	
+	static const LLCore::HttpStatus http_not_found(HTTP_NOT_FOUND);						// 404
+	static const LLCore::HttpStatus http_service_unavail(HTTP_SERVICE_UNAVAILABLE);		// 503
+	static const LLCore::HttpStatus http_not_sat(HTTP_REQUESTED_RANGE_NOT_SATISFIABLE);	// 416;
+	
+	// Release waiters while we aren't holding the Mw lock.
+	mFetcher->releaseHttpWaiters();
+	
+	LLMutexLock lock(&mWorkMutex);										// +Mw
 
 	if ((mFetcher->isQuitting() || getFlags(LLWorkerClass::WCF_DELETE_REQUESTED)))
 	{
@@ -897,15 +1108,18 @@ bool LLTextureFetchWorker::doWork(S32 param)
 		mLoadedDiscard = -1;
 		mDecodedDiscard = -1;
 		mRequestedSize = 0;
+		mRequestedOffset = 0;
 		mFileSize = 0;
 		mCachedSize = 0;
 		mLoaded = FALSE;
 		mSentRequest = UNSENT;
 		mDecoded  = FALSE;
 		mWritten  = FALSE;
-		FREE_MEM(LLImageBase::getPrivatePool(), mBuffer);
-		mBuffer = NULL;
-		mBufferSize = 0;
+		if (mHttpBufferArray)
+		{
+			mHttpBufferArray->release();
+			mHttpBufferArray = NULL;
+		}
 		mHaveAllData = FALSE;
 		clearPackets(); // TODO: Shouldn't be necessary
 		mCacheReadHandle = LLTextureCache::nullHandle();
@@ -938,6 +1152,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 				setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority); // Set priority first since Responder may change it
 
 				// read file from local disk
+				++mCacheReadCount;
 				std::string filename = mUrl.substr(7, std::string::npos);
 				CacheReadResponder* responder = new CacheReadResponder(mFetcher, mID, mFormattedImage);
 				mCacheReadHandle = mFetcher->mTextureCache->readFromCache(filename, mID, cache_priority,
@@ -948,6 +1163,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 			{
 				setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority); // Set priority first since Responder may change it
 
+				++mCacheReadCount;
 				CacheReadResponder* responder = new CacheReadResponder(mFetcher, mID, mFormattedImage);
 				mCacheReadHandle = mFetcher->mTextureCache->readFromCache(mID, cache_priority,
 																		  offset, size, responder);
@@ -961,7 +1177,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 					llwarns << "Unknown URL Type: " << mUrl << llendl;
 				}
 				setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
-				mState = SEND_HTTP_REQ;
+				mState = WAIT_HTTP_RESOURCE;
 			}
 			else
 			{
@@ -1060,7 +1276,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 		}
 		if (mCanUseHTTP && !mUrl.empty())
 		{
-			mState = LLTextureFetchWorker::SEND_HTTP_REQ;
+			mState = WAIT_HTTP_RESOURCE;
 			setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
 			if(mWriteToCacheState != NOT_WRITE)
 			{
@@ -1077,13 +1293,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 			mRequestedDiscard = mDesiredDiscard;
 			mSentRequest = QUEUED;
 			mFetcher->addToNetworkQueue(this);
-			if (! mMetricsStartTime)
-			{
-				mMetricsStartTime = LLViewerAssetStatsFF::get_timestamp();
-			}
-			LLViewerAssetStatsFF::record_enqueue_thread1(LLViewerAssetType::AT_TEXTURE,
-														 false,
-														 LLImageBase::TYPE_AVATAR_BAKE == mType);
+			recordTextureStart(false);
 			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
 			
 			return false;
@@ -1094,12 +1304,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 			//llassert_always(mFetcher->mNetworkQueue.find(mID) != mFetcher->mNetworkQueue.end());
 			// Make certain this is in the network queue
 			//mFetcher->addToNetworkQueue(this);
-			//if (! mMetricsStartTime)
-			//{
-			//   mMetricsStartTime = LLViewerAssetStatsFF::get_timestamp();
-			//}
-			//LLViewerAssetStatsFF::record_enqueue_thread1(LLViewerAssetType::AT_TEXTURE, false,
-			//                                             LLImageBase::TYPE_AVATAR_BAKE == mType);
+			//recordTextureStart(false);
 			//setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
 			return false;
 		}
@@ -1124,119 +1329,116 @@ bool LLTextureFetchWorker::doWork(S32 param)
 			setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
 			mState = DECODE_IMAGE;
 			mWriteToCacheState = SHOULD_WRITE;
-
-			if (mMetricsStartTime)
-			{
-				LLViewerAssetStatsFF::record_response_thread1(LLViewerAssetType::AT_TEXTURE,
-															  false,
-															  LLImageBase::TYPE_AVATAR_BAKE == mType,
-															  LLViewerAssetStatsFF::get_timestamp() - mMetricsStartTime);
-				mMetricsStartTime = 0;
-			}
-			LLViewerAssetStatsFF::record_dequeue_thread1(LLViewerAssetType::AT_TEXTURE,
-														 false,
-														 LLImageBase::TYPE_AVATAR_BAKE == mType);
+			recordTextureDone(false);
 		}
 		else
 		{
 			mFetcher->addToNetworkQueue(this); // failsafe
-			if (! mMetricsStartTime)
-			{
-				mMetricsStartTime = LLViewerAssetStatsFF::get_timestamp();
-			}
-			LLViewerAssetStatsFF::record_enqueue_thread1(LLViewerAssetType::AT_TEXTURE,
-														 false,
-														 LLImageBase::TYPE_AVATAR_BAKE == mType);
 			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
+			recordTextureStart(false);
+		}
+		return false;
+	}
+	
+	if (mState == WAIT_HTTP_RESOURCE)
+	{
+		// NOTE:
+		// control the number of the http requests issued for:
+		// 1, not openning too many file descriptors at the same time;
+		// 2, control the traffic of http so udp gets bandwidth.
+		//
+		// If it looks like we're busy, keep this request here.
+		// Otherwise, advance into the HTTP states.
+		if (mFetcher->mHttpSemaphore <= 0 || mFetcher->getHttpWaitersCount())
+		{
+			mState = WAIT_HTTP_RESOURCE2;
+			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
+			mFetcher->addHttpWaiter(this->mID);
+			++mResourceWaitCount;
+			return false;
 		}
+		mState = SEND_HTTP_REQ;
+		acquireHttpSemaphore();
+	}
+
+	if (mState == WAIT_HTTP_RESOURCE2)
+	{
+		// Just idle it if we make it to the head...
 		return false;
 	}
 	
 	if (mState == SEND_HTTP_REQ)
 	{
-		if(mCanUseHTTP)
+		if (! mCanUseHTTP)
 		{
-			//NOTE:
-			//control the number of the http requests issued for:
-			//1, not openning too many file descriptors at the same time;
-			//2, control the traffic of http so udp gets bandwidth.
-			//
-			static const S32 MAX_NUM_OF_HTTP_REQUESTS_IN_QUEUE = 8 ;
-			if(mFetcher->getNumHTTPRequests() > MAX_NUM_OF_HTTP_REQUESTS_IN_QUEUE)
-			{
-				return false ; //wait.
-			}
+			releaseHttpSemaphore();
+			return true; // abort
+		}
 
-			mFetcher->removeFromNetworkQueue(this, false);
+		mFetcher->removeFromNetworkQueue(this, false);
 			
-			S32 cur_size = 0;
-			if (mFormattedImage.notNull())
+		S32 cur_size = 0;
+		if (mFormattedImage.notNull())
+		{
+			cur_size = mFormattedImage->getDataSize(); // amount of data we already have
+			if (mFormattedImage->getDiscardLevel() == 0)
 			{
-				cur_size = mFormattedImage->getDataSize(); // amount of data we already have
-				if (mFormattedImage->getDiscardLevel() == 0)
+				if (cur_size > 0)
 				{
-					if(cur_size > 0)
-					{
-						// We already have all the data, just decode it
-						mLoadedDiscard = mFormattedImage->getDiscardLevel();
-						mState = DECODE_IMAGE;
-						return false;
-					}
-					else
-					{
-						return true ; //abort.
-					}
+					// We already have all the data, just decode it
+					mLoadedDiscard = mFormattedImage->getDiscardLevel();
+					mState = DECODE_IMAGE;
+					releaseHttpSemaphore();
+					return false;
 				}
-			}
-			mRequestedSize = mDesiredSize;
-			mRequestedDiscard = mDesiredDiscard;
-			mRequestedSize -= cur_size;
-			S32 offset = cur_size;
-			mBufferSize = cur_size; // This will get modified by callbackHttpGet()
-			
-			bool res = false;
-			if (!mUrl.empty())
-			{
-				mRequestedTimer.reset();
-
-				mLoaded = FALSE;
-				mGetStatus = 0;
-				mGetReason.clear();
-				LL_DEBUGS("Texture") << "HTTP GET: " << mID << " Offset: " << offset
-									 << " Bytes: " << mRequestedSize
-									 << " Bandwidth(kbps): " << mFetcher->getTextureBandwidth() << "/" << mFetcher->mMaxBandwidth
-									 << LL_ENDL;
-				setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
-				mState = WAIT_HTTP_REQ;	
-
-				mFetcher->addToHTTPQueue(mID);
-				if (! mMetricsStartTime)
+				else
 				{
-					mMetricsStartTime = LLViewerAssetStatsFF::get_timestamp();
+					releaseHttpSemaphore();
+					return true; // abort.
 				}
-				LLViewerAssetStatsFF::record_enqueue_thread1(LLViewerAssetType::AT_TEXTURE,
-															 true,
-															 LLImageBase::TYPE_AVATAR_BAKE == mType);
-
-				// Will call callbackHttpGet when curl request completes
-				std::vector<std::string> headers;
-				headers.push_back("Accept: image/x-j2c");
-				res = mFetcher->mCurlGetRequest->getByteRange(mUrl, headers, offset, mRequestedSize,
-															  new HTTPGetResponder(mFetcher, mID, LLTimer::getTotalTime(), mRequestedSize, offset, true));
-			}
-			if (!res)
-			{
-				llwarns << "HTTP GET request failed for " << mID << llendl;
-				resetFormattedData();
-				++mHTTPFailCount;
-				return true; // failed
 			}
-			// fall through
 		}
-		else //can not use http fetch.
+		mRequestedSize = mDesiredSize;
+		mRequestedDiscard = mDesiredDiscard;
+		mRequestedSize -= cur_size;
+		mRequestedOffset = cur_size;
+		mHttpHandle = LLCORE_HTTP_HANDLE_INVALID;
+		if (!mUrl.empty())
 		{
-			return true ; //abort
+			mRequestedTimer.reset();
+			mLoaded = FALSE;
+			mGetStatus = LLCore::HttpStatus();
+			mGetReason.clear();
+			LL_DEBUGS("Texture") << "HTTP GET: " << mID << " Offset: " << mRequestedOffset
+								 << " Bytes: " << mRequestedSize
+								 << " Bandwidth(kbps): " << mFetcher->getTextureBandwidth() << "/" << mFetcher->mMaxBandwidth
+								 << LL_ENDL;
+			
+			// Will call callbackHttpGet when curl request completes
+			mHttpHandle = mFetcher->mHttpRequest->requestGetByteRange(mHttpPolicyClass,
+																	  mWorkPriority,
+																	  mUrl,
+																	  mRequestedOffset,
+																	  mRequestedSize,
+																	  mFetcher->mHttpOptions,
+																	  mFetcher->mHttpHeaders,
+																	  this);
+		}
+		if (LLCORE_HTTP_HANDLE_INVALID == mHttpHandle)
+		{
+			llwarns << "HTTP GET request failed for " << mID << llendl;
+			resetFormattedData();
+			releaseHttpSemaphore();
+			return true; // failed
 		}
+
+		mHttpActive = true;
+		mFetcher->addToHTTPQueue(mID);
+		recordTextureStart(true);
+		setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
+		mState = WAIT_HTTP_REQ;	
+		
+		// fall through
 	}
 	
 	if (mState == WAIT_HTTP_REQ)
@@ -1246,74 +1448,69 @@ bool LLTextureFetchWorker::doWork(S32 param)
 			S32 cur_size = mFormattedImage.notNull() ? mFormattedImage->getDataSize() : 0;
 			if (mRequestedSize < 0)
 			{
-				S32 max_attempts;
-				if (mGetStatus == HTTP_NOT_FOUND)
+				if (http_not_found == mGetStatus)
 				{
-					mHTTPFailCount = max_attempts = 1; // Don't retry
 					llwarns << "Texture missing from server (404): " << mUrl << llendl;
 
-					//roll back to try UDP
-					if(mCanUseNET)
+					// roll back to try UDP
+					if (mCanUseNET)
 					{
-						mState = INIT ;
-						mCanUseHTTP = false ;
+						mState = INIT;
+						mCanUseHTTP = false;
 						setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
-						return false ;
+						releaseHttpSemaphore();
+						return false;
 					}
 				}
-				else if (mGetStatus == HTTP_SERVICE_UNAVAILABLE)
+				else if (http_service_unavail == mGetStatus)
 				{
-					// *TODO: Should probably introduce a timer here to delay future HTTP requsts
-					// for a short time (~1s) to ease server load? Ideally the server would queue
-					// requests instead of returning 503... we already limit the number pending.
-					++mHTTPFailCount;
-					max_attempts = mHTTPFailCount+1; // Keep retrying
 					LL_INFOS_ONCE("Texture") << "Texture server busy (503): " << mUrl << LL_ENDL;
 				}
 				else
 				{
-					const S32 HTTP_MAX_RETRY_COUNT = 3;
-					max_attempts = HTTP_MAX_RETRY_COUNT + 1;
-					++mHTTPFailCount;
 					llinfos << "HTTP GET failed for: " << mUrl
-							<< " Status: " << mGetStatus << " Reason: '" << mGetReason << "'"
-							<< " Attempt:" << mHTTPFailCount+1 << "/" << max_attempts << llendl;
+							<< " Status: " << mGetStatus.toHex()
+							<< " Reason: '" << mGetReason << "'"
+						// *FIXME:  Add retry info for reporting purposes...
+						// << " Attempt:" << mHTTPFailCount+1 << "/" << max_attempts
+							<< llendl;
 				}
 
-				if (mHTTPFailCount >= max_attempts)
+				if (cur_size > 0)
 				{
-					if (cur_size > 0)
-					{
-						// Use available data
-						mLoadedDiscard = mFormattedImage->getDiscardLevel();
-						mState = DECODE_IMAGE;
-						return false; 
-					}
-					else
-					{
-						resetFormattedData();
-						mState = DONE;
-						return true; // failed
-					}
-				}
-				else
-				{
-					mState = SEND_HTTP_REQ;
-					return false; // retry
+					// Use available data
+					mLoadedDiscard = mFormattedImage->getDiscardLevel();
+					mState = DECODE_IMAGE;
+					releaseHttpSemaphore();
+					return false; 
 				}
+
+				// Fail harder
+				resetFormattedData();
+				mState = DONE;
+				releaseHttpSemaphore();
+				return true; // failed
 			}
 			
-			llassert_always(mBufferSize == cur_size + mRequestedSize);
-			if(!mBufferSize)//no data received.
+			if (! mHttpBufferArray || ! mHttpBufferArray->size())
 			{
-				FREE_MEM(LLImageBase::getPrivatePool(), mBuffer); 
-				mBuffer = NULL;
+				// no data received.
+				if (mHttpBufferArray)
+				{
+					mHttpBufferArray->release();
+					mHttpBufferArray = NULL;
+				}
 
-				//abort.
+				// abort.
 				mState = DONE;
+				releaseHttpSemaphore();
 				return true;
 			}
 
+			const S32 append_size(mHttpBufferArray->size());
+			const S32 total_size(cur_size + append_size);
+			llassert_always(append_size == mRequestedSize);
+			
 			if (mFormattedImage.isNull())
 			{
 				// For now, create formatted image based on extension
@@ -1325,34 +1522,37 @@ bool LLTextureFetchWorker::doWork(S32 param)
 				}
 			}
 						
-			if (mHaveAllData && mRequestedDiscard == 0) //the image file is fully loaded.
+			if (mHaveAllData /* && mRequestedDiscard == 0*/) //the image file is fully loaded.
 			{
-				mFileSize = mBufferSize;
+				mFileSize = total_size;
 			}
 			else //the file size is unknown.
 			{
-				mFileSize = mBufferSize + 1 ; //flag the file is not fully loaded.
+				mFileSize = total_size + 1 ; //flag the file is not fully loaded.
 			}
 			
-			U8* buffer = (U8*)ALLOCATE_MEM(LLImageBase::getPrivatePool(), mBufferSize);
+			U8 * buffer = (U8 *) ALLOCATE_MEM(LLImageBase::getPrivatePool(), total_size);
 			if (cur_size > 0)
 			{
 				memcpy(buffer, mFormattedImage->getData(), cur_size);
 			}
-			memcpy(buffer + cur_size, mBuffer, mRequestedSize); // append
+			mHttpBufferArray->read(0, (char *) buffer + cur_size, append_size);
+
 			// NOTE: setData releases current data and owns new data (buffer)
-			mFormattedImage->setData(buffer, mBufferSize);
-			// delete temp data
-			FREE_MEM(LLImageBase::getPrivatePool(), mBuffer); // Note: not 'buffer' (assigned in setData())
-			mBuffer = NULL;
-			mBufferSize = 0;
+			mFormattedImage->setData(buffer, total_size);
+
+			// Done with buffer array
+			mHttpBufferArray->release();
+			mHttpBufferArray = NULL;
+			
 			mLoadedDiscard = mRequestedDiscard;
 			mState = DECODE_IMAGE;
-			if(mWriteToCacheState != NOT_WRITE)
+			if (mWriteToCacheState != NOT_WRITE)
 			{
 				mWriteToCacheState = SHOULD_WRITE ;
 			}
 			setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
+			releaseHttpSemaphore();
 			return false;
 		}
 		else
@@ -1372,11 +1572,12 @@ bool LLTextureFetchWorker::doWork(S32 param)
 	if (mState == DECODE_IMAGE)
 	{
 		static LLCachedControl<bool> textures_decode_disabled(gSavedSettings,"TextureDecodeDisabled");
-		if(textures_decode_disabled)
+
+		setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority); // Set priority first since Responder may change it
+		if (textures_decode_disabled)
 		{
 			// for debug use, don't decode
 			mState = DONE;
-			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
 			return true;
 		}
 
@@ -1384,7 +1585,6 @@ bool LLTextureFetchWorker::doWork(S32 param)
 		{
 			// We aborted, don't decode
 			mState = DONE;
-			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
 			return true;
 		}
 		
@@ -1394,7 +1594,6 @@ bool LLTextureFetchWorker::doWork(S32 param)
 			
 			//abort, don't decode
 			mState = DONE;
-			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
 			return true;
 		}
 		if (mLoadedDiscard < 0)
@@ -1403,15 +1602,14 @@ bool LLTextureFetchWorker::doWork(S32 param)
 
 			//abort, don't decode
 			mState = DONE;
-			setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
 			return true;
 		}
-		setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority); // Set priority first since Responder may change it
+
 		mRawImage = NULL;
 		mAuxImage = NULL;
 		llassert_always(mFormattedImage.notNull());
 		S32 discard = mHaveAllData ? 0 : mLoadedDiscard;
-		U32 image_priority = LLWorkerThread::PRIORITY_NORMAL | mWorkPriority;
+		U32 image_priority = LLWorkerThread::PRIORITY_LOW | mWorkPriority;
 		mDecoded  = FALSE;
 		mState = DECODE_IMAGE_UPDATE;
 		LL_DEBUGS("Texture") << mID << ": Decoding. Bytes: " << mFormattedImage->getDataSize() << " Discard: " << discard
@@ -1492,6 +1690,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 		U32 cache_priority = mWorkPriority;
 		mWritten = FALSE;
 		mState = WAIT_ON_WRITE;
+		++mCacheWriteCount;
 		CacheWriteResponder* responder = new CacheWriteResponder(mFetcher, mID);
 		mCacheWriteHandle = mFetcher->mTextureCache->writeToCache(mID, cache_priority,
 																  mFormattedImage->getData(), datasize,
@@ -1521,7 +1720,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
 
 	if (mState == DONE)
 	{
-		if (mDecodedDiscard >= 0 && mDesiredDiscard < mDecodedDiscard)
+		if (mDecodedDiscard > 0 && mDesiredDiscard < mDecodedDiscard)
 		{
 			// More data was requested, return to INIT
 			mState = INIT;
@@ -1536,9 +1735,84 @@ bool LLTextureFetchWorker::doWork(S32 param)
 	}
 	
 	return false;
-}
+}																		// -Mw
+
+// Threads:  Ttf
+// virtual
+void LLTextureFetchWorker::onCompleted(LLCore::HttpHandle handle, LLCore::HttpResponse * response)
+{
+	static LLCachedControl<bool> log_to_viewer_log(gSavedSettings, "LogTextureDownloadsToViewerLog");
+	static LLCachedControl<bool> log_to_sim(gSavedSettings, "LogTextureDownloadsToSimulator");
+	static LLCachedControl<bool> log_texture_traffic(gSavedSettings, "LogTextureNetworkTraffic") ;
+
+	LLMutexLock lock(&mWorkMutex);										// +Mw
+
+	mHttpActive = false;
+	
+	if (log_to_viewer_log || log_to_sim)
+	{
+		U64 timeNow = LLTimer::getTotalTime();
+		mFetcher->mTextureInfo.setRequestStartTime(mID, mMetricsStartTime);
+		mFetcher->mTextureInfo.setRequestType(mID, LLTextureInfoDetails::REQUEST_TYPE_HTTP);
+		mFetcher->mTextureInfo.setRequestSize(mID, mRequestedSize);
+		mFetcher->mTextureInfo.setRequestOffset(mID, mRequestedOffset);
+		mFetcher->mTextureInfo.setRequestCompleteTimeAndLog(mID, timeNow);
+	}
+
+	bool success = true;
+	bool partial = false;
+	LLCore::HttpStatus status(response->getStatus());
+	
+	lldebugs << "HTTP COMPLETE: " << mID
+			 << " status: " << status.toHex()
+			 << " '" << status.toString() << "'"
+			 << llendl;
+//	unsigned int offset(0), length(0), full_length(0);
+//	response->getRange(&offset, &length, &full_length);
+// 	llwarns << "HTTP COMPLETE: " << mID << " handle: " << handle
+// 			<< " status: " << status.toULong() << " '" << status.toString() << "'"
+// 			<< " req offset: " << mRequestedOffset << " req length: " << mRequestedSize
+// 			<< " offset: " << offset << " length: " << length
+// 			<< llendl;
+
+	if (! status)
+	{
+		success = false;
+		std::string reason(status.toString());
+		setGetStatus(status, reason);
+ 		llwarns << "CURL GET FAILED, status: " << status.toHex()
+				<< " reason: " << reason << llendl;
+	}
+	else
+	{
+		// A warning about partial (HTTP 206) data.  Some grid services
+		// do *not* return a 'Content-Range' header in the response to
+		// Range requests with a 206 status.  We're forced to assume
+		// we get what we asked for in these cases until we can fix
+		// the services.
+		static const LLCore::HttpStatus par_status(HTTP_PARTIAL_CONTENT);
 
-// Called from MAIN thread
+		partial = (par_status == status);
+	}
+	
+	S32 data_size = callbackHttpGet(response, partial, success);
+			
+	if (log_texture_traffic && data_size > 0)
+	{
+		LLViewerTexture* tex = LLViewerTextureManager::findTexture(mID);
+		if (tex)
+		{
+			gTotalTextureBytesPerBoostLevel[tex->getBoostLevel()] += data_size ;
+		}
+	}
+
+	mFetcher->removeFromHTTPQueue(mID);
+	
+	recordTextureDone(true);
+}																		// -Mw
+
+
+// Threads:  Tmain
 void LLTextureFetchWorker::endWork(S32 param, bool aborted)
 {
 	if (mDecodeHandle != 0)
@@ -1551,6 +1825,8 @@ void LLTextureFetchWorker::endWork(S32 param, bool aborted)
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  Ttf
+
 // virtual
 void LLTextureFetchWorker::finishWork(S32 param, bool completed)
 {
@@ -1567,10 +1843,25 @@ void LLTextureFetchWorker::finishWork(S32 param, bool completed)
 	}
 }
 
+// LLQueuedThread's update() method is asking if it's okay to
+// delete this worker.  You'll notice we're not locking in here
+// which is a slight concern.  Caller is expected to have made
+// this request 'quiet' by whatever means... 
+//
+// Threads:  Tmain
+
 // virtual
 bool LLTextureFetchWorker::deleteOK()
 {
 	bool delete_ok = true;
+
+	if (mHttpActive)
+	{
+		// HTTP library has a pointer to this worker
+		// and will dereference it to do notification.
+		delete_ok = false;
+	}
+	
 	// Allow any pending reads or writes to complete
 	if (mCacheReadHandle != LLTextureCache::nullHandle())
 	{
@@ -1605,6 +1896,7 @@ bool LLTextureFetchWorker::deleteOK()
 	return delete_ok;
 }
 
+// Threads:  Ttf
 void LLTextureFetchWorker::removeFromCache()
 {
 	if (!mInLocalCache)
@@ -1616,6 +1908,8 @@ void LLTextureFetchWorker::removeFromCache()
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  Ttf
+// Locks:  Mw
 bool LLTextureFetchWorker::processSimulatorPackets()
 {
 	if (mFormattedImage.isNull() || mRequestedSize < 0)
@@ -1676,14 +1970,13 @@ bool LLTextureFetchWorker::processSimulatorPackets()
 
 //////////////////////////////////////////////////////////////////////////////
 
-S32 LLTextureFetchWorker::callbackHttpGet(const LLChannelDescriptors& channels,
-										   const LLIOPipe::buffer_ptr_t& buffer,
-										   bool partial, bool success)
+// Threads:  Ttf
+// Locks:  Mw
+S32 LLTextureFetchWorker::callbackHttpGet(LLCore::HttpResponse * response,
+										  bool partial, bool success)
 {
 	S32 data_size = 0 ;
 
-	LLMutexLock lock(&mWorkMutex);
-
 	if (mState != WAIT_HTTP_REQ)
 	{
 		llwarns << "callbackHttpGet for unrequested fetch worker: " << mID
@@ -1698,27 +1991,52 @@ S32 LLTextureFetchWorker::callbackHttpGet(const LLChannelDescriptors& channels,
 	if (success)
 	{
 		// get length of stream:
-		data_size = buffer->countAfter(channels.in(), NULL);		
-	
+		LLCore::BufferArray * body(response->getBody());
+		data_size = body ? body->size() : 0;
+
 		LL_DEBUGS("Texture") << "HTTP RECEIVED: " << mID.asString() << " Bytes: " << data_size << LL_ENDL;
 		if (data_size > 0)
 		{
 			// *TODO: set the formatted image data here directly to avoid the copy
-			mBuffer = (U8*)ALLOCATE_MEM(LLImageBase::getPrivatePool(), data_size);
-			buffer->readAfter(channels.in(), NULL, mBuffer, data_size);
-			mBufferSize += data_size;
-			if (data_size < mRequestedSize && mRequestedDiscard == 0)
+			// *FIXME:  deal with actual offset and actual datasize, don't assume
+			// server gave exactly what was asked for.
+			
+			llassert_always(NULL == mHttpBufferArray);
+
+			// Hold on to body for later copy
+			body->addRef();
+			mHttpBufferArray = body;
+
+			if (! partial)
+			{
+				// Response indicates this is the entire asset regardless
+				// of our asking for a byte range.  Mark it so and drop
+				// any partial data we might have so that the current
+				// response body becomes the entire dataset.
+				if (data_size <= mRequestedOffset)
+				{
+					LL_WARNS("Texture") << "Fetched entire texture " << mID
+										<< " when it was expected to be marked complete.  mImageSize:  "
+										<< mFileSize << " datasize:  " << mFormattedImage->getDataSize()
+										<< LL_ENDL;
+				}
+				mHaveAllData = TRUE;
+				llassert_always(mDecodeHandle == 0);
+				mFormattedImage = NULL; // discard any previous data we had
+			}
+			else if (data_size < mRequestedSize /*&& mRequestedDiscard == 0*/)
 			{
+				// *FIXME:  I think we can treat this as complete regardless
+				// of requested discard level.  Revisit this...
 				mHaveAllData = TRUE;
 			}
 			else if (data_size > mRequestedSize)
 			{
-				// *TODO: This shouldn't be happening any more
+				// *TODO: This shouldn't be happening any more  (REALLY don't expect this anymore)
 				llwarns << "data_size = " << data_size << " > requested: " << mRequestedSize << llendl;
 				mHaveAllData = TRUE;
 				llassert_always(mDecodeHandle == 0);
 				mFormattedImage = NULL; // discard any previous data we had
-				mBufferSize = data_size;
 			}
 		}
 		else
@@ -1741,10 +2059,11 @@ S32 LLTextureFetchWorker::callbackHttpGet(const LLChannelDescriptors& channels,
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  Ttc
 void LLTextureFetchWorker::callbackCacheRead(bool success, LLImageFormatted* image,
 											 S32 imagesize, BOOL islocal)
 {
-	LLMutexLock lock(&mWorkMutex);
+	LLMutexLock lock(&mWorkMutex);										// +Mw
 	if (mState != LOAD_FROM_TEXTURE_CACHE)
 	{
 // 		llwarns << "Read callback for " << mID << " with state = " << mState << llendl;
@@ -1764,11 +2083,12 @@ void LLTextureFetchWorker::callbackCacheRead(bool success, LLImageFormatted* ima
 	}
 	mLoaded = TRUE;
 	setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
-}
+}																		// -Mw
 
+// Threads:  Ttc
 void LLTextureFetchWorker::callbackCacheWrite(bool success)
 {
-	LLMutexLock lock(&mWorkMutex);
+	LLMutexLock lock(&mWorkMutex);										// +Mw
 	if (mState != WAIT_ON_WRITE)
 	{
 // 		llwarns << "Write callback for " << mID << " with state = " << mState << llendl;
@@ -1776,13 +2096,14 @@ void LLTextureFetchWorker::callbackCacheWrite(bool success)
 	}
 	mWritten = TRUE;
 	setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
-}
+}																		// -Mw
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  Tid
 void LLTextureFetchWorker::callbackDecoded(bool success, LLImageRaw* raw, LLImageRaw* aux)
 {
-	LLMutexLock lock(&mWorkMutex);
+	LLMutexLock lock(&mWorkMutex);										// +Mw
 	if (mDecodeHandle == 0)
 	{
 		return; // aborted, ignore
@@ -1815,10 +2136,11 @@ void LLTextureFetchWorker::callbackDecoded(bool success, LLImageRaw* raw, LLImag
 // 	llinfos << mID << " : DECODE COMPLETE " << llendl;
 	setPriority(LLWorkerThread::PRIORITY_HIGH | mWorkPriority);
 	mCacheReadTime = mCacheReadTimer.getElapsedTimeF32();
-}
+}																		// -Mw
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  Ttf
 bool LLTextureFetchWorker::writeToCacheComplete()
 {
 	// Complete write to cache
@@ -1841,6 +2163,36 @@ bool LLTextureFetchWorker::writeToCacheComplete()
 }
 
 
+// Threads:  Ttf
+void LLTextureFetchWorker::recordTextureStart(bool is_http)
+{
+	if (! mMetricsStartTime)
+	{
+		mMetricsStartTime = LLViewerAssetStatsFF::get_timestamp();
+	}
+	LLViewerAssetStatsFF::record_enqueue_thread1(LLViewerAssetType::AT_TEXTURE,
+												 is_http,
+												 LLImageBase::TYPE_AVATAR_BAKE == mType);
+}
+
+
+// Threads:  Ttf
+void LLTextureFetchWorker::recordTextureDone(bool is_http)
+{
+	if (mMetricsStartTime)
+	{
+		LLViewerAssetStatsFF::record_response_thread1(LLViewerAssetType::AT_TEXTURE,
+													  is_http,
+													  LLImageBase::TYPE_AVATAR_BAKE == mType,
+													  LLViewerAssetStatsFF::get_timestamp() - mMetricsStartTime);
+		mMetricsStartTime = 0;
+	}
+	LLViewerAssetStatsFF::record_dequeue_thread1(LLViewerAssetType::AT_TEXTURE,
+												 is_http,
+												 LLImageBase::TYPE_AVATAR_BAKE == mType);
+}
+
+
 //////////////////////////////////////////////////////////////////////////////
 //////////////////////////////////////////////////////////////////////////////
 // public
@@ -1858,12 +2210,18 @@ LLTextureFetch::LLTextureFetch(LLTextureCache* cache, LLImageDecodeThread* image
 	  mTextureBandwidth(0),
 	  mHTTPTextureBits(0),
 	  mTotalHTTPRequests(0),
-	  mCurlGetRequest(NULL),
 	  mQAMode(qa_mode),
+	  mHttpRequest(NULL),
+	  mHttpOptions(NULL),
+	  mHttpHeaders(NULL),
+	  mHttpMetricsHeaders(NULL),
+	  mHttpSemaphore(HTTP_REQUESTS_IN_QUEUE_HIGH_WATER),
+	  mTotalCacheReadCount(0U),
+	  mTotalCacheWriteCount(0U),
+	  mTotalResourceWaitCount(0U),
 	  mFetchDebugger(NULL),
 	  mFetcherLocked(FALSE)
 {
-	mCurlPOSTRequestCount = 0;
 	mMaxBandwidth = gSavedSettings.getF32("ThrottleBandwidthKBPS");
 	mTextureInfo.setUpLogging(gSavedSettings.getBOOL("LogTextureDownloadsToViewerLog"), gSavedSettings.getBOOL("LogTextureDownloadsToSimulator"), gSavedSettings.getU32("TextureLoggingThreshold"));
 
@@ -1872,11 +2230,18 @@ LLTextureFetch::LLTextureFetch(LLTextureCache* cache, LLImageDecodeThread* image
 	{
 		mFetchDebugger = new LLTextureFetchDebugger(this, cache, imagedecodethread) ;
 	}
+	
+	mHttpRequest = new LLCore::HttpRequest;
+	mHttpOptions = new LLCore::HttpOptions;
+	mHttpHeaders = new LLCore::HttpHeaders;
+	mHttpHeaders->mHeaders.push_back("Accept: image/x-j2c");
+	mHttpMetricsHeaders = new LLCore::HttpHeaders;
+	mHttpMetricsHeaders->mHeaders.push_back("Content-Type: application/llsd+xml");
 }
 
 LLTextureFetch::~LLTextureFetch()
 {
-	clearDeleteList() ;
+	clearDeleteList();
 
 	while (! mCommands.empty())
 	{
@@ -1884,10 +2249,34 @@ LLTextureFetch::~LLTextureFetch()
 		mCommands.erase(mCommands.begin());
 		delete req;
 	}
+
+	if (mHttpOptions)
+	{
+		mHttpOptions->release();
+		mHttpOptions = NULL;
+	}
+
+	if (mHttpHeaders)
+	{
+		mHttpHeaders->release();
+		mHttpHeaders = NULL;
+	}
+
+	if (mHttpMetricsHeaders)
+	{
+		mHttpMetricsHeaders->release();
+		mHttpMetricsHeaders = NULL;
+	}
+
+	mHttpWaitResource.clear();
 	
-	// ~LLQueuedThread() called here
+	delete mHttpRequest;
+	mHttpRequest = NULL;
 
 	delete mFetchDebugger;
+	mFetchDebugger = NULL;
+	
+	// ~LLQueuedThread() called here
 }
 
 bool LLTextureFetch::createRequest(const std::string& url, const LLUUID& id, const LLHost& host, F32 priority,
@@ -1951,7 +2340,7 @@ bool LLTextureFetch::createRequest(const std::string& url, const LLUUID& id, con
 		{
 			return false; // need to wait for previous aborted request to complete
 		}
-		worker->lockWorkMutex();
+		worker->lockWorkMutex();										// +Mw
 		worker->mActiveCount++;
 		worker->mNeedsAux = needs_aux;
 		worker->setImagePriority(priority);
@@ -1960,41 +2349,44 @@ bool LLTextureFetch::createRequest(const std::string& url, const LLUUID& id, con
 		if (!worker->haveWork())
 		{
 			worker->mState = LLTextureFetchWorker::INIT;
-			worker->unlockWorkMutex();
+			worker->unlockWorkMutex();									// -Mw
 
 			worker->addWork(0, LLWorkerThread::PRIORITY_HIGH | worker->mWorkPriority);
 		}
 		else
 		{
-			worker->unlockWorkMutex();
+			worker->unlockWorkMutex();									// -Mw
 		}
 	}
 	else
 	{
 		worker = new LLTextureFetchWorker(this, url, id, host, priority, desired_discard, desired_size);
-		lockQueue() ;
+		lockQueue();													// +Mfq
 		mRequestMap[id] = worker;
-		unlockQueue() ;
+		unlockQueue();													// -Mfq
 
-		worker->lockWorkMutex();
+		worker->lockWorkMutex();										// +Mw
 		worker->mActiveCount++;
 		worker->mNeedsAux = needs_aux;
 		worker->setCanUseHTTP(can_use_http) ;
-		worker->unlockWorkMutex();
+		worker->unlockWorkMutex();										// -Mw
 	}
 	
 // 	llinfos << "REQUESTED: " << id << " Discard: " << desired_discard << llendl;
 	return true;
 }
 
+
+// Threads:  T* (but Ttf in practice)
+
 // protected
 void LLTextureFetch::addToNetworkQueue(LLTextureFetchWorker* worker)
 {
-	lockQueue() ;
+	lockQueue();														// +Mfq
 	bool in_request_map = (mRequestMap.find(worker->mID) != mRequestMap.end()) ;
-	unlockQueue() ;
+	unlockQueue();														// -Mfq
 
-	LLMutexLock lock(&mNetworkQueueMutex);
+	LLMutexLock lock(&mNetworkQueueMutex);								// +Mfnq		
 	if (in_request_map)
 	{
 		// only add to the queue if in the request map
@@ -2006,41 +2398,50 @@ void LLTextureFetch::addToNetworkQueue(LLTextureFetchWorker* worker)
 	{
 		iter1->second.erase(worker->mID);
 	}
-}
+}																		// -Mfnq
 
+// Threads:  T*
 void LLTextureFetch::removeFromNetworkQueue(LLTextureFetchWorker* worker, bool cancel)
 {
-	LLMutexLock lock(&mNetworkQueueMutex);
+	LLMutexLock lock(&mNetworkQueueMutex);								// +Mfnq
 	size_t erased = mNetworkQueue.erase(worker->mID);
 	if (cancel && erased > 0)
 	{
 		mCancelQueue[worker->mHost].insert(worker->mID);
 	}
-}
+}																		// -Mfnq
 
+// Threads:  T*
+//
 // protected
 void LLTextureFetch::addToHTTPQueue(const LLUUID& id)
 {
-	LLMutexLock lock(&mNetworkQueueMutex);
+	LLMutexLock lock(&mNetworkQueueMutex);								// +Mfnq
 	mHTTPTextureQueue.insert(id);
 	mTotalHTTPRequests++;
-}
+}																		// -Mfnq
 
+// Threads:  T*
 void LLTextureFetch::removeFromHTTPQueue(const LLUUID& id, S32 received_size)
 {
-	LLMutexLock lock(&mNetworkQueueMutex);
+	LLMutexLock lock(&mNetworkQueueMutex);								// +Mfnq
 	mHTTPTextureQueue.erase(id);
 	mHTTPTextureBits += received_size * 8; // Approximate - does not include header bits	
-}
+}																		// -Mfnq
 
+// NB:  If you change deleteRequest() you should probably make
+// parallel changes in removeRequest().  They're functionally
+// identical with only argument variations.
+//
+// Threads:  T*
 void LLTextureFetch::deleteRequest(const LLUUID& id, bool cancel)
 {
-	lockQueue() ;
+	lockQueue();														// +Mfq
 	LLTextureFetchWorker* worker = getWorkerAfterLock(id);
 	if (worker)
 	{		
 		size_t erased_1 = mRequestMap.erase(worker->mID);
-		unlockQueue() ;
+		unlockQueue();													// -Mfq
 
 		llassert_always(erased_1 > 0) ;
 
@@ -2051,15 +2452,20 @@ void LLTextureFetch::deleteRequest(const LLUUID& id, bool cancel)
 	}
 	else
 	{
-		unlockQueue() ;
+		unlockQueue();													// -Mfq
 	}
 }
 
+// NB:  If you change removeRequest() you should probably make
+// parallel changes in deleteRequest().  They're functionally
+// identical with only argument variations.
+//
+// Threads:  T*
 void LLTextureFetch::removeRequest(LLTextureFetchWorker* worker, bool cancel)
 {
-	lockQueue() ;
+	lockQueue();														// +Mfq
 	size_t erased_1 = mRequestMap.erase(worker->mID);
-	unlockQueue() ;
+	unlockQueue();														// -Mfq
 
 	llassert_always(erased_1 > 0) ;
 	removeFromNetworkQueue(worker, cancel);
@@ -2068,34 +2474,39 @@ void LLTextureFetch::removeRequest(LLTextureFetchWorker* worker, bool cancel)
 	worker->scheduleDelete();	
 }
 
+// Threads:  T*
 S32 LLTextureFetch::getNumRequests() 
 { 
-	lockQueue() ;
+	lockQueue();														// +Mfq
 	S32 size = (S32)mRequestMap.size(); 
-	unlockQueue() ;
+	unlockQueue();														// -Mfq
 
-	return size ;
+	return size;
 }
 
+// Threads:  T*
 S32 LLTextureFetch::getNumHTTPRequests() 
 { 
-	mNetworkQueueMutex.lock() ;
+	mNetworkQueueMutex.lock();											// +Mfq
 	S32 size = (S32)mHTTPTextureQueue.size(); 
-	mNetworkQueueMutex.unlock() ;
+	mNetworkQueueMutex.unlock();										// -Mfq
 
-	return size ;
+	return size;
 }
 
+// Threads:  T*
 U32 LLTextureFetch::getTotalNumHTTPRequests()
 {
-	mNetworkQueueMutex.lock() ;
-	U32 size = mTotalHTTPRequests ;
-	mNetworkQueueMutex.unlock() ;
+	mNetworkQueueMutex.lock();											// +Mfq
+	U32 size = mTotalHTTPRequests;
+	mNetworkQueueMutex.unlock();										// -Mfq
 
-	return size ;
+	return size;
 }
 
 // call lockQueue() first!
+// Threads:  T*
+// Locks:  Mfq
 LLTextureFetchWorker* LLTextureFetch::getWorkerAfterLock(const LLUUID& id)
 {
 	LLTextureFetchWorker* res = NULL;
@@ -2107,14 +2518,16 @@ LLTextureFetchWorker* LLTextureFetch::getWorkerAfterLock(const LLUUID& id)
 	return res;
 }
 
+// Threads:  T*
 LLTextureFetchWorker* LLTextureFetch::getWorker(const LLUUID& id)
 {
-	LLMutexLock lock(&mQueueMutex) ;
+	LLMutexLock lock(&mQueueMutex);										// +Mfq
 
-	return getWorkerAfterLock(id) ;
-}
+	return getWorkerAfterLock(id);
+}																		// -Mfq
 
 
+// Threads:  T*
 bool LLTextureFetch::getRequestFinished(const LLUUID& id, S32& discard_level,
 										LLPointer<LLImageRaw>& raw, LLPointer<LLImageRaw>& aux)
 {
@@ -2137,7 +2550,7 @@ bool LLTextureFetch::getRequestFinished(const LLUUID& id, S32& discard_level,
 		}
 		else if (worker->checkWork())
 		{
-			worker->lockWorkMutex();
+			worker->lockWorkMutex();									// +Mw
 			discard_level = worker->mDecodedDiscard;
 			raw = worker->mRawImage;
 			aux = worker->mAuxImage;
@@ -2148,11 +2561,11 @@ bool LLTextureFetch::getRequestFinished(const LLUUID& id, S32& discard_level,
 			}
 			res = true;
 			LL_DEBUGS("Texture") << id << ": Request Finished. State: " << worker->mState << " Discard: " << discard_level << LL_ENDL;
-			worker->unlockWorkMutex();
+			worker->unlockWorkMutex();									// -Mw
 		}
 		else
 		{
-			worker->lockWorkMutex();
+			worker->lockWorkMutex();									// +Mw
 			if ((worker->mDecodedDiscard >= 0) &&
 				(worker->mDecodedDiscard < discard_level || discard_level < 0) &&
 				(worker->mState >= LLTextureFetchWorker::WAIT_ON_WRITE))
@@ -2162,7 +2575,7 @@ bool LLTextureFetch::getRequestFinished(const LLUUID& id, S32& discard_level,
 				raw = worker->mRawImage;
 				aux = worker->mAuxImage;
 			}
-			worker->unlockWorkMutex();
+			worker->unlockWorkMutex();									// -Mw
 		}
 	}
 	else
@@ -2172,15 +2585,16 @@ bool LLTextureFetch::getRequestFinished(const LLUUID& id, S32& discard_level,
 	return res;
 }
 
+// Threads:  T*
 bool LLTextureFetch::updateRequestPriority(const LLUUID& id, F32 priority)
 {
 	bool res = false;
 	LLTextureFetchWorker* worker = getWorker(id);
 	if (worker)
 	{
-		worker->lockWorkMutex();
+		worker->lockWorkMutex();										// +Mw
 		worker->setImagePriority(priority);
-		worker->unlockWorkMutex();
+		worker->unlockWorkMutex();										// -Mw
 		res = true;
 	}
 	return res;
@@ -2195,24 +2609,24 @@ bool LLTextureFetch::updateRequestPriority(const LLUUID& id, F32 priority)
 // in step, at least until this can be refactored and
 // the redundancy eliminated.
 //
-// May be called from any thread
+// Threads:  T*
 
 //virtual
 S32 LLTextureFetch::getPending()
 {
 	S32 res;
-	lockData();
+	lockData();															// +Ct
     {
-        LLMutexLock lock(&mQueueMutex);
+        LLMutexLock lock(&mQueueMutex);									// +Mfq
         
         res = mRequestQueue.size();
-        res += mCurlPOSTRequestCount;
         res += mCommands.size();
-    }
-	unlockData();
+    }																	// -Mfq
+	unlockData();														// -Ct
 	return res;
 }
 
+// Locks:  Ct
 // virtual
 bool LLTextureFetch::runCondition()
 {
@@ -2227,49 +2641,57 @@ bool LLTextureFetch::runCondition()
 	
 	bool have_no_commands(false);
 	{
-		LLMutexLock lock(&mQueueMutex);
+		LLMutexLock lock(&mQueueMutex);									// +Mfq
 		
 		have_no_commands = mCommands.empty();
-	}
-	
-    bool have_no_curl_requests(0 == mCurlPOSTRequestCount);
+	}																	// -Mfq
 	
 	return ! (have_no_commands
-			  && have_no_curl_requests
 			  && (mRequestQueue.empty() && mIdleThread));		// From base class
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
-// MAIN THREAD (unthreaded envs), WORKER THREAD (threaded envs)
+// Threads:  Ttf
 void LLTextureFetch::commonUpdate()
 {
 	// Run a cross-thread command, if any.
 	cmdDoWork();
 	
 	// Update Curl on same thread as mCurlGetRequest was constructed
-	S32 processed = mCurlGetRequest->process();
+	LLCore::HttpStatus status = mHttpRequest->update(200);
+	if (! status)
+	{
+		LL_INFOS_ONCE("Texture") << "Problem during HTTP servicing.  Reason:  "
+								 << status.toString()
+								 << LL_ENDL;
+	}
+		
+#if 0
+	// *FIXME:  maybe implement this another way...
 	if (processed > 0)
 	{
 		lldebugs << "processed: " << processed << " messages." << llendl;
 	}
+#endif
 }
 
 
-// MAIN THREAD
+// Threads:  Tmain
+
 //virtual
 S32 LLTextureFetch::update(F32 max_time_ms)
 {
 	static LLCachedControl<F32> band_width(gSavedSettings,"ThrottleBandwidthKBPS");
 
 	{
-		mNetworkQueueMutex.lock() ;
-		mMaxBandwidth = band_width ;
+		mNetworkQueueMutex.lock();										// +Mfnq
+		mMaxBandwidth = band_width;
 
-		gTextureList.sTextureBits += mHTTPTextureBits ;
-		mHTTPTextureBits = 0 ;
+		gTextureList.sTextureBits += mHTTPTextureBits;
+		mHTTPTextureBits = 0;
 
-		mNetworkQueueMutex.unlock() ;
+		mNetworkQueueMutex.unlock();									// -Mfnq
 	}
 
 	S32 res = LLWorkerThread::update(max_time_ms);
@@ -2293,7 +2715,9 @@ S32 LLTextureFetch::update(F32 max_time_ms)
 	return res;
 }
 
-//called in the MAIN thread after the TextureCacheThread shuts down.
+// called in the MAIN thread after the TextureCacheThread shuts down.
+//
+// Threads:  Tmain
 void LLTextureFetch::shutDownTextureCacheThread() 
 {
 	if(mTextureCache)
@@ -2303,7 +2727,9 @@ void LLTextureFetch::shutDownTextureCacheThread()
 	}
 }
 	
-//called in the MAIN thread after the ImageDecodeThread shuts down.
+// called in the MAIN thread after the ImageDecodeThread shuts down.
+//
+// Threads:  Tmain
 void LLTextureFetch::shutDownImageDecodeThread() 
 {
 	if(mImageDecodeThread)
@@ -2313,34 +2739,25 @@ void LLTextureFetch::shutDownImageDecodeThread()
 	}
 }
 
-// WORKER THREAD
+// Threads:  Ttf
 void LLTextureFetch::startThread()
 {
-	// Construct mCurlGetRequest from Worker Thread
-	mCurlGetRequest = new LLCurlRequest();
-	
-	if(mFetchDebugger)
-	{
-		mFetchDebugger->setCurlGetRequest(mCurlGetRequest);
-	}
 }
 
-// WORKER THREAD
+// Threads:  Ttf
 void LLTextureFetch::endThread()
 {
-	// Destroy mCurlGetRequest from Worker Thread
-	delete mCurlGetRequest;
-	mCurlGetRequest = NULL;
-	if(mFetchDebugger)
-	{
-		mFetchDebugger->setCurlGetRequest(NULL);
-	}
+	LL_INFOS("Texture") << "CacheReads:  " << mTotalCacheReadCount
+						<< ", CacheWrites:  " << mTotalCacheWriteCount
+						<< ", ResWaits:  " << mTotalResourceWaitCount
+						<< ", TotalHTTPReq:  " << getTotalNumHTTPRequests()
+						<< LL_ENDL;
 }
 
-// WORKER THREAD
+// Threads:  Ttf
 void LLTextureFetch::threadedUpdate()
 {
-	llassert_always(mCurlGetRequest);
+	llassert_always(mHttpRequest);
 	
 	// Limit update frequency
 	const F32 PROCESS_TIME = 0.05f; 
@@ -2371,6 +2788,7 @@ void LLTextureFetch::threadedUpdate()
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  Tmain
 void LLTextureFetch::sendRequestListToSimulators()
 {
 	// All requests
@@ -2396,48 +2814,48 @@ void LLTextureFetch::sendRequestListToSimulators()
 	typedef std::map< LLHost, request_list_t > work_request_map_t;
 	work_request_map_t requests;
 	{
-	LLMutexLock lock2(&mNetworkQueueMutex);
-	for (queue_t::iterator iter = mNetworkQueue.begin(); iter != mNetworkQueue.end(); )
-	{
-		queue_t::iterator curiter = iter++;
-		LLTextureFetchWorker* req = getWorker(*curiter);
-		if (!req)
-		{
-			mNetworkQueue.erase(curiter);
-			continue; // paranoia
-		}
-		if ((req->mState != LLTextureFetchWorker::LOAD_FROM_NETWORK) &&
-			(req->mState != LLTextureFetchWorker::LOAD_FROM_SIMULATOR))
-		{
-			// We already received our URL, remove from the queue
-			llwarns << "Worker: " << req->mID << " in mNetworkQueue but in wrong state: " << req->mState << llendl;
-			mNetworkQueue.erase(curiter);
-			continue;
-		}
-		if (req->mID == mDebugID)
-		{
-			mDebugCount++; // for setting breakpoints
-		}
-		if (req->mSentRequest == LLTextureFetchWorker::SENT_SIM &&
-			req->mTotalPackets > 0 &&
-			req->mLastPacket >= req->mTotalPackets-1)
+		LLMutexLock lock2(&mNetworkQueueMutex);							// +Mfnq
+		for (queue_t::iterator iter = mNetworkQueue.begin(); iter != mNetworkQueue.end(); )
 		{
-			// We have all the packets... make sure this is high priority
+			queue_t::iterator curiter = iter++;
+			LLTextureFetchWorker* req = getWorker(*curiter);
+			if (!req)
+			{
+				mNetworkQueue.erase(curiter);
+				continue; // paranoia
+			}
+			if ((req->mState != LLTextureFetchWorker::LOAD_FROM_NETWORK) &&
+				(req->mState != LLTextureFetchWorker::LOAD_FROM_SIMULATOR))
+			{
+				// We already received our URL, remove from the queue
+				llwarns << "Worker: " << req->mID << " in mNetworkQueue but in wrong state: " << req->mState << llendl;
+				mNetworkQueue.erase(curiter);
+				continue;
+			}
+			if (req->mID == mDebugID)
+			{
+				mDebugCount++; // for setting breakpoints
+			}
+			if (req->mSentRequest == LLTextureFetchWorker::SENT_SIM &&
+				req->mTotalPackets > 0 &&
+				req->mLastPacket >= req->mTotalPackets-1)
+			{
+				// We have all the packets... make sure this is high priority
 // 			req->setPriority(LLWorkerThread::PRIORITY_HIGH | req->mWorkPriority);
-			continue;
-		}
-		F32 elapsed = req->mRequestedTimer.getElapsedTimeF32();
-		{
-			F32 delta_priority = llabs(req->mRequestedPriority - req->mImagePriority);
-			if ((req->mSimRequestedDiscard != req->mDesiredDiscard) ||
-				(delta_priority > MIN_DELTA_PRIORITY && elapsed >= MIN_REQUEST_TIME) ||
-				(elapsed >= SIM_LAZY_FLUSH_TIMEOUT))
+				continue;
+			}
+			F32 elapsed = req->mRequestedTimer.getElapsedTimeF32();
 			{
-				requests[req->mHost].insert(req);
+				F32 delta_priority = llabs(req->mRequestedPriority - req->mImagePriority);
+				if ((req->mSimRequestedDiscard != req->mDesiredDiscard) ||
+					(delta_priority > MIN_DELTA_PRIORITY && elapsed >= MIN_REQUEST_TIME) ||
+					(elapsed >= SIM_LAZY_FLUSH_TIMEOUT))
+				{
+					requests[req->mHost].insert(req);
+				}
 			}
 		}
-	}
-	}
+	}																	// -Mfnq
 
 	for (work_request_map_t::iterator iter1 = requests.begin();
 		 iter1 != requests.end(); ++iter1)
@@ -2460,9 +2878,9 @@ void LLTextureFetch::sendRequestListToSimulators()
 				if (req->mSentRequest != LLTextureFetchWorker::SENT_SIM)
 				{
 					// Initialize packet data based on data read from cache
-					req->lockWorkMutex();
+					req->lockWorkMutex();								// +Mw
 					req->setupPacketData();
-					req->unlockWorkMutex();
+					req->unlockWorkMutex();								// -Mw		
 				}
 				if (0 == sim_request_count)
 				{
@@ -2491,12 +2909,12 @@ void LLTextureFetch::sendRequestListToSimulators()
 					mTextureInfo.setRequestType(req->mID, LLTextureInfoDetails::REQUEST_TYPE_UDP);
 				}
 
-				req->lockWorkMutex();
+				req->lockWorkMutex();									// +Mw
 				req->mSentRequest = LLTextureFetchWorker::SENT_SIM;
 				req->mSimRequestedDiscard = req->mDesiredDiscard;
 				req->mRequestedPriority = req->mImagePriority;
 				req->mRequestedTimer.reset();
-				req->unlockWorkMutex();
+				req->unlockWorkMutex();									// -Mw
 				sim_request_count++;
 				if (sim_request_count >= IMAGES_PER_REQUEST)
 				{
@@ -2517,55 +2935,57 @@ void LLTextureFetch::sendRequestListToSimulators()
 	
 	// Send cancelations
 	{
-	LLMutexLock lock2(&mNetworkQueueMutex);
-	if (gMessageSystem && !mCancelQueue.empty())
-	{
-		for (cancel_queue_t::iterator iter1 = mCancelQueue.begin();
-			 iter1 != mCancelQueue.end(); ++iter1)
+		LLMutexLock lock2(&mNetworkQueueMutex);							// +Mfnq
+		if (gMessageSystem && !mCancelQueue.empty())
 		{
-			LLHost host = iter1->first;
-			if (host == LLHost::invalid)
+			for (cancel_queue_t::iterator iter1 = mCancelQueue.begin();
+				 iter1 != mCancelQueue.end(); ++iter1)
 			{
-				host = gAgent.getRegionHost();
-			}
-			S32 request_count = 0;
-			for (queue_t::iterator iter2 = iter1->second.begin();
-				 iter2 != iter1->second.end(); ++iter2)
-			{
-				if (0 == request_count)
+				LLHost host = iter1->first;
+				if (host == LLHost::invalid)
 				{
-					gMessageSystem->newMessageFast(_PREHASH_RequestImage);
-					gMessageSystem->nextBlockFast(_PREHASH_AgentData);
-					gMessageSystem->addUUIDFast(_PREHASH_AgentID, gAgent.getID());
-					gMessageSystem->addUUIDFast(_PREHASH_SessionID, gAgent.getSessionID());
+					host = gAgent.getRegionHost();
 				}
-				gMessageSystem->nextBlockFast(_PREHASH_RequestImage);
-				gMessageSystem->addUUIDFast(_PREHASH_Image, *iter2);
-				gMessageSystem->addS8Fast(_PREHASH_DiscardLevel, -1);
-				gMessageSystem->addF32Fast(_PREHASH_DownloadPriority, 0);
-				gMessageSystem->addU32Fast(_PREHASH_Packet, 0);
-				gMessageSystem->addU8Fast(_PREHASH_Type, 0);
+				S32 request_count = 0;
+				for (queue_t::iterator iter2 = iter1->second.begin();
+					 iter2 != iter1->second.end(); ++iter2)
+				{
+					if (0 == request_count)
+					{
+						gMessageSystem->newMessageFast(_PREHASH_RequestImage);
+						gMessageSystem->nextBlockFast(_PREHASH_AgentData);
+						gMessageSystem->addUUIDFast(_PREHASH_AgentID, gAgent.getID());
+						gMessageSystem->addUUIDFast(_PREHASH_SessionID, gAgent.getSessionID());
+					}
+					gMessageSystem->nextBlockFast(_PREHASH_RequestImage);
+					gMessageSystem->addUUIDFast(_PREHASH_Image, *iter2);
+					gMessageSystem->addS8Fast(_PREHASH_DiscardLevel, -1);
+					gMessageSystem->addF32Fast(_PREHASH_DownloadPriority, 0);
+					gMessageSystem->addU32Fast(_PREHASH_Packet, 0);
+					gMessageSystem->addU8Fast(_PREHASH_Type, 0);
 // 				llinfos << "CANCELING IMAGE REQUEST: " << (*iter2) << llendl;
 
-				request_count++;
-				if (request_count >= IMAGES_PER_REQUEST)
+					request_count++;
+					if (request_count >= IMAGES_PER_REQUEST)
+					{
+						gMessageSystem->sendSemiReliable(host, NULL, NULL);
+						request_count = 0;
+					}
+				}
+				if (request_count > 0 && request_count < IMAGES_PER_REQUEST)
 				{
 					gMessageSystem->sendSemiReliable(host, NULL, NULL);
-					request_count = 0;
 				}
 			}
-			if (request_count > 0 && request_count < IMAGES_PER_REQUEST)
-			{
-				gMessageSystem->sendSemiReliable(host, NULL, NULL);
-			}
+			mCancelQueue.clear();
 		}
-		mCancelQueue.clear();
-	}
-	}
+	}																	// -Mfnq
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
+// Threads:  T*
+// Locks:  Mw
 bool LLTextureFetchWorker::insertPacket(S32 index, U8* data, S32 size)
 {
 	mRequestedTimer.reset();
@@ -2598,6 +3018,7 @@ bool LLTextureFetchWorker::insertPacket(S32 index, U8* data, S32 size)
 	return true;
 }
 
+// Threads:  T*
 bool LLTextureFetch::receiveImageHeader(const LLHost& host, const LLUUID& id, U8 codec, U16 packets, U32 totalbytes,
 										U16 data_size, U8* data)
 {
@@ -2632,14 +3053,14 @@ bool LLTextureFetch::receiveImageHeader(const LLHost& host, const LLUUID& id, U8
 	}
 	if (!res)
 	{
+		mNetworkQueueMutex.lock();										// +Mfnq
 		++mBadPacketCount;
-		mNetworkQueueMutex.lock() ;
 		mCancelQueue[host].insert(id);
-		mNetworkQueueMutex.unlock() ;
+		mNetworkQueueMutex.unlock();									// -Mfnq 
 		return false;
 	}
 
-	worker->lockWorkMutex();
+	worker->lockWorkMutex();											// +Mw
 
 	//	Copy header data into image object
 	worker->mImageCodec = codec;
@@ -2650,10 +3071,12 @@ bool LLTextureFetch::receiveImageHeader(const LLHost& host, const LLUUID& id, U8
 	res = worker->insertPacket(0, data, data_size);
 	worker->setPriority(LLWorkerThread::PRIORITY_HIGH | worker->mWorkPriority);
 	worker->mState = LLTextureFetchWorker::LOAD_FROM_SIMULATOR;
-	worker->unlockWorkMutex();
+	worker->unlockWorkMutex();											// -Mw
 	return res;
 }
 
+
+// Threads:  T*
 bool LLTextureFetch::receiveImagePacket(const LLHost& host, const LLUUID& id, U16 packet_num, U16 data_size, U8* data)
 {
 	LLTextureFetchWorker* worker = getWorker(id);
@@ -2678,14 +3101,14 @@ bool LLTextureFetch::receiveImagePacket(const LLHost& host, const LLUUID& id, U1
 	}
 	if (!res)
 	{
+		mNetworkQueueMutex.lock();										// +Mfnq
 		++mBadPacketCount;
-		mNetworkQueueMutex.lock() ;
 		mCancelQueue[host].insert(id);
-		mNetworkQueueMutex.unlock() ;
+		mNetworkQueueMutex.unlock();									// -Mfnq
 		return false;
 	}
 
-	worker->lockWorkMutex();
+	worker->lockWorkMutex();											// +Mw
 	
 	res = worker->insertPacket(packet_num, data, data_size);
 	
@@ -2702,7 +3125,7 @@ bool LLTextureFetch::receiveImagePacket(const LLHost& host, const LLUUID& id, U1
 		removeFromNetworkQueue(worker, true); // failsafe
 	}
 
-	if(packet_num >= (worker->mTotalPackets - 1))
+	if (packet_num >= (worker->mTotalPackets - 1))
 	{
 		static LLCachedControl<bool> log_to_viewer_log(gSavedSettings,"LogTextureDownloadsToViewerLog");
 		static LLCachedControl<bool> log_to_sim(gSavedSettings,"LogTextureDownloadsToSimulator");
@@ -2714,12 +3137,14 @@ bool LLTextureFetch::receiveImagePacket(const LLHost& host, const LLUUID& id, U1
 			mTextureInfo.setRequestCompleteTimeAndLog(id, timeNow);
 		}
 	}
-	worker->unlockWorkMutex();
+	worker->unlockWorkMutex();											// -Mw
 
 	return res;
 }
 
 //////////////////////////////////////////////////////////////////////////////
+
+// Threads:  T*
 BOOL LLTextureFetch::isFromLocalCache(const LLUUID& id)
 {
 	BOOL from_cache = FALSE ;
@@ -2727,14 +3152,15 @@ BOOL LLTextureFetch::isFromLocalCache(const LLUUID& id)
 	LLTextureFetchWorker* worker = getWorker(id);
 	if (worker)
 	{
-		worker->lockWorkMutex() ;
-		from_cache = worker->mInLocalCache ;
-		worker->unlockWorkMutex() ;
+		worker->lockWorkMutex();										// +Mw
+		from_cache = worker->mInLocalCache;
+		worker->unlockWorkMutex();										// -Mw
 	}
 
 	return from_cache ;
 }
 
+// Threads:  T*
 S32 LLTextureFetch::getFetchState(const LLUUID& id, F32& data_progress_p, F32& requested_priority_p,
 								  U32& fetch_priority_p, F32& fetch_dtime_p, F32& request_dtime_p, bool& can_use_http)
 {
@@ -2748,7 +3174,7 @@ S32 LLTextureFetch::getFetchState(const LLUUID& id, F32& data_progress_p, F32& r
 	LLTextureFetchWorker* worker = getWorker(id);
 	if (worker && worker->haveWork())
 	{
-		worker->lockWorkMutex();
+		worker->lockWorkMutex();										// +Mw
 		state = worker->mState;
 		fetch_dtime = worker->mFetchTimer.getElapsedTimeF32();
 		request_dtime = worker->mRequestedTimer.getElapsedTimeF32();
@@ -2775,7 +3201,7 @@ S32 LLTextureFetch::getFetchState(const LLUUID& id, F32& data_progress_p, F32& r
 		}
 		fetch_priority = worker->getPriority();
 		can_use_http = worker->getCanUseHTTP() ;
-		worker->unlockWorkMutex();
+		worker->unlockWorkMutex();										// -Mw
 	}
 	data_progress_p = data_progress;
 	requested_priority_p = requested_priority;
@@ -2799,12 +3225,171 @@ void LLTextureFetch::dump()
 				<< " STATE: " << worker->sStateDescs[worker->mState]
 				<< llendl;
 	}
+
+	llinfos << "LLTextureFetch ACTIVE_HTTP:" << llendl;
+	for (queue_t::const_iterator iter(mHTTPTextureQueue.begin());
+		 mHTTPTextureQueue.end() != iter;
+		 ++iter)
+	{
+		llinfos << " ID: " << (*iter) << llendl;
+	}
+
+	llinfos << "LLTextureFetch WAIT_HTTP_RESOURCE:" << llendl;
+	for (wait_http_res_queue_t::const_iterator iter(mHttpWaitResource.begin());
+		 mHttpWaitResource.end() != iter;
+		 ++iter)
+	{
+		llinfos << " ID: " << (*iter) << llendl;
+	}
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+// HTTP Resource Waiting Methods
+
+// Threads:  Ttf
+void LLTextureFetch::addHttpWaiter(const LLUUID & tid)
+{
+	mNetworkQueueMutex.lock();											// +Mfnq
+	mHttpWaitResource.insert(tid);
+	mNetworkQueueMutex.unlock();										// -Mfnq
+}
+
+// Threads:  Ttf
+void LLTextureFetch::removeHttpWaiter(const LLUUID & tid)
+{
+	mNetworkQueueMutex.lock();											// +Mfnq
+	wait_http_res_queue_t::iterator iter(mHttpWaitResource.find(tid));
+	if (mHttpWaitResource.end() != iter)
+	{
+		mHttpWaitResource.erase(iter);
+	}
+	mNetworkQueueMutex.unlock();										// -Mfnq
+}
+
+// Threads:  Ttf
+// Locks:  -Mw (must not hold any worker when called)
+void LLTextureFetch::releaseHttpWaiters()
+{
+	if (mHttpSemaphore < HTTP_REQUESTS_IN_QUEUE_LOW_WATER)
+		return;
+
+	// Quickly make a copy of all the LLUIDs.  Get off the
+	// mutex as early as possible.
+	typedef std::vector<LLUUID> uuid_vec_t;
+	uuid_vec_t tids;
+
+	{
+		LLMutexLock lock(&mNetworkQueueMutex);							// +Mfnq
+
+		if (mHttpWaitResource.empty())
+			return;
+
+		const size_t limit(mHttpWaitResource.size());
+		tids.reserve(limit);
+		for (wait_http_res_queue_t::iterator iter(mHttpWaitResource.begin());
+			 mHttpWaitResource.end() != iter;
+			 ++iter)
+		{
+			tids.push_back(*iter);
+		}
+	}																	// -Mfnq
+
+	// Now lookup the UUUIDs to find valid requests and sort
+	// them in priority order, highest to lowest.
+	typedef std::set<LLTextureFetchWorker *, LLTextureFetchWorker::Compare> worker_set_t;
+	worker_set_t tids2;
+
+	for (uuid_vec_t::const_iterator iter(tids.begin());
+		 tids.end() != iter;
+		 ++iter)
+	{
+		LLTextureFetchWorker * worker(getWorker(* iter));
+		if (worker)
+		{
+			tids2.insert(worker);
+		}
+	}
+	tids.clear();
+
+	// Release workers up to the high water mark.  Since we aren't
+	// holding any locks at this point, we can be in competition
+	// with other callers.  Do defensive things like getting
+	// refreshed counts of requests and checking if someone else
+	// has moved any worker state around....
+	for (worker_set_t::iterator iter2(tids2.begin());
+		 tids2.end() != iter2 && mHttpSemaphore > 0;
+		 ++iter2)
+	{
+		LLTextureFetchWorker * worker(* iter2);
+
+		worker->lockWorkMutex();										// +Mw
+		if (LLTextureFetchWorker::WAIT_HTTP_RESOURCE2 != worker->mState)
+		{
+			worker->unlockWorkMutex();									// -Mw
+			continue;
+		}
+
+		worker->mState = LLTextureFetchWorker::SEND_HTTP_REQ;
+		worker->setPriority(LLWorkerThread::PRIORITY_HIGH | worker->mWorkPriority);
+		worker->acquireHttpSemaphore();
+		worker->unlockWorkMutex();										// -Mw
+
+		removeHttpWaiter(worker->mID);
+	}
+}
+
+// Threads:  T*
+void LLTextureFetch::cancelHttpWaiters()
+{
+	mNetworkQueueMutex.lock();											// +Mfnq
+	mHttpWaitResource.clear();
+	mNetworkQueueMutex.unlock();										// -Mfnq
+}
+
+// Threads:  T*
+int LLTextureFetch::getHttpWaitersCount()
+{
+	mNetworkQueueMutex.lock();											// +Mfnq
+	int ret(mHttpWaitResource.size());
+	mNetworkQueueMutex.unlock();										// -Mfnq
+	return ret;
+}
+
+
+// Threads:  T*
+void LLTextureFetch::updateStateStats(U32 cache_read, U32 cache_write, U32 res_wait)
+{
+	LLMutexLock lock(&mQueueMutex);										// +Mfq
+
+	mTotalCacheReadCount += cache_read;
+	mTotalCacheWriteCount += cache_write;
+	mTotalResourceWaitCount += res_wait;
+}																		// -Mfq
+
+
+// Threads:  T*
+void LLTextureFetch::getStateStats(U32 * cache_read, U32 * cache_write, U32 * res_wait)
+{
+	U32 ret1(0U), ret2(0U), ret3(0U);
+	
+	{
+		LLMutexLock lock(&mQueueMutex);									// +Mfq
+		ret1 = mTotalCacheReadCount;
+		ret2 = mTotalCacheWriteCount;
+		ret3 = mTotalResourceWaitCount;
+	}																	// -Mfq
+	
+	*cache_read = ret1;
+	*cache_write = ret2;
+	*res_wait = ret3;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
 // cross-thread command methods
 
+// Threads:  T*
 void LLTextureFetch::commandSetRegion(U64 region_handle)
 {
 	TFReqSetRegion * req = new TFReqSetRegion(region_handle);
@@ -2812,6 +3397,7 @@ void LLTextureFetch::commandSetRegion(U64 region_handle)
 	cmdEnqueue(req);
 }
 
+// Threads:  T*
 void LLTextureFetch::commandSendMetrics(const std::string & caps_url,
 										const LLUUID & session_id,
 										const LLUUID & agent_id,
@@ -2822,6 +3408,7 @@ void LLTextureFetch::commandSendMetrics(const std::string & caps_url,
 	cmdEnqueue(req);
 }
 
+// Threads:  T*
 void LLTextureFetch::commandDataBreak()
 {
 	// The pedantically correct way to implement this is to create a command
@@ -2832,30 +3419,33 @@ void LLTextureFetch::commandDataBreak()
 	LLTextureFetch::svMetricsDataBreak = true;
 }
 
+// Threads:  T*
 void LLTextureFetch::cmdEnqueue(TFRequest * req)
 {
-	lockQueue();
+	lockQueue();														// +Mfq
 	mCommands.push_back(req);
-	unlockQueue();
+	unlockQueue();														// -Mfq
 
 	unpause();
 }
 
+// Threads:  T*
 LLTextureFetch::TFRequest * LLTextureFetch::cmdDequeue()
 {
 	TFRequest * ret = 0;
 	
-	lockQueue();
+	lockQueue();														// +Mfq
 	if (! mCommands.empty())
 	{
 		ret = mCommands.front();
 		mCommands.erase(mCommands.begin());
 	}
-	unlockQueue();
+	unlockQueue();														// -Mfq
 
 	return ret;
 }
 
+// Threads:  Ttf
 void LLTextureFetch::cmdDoWork()
 {
 	if (mDebugPause)
@@ -2879,6 +3469,37 @@ void LLTextureFetch::cmdDoWork()
 namespace
 {
 
+
+// Example of a simple notification handler for metrics
+// delivery notification.  Earlier versions of the code used
+// a Responder that tried harder to detect delivery breaks
+// but it really isn't that important.  If someone wants to
+// revisit that effort, here is a place to start.
+class AssetReportHandler : public LLCore::HttpHandler
+{
+public:
+
+	// Threads:  Ttf
+	virtual void onCompleted(LLCore::HttpHandle handle, LLCore::HttpResponse * response)
+	{
+		LLCore::HttpStatus status(response->getStatus());
+
+		if (status)
+		{
+			LL_WARNS("Texture") << "Successfully delivered asset metrics to grid."
+								<< LL_ENDL;
+		}
+		else
+		{
+			LL_WARNS("Texture") << "Error delivering asset metrics to grid.  Reason:  "
+								<< status.toString() << LL_ENDL;
+		}
+	}
+}; // end class AssetReportHandler
+
+AssetReportHandler stats_handler;
+
+
 /**
  * Implements the 'Set Region' command.
  *
@@ -2909,73 +3530,9 @@ TFReqSendMetrics::~TFReqSendMetrics()
 bool
 TFReqSendMetrics::doWork(LLTextureFetch * fetcher)
 {
-	/*
-	 * HTTP POST responder.  Doesn't do much but tries to
-	 * detect simple breaks in recording the metrics stream.
-	 *
-	 * The 'volatile' modifiers don't indicate signals,
-	 * mmap'd memory or threads, really.  They indicate that
-	 * the referenced data is part of a pseudo-closure for
-	 * this responder rather than being required for correct
-	 * operation.
-     *
-     * We don't try very hard with the POST request.  We give
-     * it one shot and that's more-or-less it.  With a proper
-     * refactoring of the LLQueuedThread usage, these POSTs
-     * could be put in a request object and made more reliable.
-	 */
-	class lcl_responder : public LLCurl::Responder
-	{
-	public:
-		lcl_responder(LLTextureFetch * fetcher,
-					  S32 expected_sequence,
-                      volatile const S32 & live_sequence,
-                      volatile bool & reporting_break,
-					  volatile bool & reporting_started)
-			: LLCurl::Responder(),
-			  mFetcher(fetcher),
-              mExpectedSequence(expected_sequence),
-              mLiveSequence(live_sequence),
-			  mReportingBreak(reporting_break),
-			  mReportingStarted(reporting_started)
-			{
-                mFetcher->incrCurlPOSTCount();
-            }
-        
-        ~lcl_responder()
-            {
-                mFetcher->decrCurlPOSTCount();
-            }
-
-		// virtual
-		void error(U32 status_num, const std::string & reason)
-			{
-                if (mLiveSequence == mExpectedSequence)
-                {
-                    mReportingBreak = true;
-                }
-				LL_WARNS("Texture") << "Break in metrics stream due to POST failure to metrics collection service.  Reason:  "
-									<< reason << LL_ENDL;
-			}
-
-		// virtual
-		void result(const LLSD & content)
-			{
-                if (mLiveSequence == mExpectedSequence)
-                {
-                    mReportingBreak = false;
-                    mReportingStarted = true;
-                }
-			}
-
-	private:
-		LLTextureFetch * mFetcher;
-        S32 mExpectedSequence;
-        volatile const S32 & mLiveSequence;
-		volatile bool & mReportingBreak;
-		volatile bool & mReportingStarted;
-
-	}; // class lcl_responder
+	static const U32 report_priority(1);
+	static const int report_policy_class(LLCore::HttpRequest::DEFAULT_POLICY_ID);
+	static LLCore::HttpHandler * const handler(fetcher->isQAMode() || true ? &stats_handler : NULL);
 	
 	if (! gViewerAssetStatsThread1)
 		return true;
@@ -3003,21 +3560,26 @@ TFReqSendMetrics::doWork(LLTextureFetch * fetcher)
 	// Update sequence number
 	if (S32_MAX == ++report_sequence)
 		report_sequence = 0;
-
+	reporting_started = true;
+	
 	// Limit the size of the stats report if necessary.
 	merged_llsd["truncated"] = truncate_viewer_metrics(10, merged_llsd);
 
 	if (! mCapsURL.empty())
 	{
-		LLCurlRequest::headers_t headers;
-		fetcher->getCurlRequest().post(mCapsURL,
-									   headers,
-									   merged_llsd,
-									   new lcl_responder(fetcher,
-														 report_sequence,
-                                                         report_sequence,
-                                                         LLTextureFetch::svMetricsDataBreak,
-														 reporting_started));
+		LLCore::BufferArray * ba = new LLCore::BufferArray;
+		LLCore::BufferArrayStream bas(ba);
+		LLSDSerialize::toXML(merged_llsd, bas);
+		
+		fetcher->getHttpRequest().requestPost(report_policy_class,
+											  report_priority,
+											  mCapsURL,
+											  ba,
+											  NULL,
+											  fetcher->getMetricsHeaders(),
+											  handler);
+		ba->release();
+		LLTextureFetch::svMetricsDataBreak = false;
 	}
 	else
 	{
@@ -3075,6 +3637,7 @@ truncate_viewer_metrics(int max_regions, LLSD & metrics)
 
 } // end of anonymous namespace
 
+
 ///////////////////////////////////////////////////////////////////////////////////////////
 //Start LLTextureFetchDebugger
 ///////////////////////////////////////////////////////////////////////////////////////////
@@ -3128,47 +3691,13 @@ private:
 	S32 mID;
 };
 
-class LLDebuggerHTTPResponder : public LLCurl::Responder
-{
-public:
-	LLDebuggerHTTPResponder(LLTextureFetchDebugger* debugger, S32 index)
-	: mDebugger(debugger), mIndex(index)
-	{
-	}
-	virtual void completedRaw(U32 status, const std::string& reason,
-							  const LLChannelDescriptors& channels,
-							  const LLIOPipe::buffer_ptr_t& buffer)
-	{
-		bool success = false;
-		bool partial = false;
-		if (HTTP_OK <= status &&  status < HTTP_MULTIPLE_CHOICES)
-		{
-			success = true;
-			if (HTTP_PARTIAL_CONTENT == status) // partial information
-			{
-				partial = true;
-			}
-		}
-		if (!success)
-		{
-			llinfos << "Fetch Debugger : CURL GET FAILED, index = " << mIndex << ", status:" << status << " reason:" << reason << llendl;
-		}
-		mDebugger->callbackHTTP(mIndex, channels, buffer, partial, success);
-	}
-	virtual bool followRedir()
-	{
-		return true;
-	}
-private:
-	LLTextureFetchDebugger* mDebugger;
-	S32 mIndex;
-};
 
 LLTextureFetchDebugger::LLTextureFetchDebugger(LLTextureFetch* fetcher, LLTextureCache* cache, LLImageDecodeThread* imagedecodethread) :
 	mFetcher(fetcher),
 	mTextureCache(cache),
 	mImageDecodeThread(imagedecodethread),
-	mCurlGetRequest(NULL)
+	mHttpHeaders(NULL),
+	mHttpPolicyClass(LLCore::HttpRequest::DEFAULT_POLICY_ID)
 {
 	init();
 }
@@ -3177,6 +3706,11 @@ LLTextureFetchDebugger::~LLTextureFetchDebugger()
 {
 	mFetchingHistory.clear();
 	stopDebug();
+	if (mHttpHeaders)
+	{
+		mHttpHeaders->release();
+		mHttpHeaders = NULL;
+	}
 }
 
 void LLTextureFetchDebugger::init()
@@ -3208,6 +3742,12 @@ void LLTextureFetchDebugger::init()
 	mRefetchedPixels = 0;
 
 	mFreezeHistory = FALSE;
+
+	if (! mHttpHeaders)
+	{
+		mHttpHeaders = new LLCore::HttpHeaders;
+		mHttpHeaders->mHeaders.push_back("Accept: image/x-j2c");
+	}
 }
 
 void LLTextureFetchDebugger::startDebug()
@@ -3283,7 +3823,7 @@ void LLTextureFetchDebugger::stopDebug()
 			{
 				mTextureCache->readComplete(mFetchingHistory[i].mCacheHandle, true);
 			}
-		}	
+ 		}	
 		break;
 	case WRITE_CACHE:
 		for(S32 i = 0 ; i < size; i++)
@@ -3322,6 +3862,7 @@ void LLTextureFetchDebugger::stopDebug()
 void LLTextureFetchDebugger::clearHistory()
 {
 	mFetchingHistory.clear();
+	mHandleToFetchIndex.clear();
 	init();
 }
 
@@ -3466,6 +4007,7 @@ void LLTextureFetchDebugger::debugHTTP()
 		mFetchingHistory[i].mCurlState = FetchEntry::CURL_NOT_DONE;
 		mFetchingHistory[i].mCurlReceivedSize = 0;
 		mFetchingHistory[i].mHTTPFailCount = 0;
+		mFetchingHistory[i].mFormattedImage = NULL;
 	}
 	mNbCurlRequests = 0;
 	mNbCurlCompleted = 0;
@@ -3475,7 +4017,7 @@ void LLTextureFetchDebugger::debugHTTP()
 
 S32 LLTextureFetchDebugger::fillCurlQueue()
 {
-	if (mNbCurlRequests == 24)
+	if (mNbCurlRequests > 20)
 		return mNbCurlRequests;
 	
 	S32 size = mFetchingHistory.size();
@@ -3489,15 +4031,23 @@ S32 LLTextureFetchDebugger::fillCurlQueue()
 		requestedSize = llmax(0,requestedSize);
 		// We request the whole file if the size was set to an absurdly high value (meaning all file)
 		requestedSize = (requestedSize == 33554432 ? 0 : requestedSize);
-		std::vector<std::string> headers;
-		headers.push_back("Accept: image/x-j2c");
-		bool res = mCurlGetRequest->getByteRange(texture_url, headers, 0, requestedSize, new LLDebuggerHTTPResponder(this, i));
-		if (res)
+
+		LLCore::HttpHandle handle = mFetcher->getHttpRequest().requestGetByteRange(mHttpPolicyClass,
+																				   LLWorkerThread::PRIORITY_LOWBITS,
+																				   texture_url,
+																				   0,
+																				   requestedSize,
+																				   NULL,
+																				   mHttpHeaders,
+																				   this);
+		if (LLCORE_HTTP_HANDLE_INVALID != handle)
 		{
+			mHandleToFetchIndex[handle] = i;
+			mFetchingHistory[i].mHttpHandle = handle;
 			mFetchingHistory[i].mCurlState = FetchEntry::CURL_IN_PROGRESS;
 			mNbCurlRequests++;
 			// Hack
-			if (mNbCurlRequests == 24)
+			if (mNbCurlRequests == 40)
 				break;
 		}
 		else 
@@ -3614,8 +4164,8 @@ bool LLTextureFetchDebugger::update()
 		}
 		break;
 	case HTTP_FETCHING:
-		mCurlGetRequest->process();
-		LLCurl::getCurlThread()->update(1);
+		// Do some notifications...
+		mFetcher->getHttpRequest().update(10);
 		if (!fillCurlQueue() && mNbCurlCompleted == mFetchingHistory.size())
 		{
 			mHTTPTime =  mTimer.getElapsedTimeF32() ;
@@ -3649,6 +4199,28 @@ bool LLTextureFetchDebugger::update()
 	return mState == IDLE;
 }
 
+void LLTextureFetchDebugger::onCompleted(LLCore::HttpHandle handle, LLCore::HttpResponse * response)
+{
+	handle_fetch_map_t::iterator iter(mHandleToFetchIndex.find(handle));
+	if (mHandleToFetchIndex.end() == iter)
+	{
+		llinfos << "Fetch Debugger : Couldn't find handle " << handle << " in fetch list." << llendl;
+		return;
+	}
+	
+	S32 fetch_ind(iter->second);
+	mHandleToFetchIndex.erase(iter);
+	if (fetch_ind >= mFetchingHistory.size() || mFetchingHistory[fetch_ind].mHttpHandle != handle)
+	{
+		llinfos << "Fetch Debugger : Handle and fetch object in disagreement.  Punting." << llendl;
+	}
+	else
+	{
+		callbackHTTP(mFetchingHistory[fetch_ind], response);
+		mFetchingHistory[fetch_ind].mHttpHandle = LLCORE_HTTP_HANDLE_INVALID;	// Not valid after notification
+	}
+}
+
 void LLTextureFetchDebugger::callbackCacheRead(S32 id, bool success, LLImageFormatted* image,
 						   S32 imagesize, BOOL islocal)
 {
@@ -3675,50 +4247,60 @@ void LLTextureFetchDebugger::callbackDecoded(S32 id, bool success, LLImageRaw* r
 	}
 }
 
-void LLTextureFetchDebugger::callbackHTTP(S32 id, const LLChannelDescriptors& channels,
-										  const LLIOPipe::buffer_ptr_t& buffer, 
-										  bool partial, bool success)
+void LLTextureFetchDebugger::callbackHTTP(FetchEntry & fetch, LLCore::HttpResponse * response)
 {
+	static const LLCore::HttpStatus par_status(HTTP_PARTIAL_CONTENT);
+	
+	LLCore::HttpStatus status(response->getStatus());
 	mNbCurlRequests--;
-	if (success)
+	if (status)
 	{
-		mFetchingHistory[id].mCurlState = FetchEntry::CURL_DONE;
+		const bool partial(par_status == status);
+		LLCore::BufferArray * ba(response->getBody());	// *Not* holding reference to body
+		
+		fetch.mCurlState = FetchEntry::CURL_DONE;
 		mNbCurlCompleted++;
 
-		S32 data_size = buffer->countAfter(channels.in(), NULL);
-		mFetchingHistory[id].mCurlReceivedSize += data_size;
-		//llinfos << "Fetch Debugger : got results for " << id << ", data_size = " << data_size << ", received = " << mFetchingHistory[id].mCurlReceivedSize << ", requested = " << mFetchingHistory[id].mRequestedSize << ", partial = " << partial << llendl;
-		if ((mFetchingHistory[id].mCurlReceivedSize >= mFetchingHistory[id].mRequestedSize) || !partial || (mFetchingHistory[id].mRequestedSize == 600))
+		S32 data_size = ba ? ba->size() : 0;
+		fetch.mCurlReceivedSize += data_size;
+		//llinfos << "Fetch Debugger : got results for " << fetch.mID << ", data_size = " << data_size << ", received = " << fetch.mCurlReceivedSize << ", requested = " << fetch.mRequestedSize << ", partial = " << partial << llendl;
+		if ((fetch.mCurlReceivedSize >= fetch.mRequestedSize) || !partial || (fetch.mRequestedSize == 600))
 		{
 			U8* d_buffer = (U8*)ALLOCATE_MEM(LLImageBase::getPrivatePool(), data_size);
-			buffer->readAfter(channels.in(), NULL, d_buffer, data_size);
+			if (ba)
+			{
+				ba->read(0, d_buffer, data_size);
+			}
 			
-			llassert_always(mFetchingHistory[id].mFormattedImage.isNull());
+			llassert_always(fetch.mFormattedImage.isNull());
 			{
 				// For now, create formatted image based on extension
-				std::string texture_url = mHTTPUrl + "/?texture_id=" + mFetchingHistory[id].mID.asString().c_str();
+				std::string texture_url = mHTTPUrl + "/?texture_id=" + fetch.mID.asString().c_str();
 				std::string extension = gDirUtilp->getExtension(texture_url);
-				mFetchingHistory[id].mFormattedImage = LLImageFormatted::createFromType(LLImageBase::getCodecFromExtension(extension));
-				if (mFetchingHistory[id].mFormattedImage.isNull())
+				fetch.mFormattedImage = LLImageFormatted::createFromType(LLImageBase::getCodecFromExtension(extension));
+				if (fetch.mFormattedImage.isNull())
 				{
-					mFetchingHistory[id].mFormattedImage = new LLImageJ2C; // default
+					fetch.mFormattedImage = new LLImageJ2C; // default
 				}
 			}
 						
-			mFetchingHistory[id].mFormattedImage->setData(d_buffer, data_size);	
+			fetch.mFormattedImage->setData(d_buffer, data_size);	
 		}
 	}
 	else //failed
 	{
-		mFetchingHistory[id].mHTTPFailCount++;
-		if(mFetchingHistory[id].mHTTPFailCount < 5)
+		llinfos << "Fetch Debugger : CURL GET FAILED,  ID = " << fetch.mID
+				<< ", status: " << status.toHex()
+				<< " reason:  " << status.toString() << llendl;
+		fetch.mHTTPFailCount++;
+		if(fetch.mHTTPFailCount < 5)
 		{
 			// Fetch will have to be redone
-			mFetchingHistory[id].mCurlState = FetchEntry::CURL_NOT_DONE;
+			fetch.mCurlState = FetchEntry::CURL_NOT_DONE;
 		}
 		else //skip
 		{
-			mFetchingHistory[id].mCurlState = FetchEntry::CURL_DONE;
+			fetch.mCurlState = FetchEntry::CURL_DONE;
 			mNbCurlCompleted++;
 		}
 	}