fixed things so that trace recordings can be read from even while active

7 files changed, 299 insertions, 102 deletions

diff --git a/indra/llcommon/lltraceaccumulators.cpp b/indra/llcommon/lltraceaccumulators.cpp
index 7d0e63e76a..385d31edd7 100644
--- a/indra/llcommon/lltraceaccumulators.cpp
+++ b/indra/llcommon/lltraceaccumulators.cpp
@@ -155,6 +155,39 @@ void AccumulatorBufferGroup::sync()
 	}
 }
 
+F64 SampleAccumulator::mergeSumsOfSquares(const SampleAccumulator& a, const SampleAccumulator& b)
+{
+	const F64 epsilon = 0.0000001;
+
+	if (a.getSamplingTime() > epsilon && b.getSamplingTime() > epsilon)
+	{
+		// combine variance (and hence standard deviation) of 2 different sized sample groups using
+		// the following formula: http://www.mrc-bsu.cam.ac.uk/cochrane/handbook/chapter_7/7_7_3_8_combining_groups.htm
+		F64 n_1 = a.getSamplingTime(),
+			n_2 = b.getSamplingTime();
+		F64 m_1 = a.getMean(),
+			m_2 = b.getMean();
+		F64 v_1 = a.getSumOfSquares() / a.getSamplingTime(),
+			v_2 = b.getSumOfSquares() / b.getSamplingTime();
+		if (n_1 < epsilon)
+		{
+			return b.getSumOfSquares();
+		}
+		else
+		{
+			return a.getSamplingTime()
+				* ((((n_1 - epsilon) * v_1)
+				+ ((n_2 - epsilon) * v_2)
+				+ (((n_1 * n_2) / (n_1 + n_2))
+				* ((m_1 * m_1) + (m_2 * m_2) - (2.f * m_1 * m_2))))
+				/ (n_1 + n_2 - epsilon));
+		}
+	}
+
+	return a.getSumOfSquares();
+}
+
+
 void SampleAccumulator::addSamples( const SampleAccumulator& other, EBufferAppendType append_type )
 {
 	if (append_type == NON_SEQUENTIAL)
@@ -180,37 +213,8 @@ void SampleAccumulator::addSamples( const SampleAccumulator& other, EBufferAppen
 		if (other.mMin < mMin) { mMin = other.mMin; }
 		if (other.mMax > mMax) { mMax = other.mMax; }
 
-		F64 epsilon = 0.0000001;
+		mSumOfSquares = mergeSumsOfSquares(*this, other);
 
-		if (other.mTotalSamplingTime > epsilon && mTotalSamplingTime > epsilon)
-		{
-			// combine variance (and hence standard deviation) of 2 different sized sample groups using
-			// the following formula: http://www.mrc-bsu.cam.ac.uk/cochrane/handbook/chapter_7/7_7_3_8_combining_groups.htm
-			F64 n_1 = mTotalSamplingTime,
-				n_2 = other.mTotalSamplingTime;
-			F64 m_1 = mMean,
-				m_2 = other.mMean;
-			F64 v_1 = mSumOfSquares / mTotalSamplingTime,
-				v_2 = other.mSumOfSquares / other.mTotalSamplingTime;
-			if (n_1 < epsilon)
-			{
-				mSumOfSquares = other.mSumOfSquares;
-			}
-			else
-			{
-				mSumOfSquares =	mTotalSamplingTime
-					* ((((n_1 - epsilon) * v_1)
-					+ ((n_2 - epsilon) * v_2)
-					+ (((n_1 * n_2) / (n_1 + n_2))
-					* ((m_1 * m_1) + (m_2 * m_2) - (2.f * m_1 * m_2))))
-					/ (n_1 + n_2 - epsilon));
-			}
-
-			F64 weight = mTotalSamplingTime / (mTotalSamplingTime + other.mTotalSamplingTime);
-			mNumSamples += other.mNumSamples;
-			mTotalSamplingTime += other.mTotalSamplingTime;
-			mMean = (mMean * weight) + (other.mMean * (1.0 - weight));
-		}
 		if (append_type == SEQUENTIAL)
 		{
 			mLastValue = other.mLastValue;
@@ -234,6 +238,29 @@ void SampleAccumulator::reset( const SampleAccumulator* other )
 	mTotalSamplingTime = 0;
 }
 
+F64 EventAccumulator::mergeSumsOfSquares(const EventAccumulator& a, const EventAccumulator& b)
+{
+	if (a.mNumSamples && b.mNumSamples)
+	{
+		// combine variance (and hence standard deviation) of 2 different sized sample groups using
+		// the following formula: http://www.mrc-bsu.cam.ac.uk/cochrane/handbook/chapter_7/7_7_3_8_combining_groups.htm
+		F64 n_1 = a.mNumSamples,
+			n_2 = b.mNumSamples;
+		F64 m_1 = a.mMean,
+			m_2 = b.mMean;
+		F64 v_1 = a.mSumOfSquares / a.mNumSamples,
+			v_2 = b.mSumOfSquares / b.mNumSamples;
+		return (F64)a.mNumSamples
+			* ((((n_1 - 1.f) * v_1)
+			+ ((n_2 - 1.f) * v_2)
+			+ (((n_1 * n_2) / (n_1 + n_2))
+			* ((m_1 * m_1) + (m_2 * m_2) - (2.f * m_1 * m_2))))
+			/ (n_1 + n_2 - 1.f));
+	}
+
+	return a.mSumOfSquares;
+}
+
 void EventAccumulator::addSamples( const EventAccumulator& other, EBufferAppendType append_type )
 {
 	if (other.mNumSamples)
@@ -250,20 +277,7 @@ void EventAccumulator::addSamples( const EventAccumulator& other, EBufferAppendT
 			if (other.mMin < mMin) { mMin = other.mMin; }
 			if (other.mMax > mMax) { mMax = other.mMax; }
 
-			// combine variance (and hence standard deviation) of 2 different sized sample groups using
-			// the following formula: http://www.mrc-bsu.cam.ac.uk/cochrane/handbook/chapter_7/7_7_3_8_combining_groups.htm
-			F64 n_1 = (F64)mNumSamples,
-				n_2 = (F64)other.mNumSamples;
-			F64 m_1 = mMean,
-				m_2 = other.mMean;
-			F64 v_1 = mSumOfSquares / mNumSamples,
-				v_2 = other.mSumOfSquares / other.mNumSamples;
-			mSumOfSquares = (F64)mNumSamples
-				* ((((n_1 - 1.f) * v_1)
-				+ ((n_2 - 1.f) * v_2)
-				+ (((n_1 * n_2) / (n_1 + n_2))
-				* ((m_1 * m_1) + (m_2 * m_2) - (2.f * m_1 * m_2))))
-				/ (n_1 + n_2 - 1.f));
+			mSumOfSquares = mergeSumsOfSquares(*this, other);
 
 			F64 weight = (F64)mNumSamples / (F64)(mNumSamples + other.mNumSamples);
 			mNumSamples += other.mNumSamples;
diff --git a/indra/llcommon/lltraceaccumulators.h b/indra/llcommon/lltraceaccumulators.h
index 2971907849..dfa037d7c0 100644
--- a/indra/llcommon/lltraceaccumulators.h
+++ b/indra/llcommon/lltraceaccumulators.h
@@ -276,6 +276,9 @@ namespace LLTrace
 		S32 getSampleCount() const       { return mNumSamples; }
 		bool hasValue() const			 { return mNumSamples > 0; }
 
+		// helper utility to calculate combined sumofsquares total
+		static F64 mergeSumsOfSquares(const EventAccumulator& a, const EventAccumulator& b);
+
 	private:
 		F64	mSum,
 			mLastValue;
@@ -359,10 +362,13 @@ namespace LLTrace
 		F64	getMean() const              { return mMean; }
 		F64 getStandardDeviation() const { return sqrtf(mSumOfSquares / mTotalSamplingTime); }
 		F64 getSumOfSquares() const		 { return mSumOfSquares; }
-		F64SecondsImplicit getSamplingTime() { return mTotalSamplingTime; }
+		F64SecondsImplicit getSamplingTime() const { return mTotalSamplingTime; }
 		S32 getSampleCount() const       { return mNumSamples; }
 		bool hasValue() const            { return mHasValue; }
 
+		// helper utility to calculate combined sumofsquares total
+		static F64 mergeSumsOfSquares(const SampleAccumulator& a, const SampleAccumulator& b);
+
 	private:
 		F64		mSum,
 				mLastValue;
diff --git a/indra/llcommon/lltracerecording.cpp b/indra/llcommon/lltracerecording.cpp
index 5ec7ce56b9..0fd0053240 100644
--- a/indra/llcommon/lltracerecording.cpp
+++ b/indra/llcommon/lltracerecording.cpp
@@ -32,6 +32,11 @@
 #include "lltracethreadrecorder.h"
 #include "llthread.h"
 
+inline F64 lerp(F64 a, F64 b, F64 u) 
+{
+	return a + ((b - a) * u);
+}
+
 namespace LLTrace
 {
 
@@ -43,7 +48,7 @@ extern MemStatHandle gTraceMemStat;
 
 Recording::Recording(EPlayState state) 
 :	mElapsedSeconds(0),
-	mInHandOff(false)
+	mActiveBuffers(NULL)
 {
 	claim_alloc(gTraceMemStat, this);
 	mBuffers = new AccumulatorBufferGroup();
@@ -88,13 +93,20 @@ Recording::~Recording()
 	}
 }
 
+// brings recording to front of recorder stack, with up to date info
 void Recording::update()
 {
 	if (isStarted())
 	{
 		mElapsedSeconds += mSamplingTimer.getElapsedTimeF64();
-		AccumulatorBufferGroup* buffers = mBuffers.write();
-		LLTrace::get_thread_recorder()->bringUpToDate(buffers);
+
+		llassert(mActiveBuffers);
+		if(!mActiveBuffers->isCurrent())
+		{
+			AccumulatorBufferGroup* buffers = mBuffers.write();
+			LLTrace::get_thread_recorder()->deactivate(buffers);
+			mActiveBuffers = LLTrace::get_thread_recorder()->activate(buffers);
+		}
 
 		mSamplingTimer.reset();
 	}
@@ -112,20 +124,19 @@ void Recording::handleStart()
 {
 	mSamplingTimer.reset();
 	mBuffers.setStayUnique(true);
-	LLTrace::get_thread_recorder()->activate(mBuffers.write(), mInHandOff);
-	mInHandOff = false;
+	mActiveBuffers = LLTrace::get_thread_recorder()->activate(mBuffers.write());
 }
 
 void Recording::handleStop()
 {
 	mElapsedSeconds += mSamplingTimer.getElapsedTimeF64();
 	LLTrace::get_thread_recorder()->deactivate(mBuffers.write());
+	mActiveBuffers = NULL;
 	mBuffers.setStayUnique(false);
 }
 
 void Recording::handleSplitTo(Recording& other)
 {
-	other.mInHandOff = true;
 	mBuffers.write()->handOffTo(*other.mBuffers.write());
 }
 
@@ -139,214 +150,378 @@ void Recording::appendRecording( Recording& other )
 
 bool Recording::hasValue(const StatType<TimeBlockAccumulator>& stat)
 {
-	return mBuffers->mStackTimers[stat.getIndex()].hasValue();
+	update();
+	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
+	return accumulator.hasValue() || (active_accumulator && active_accumulator->hasValue());
 }
 
 F64Seconds Recording::getSum(const StatType<TimeBlockAccumulator>& stat)
 {
+	update();
 	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
-	return F64Seconds((F64)(accumulator.mTotalTimeCounter) 
-				/ (F64)LLTrace::BlockTimerStatHandle::countsPerSecond());
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
+	return F64Seconds((F64)(accumulator.mTotalTimeCounter) + (F64)(active_accumulator ? active_accumulator->mTotalTimeCounter : 0))
+				/ (F64)LLTrace::BlockTimerStatHandle::countsPerSecond();
 }
 
 F64Seconds Recording::getSum(const StatType<TimeBlockAccumulator::SelfTimeFacet>& stat)
 {
+	update();
 	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
-	return F64Seconds((F64)(accumulator.mSelfTimeCounter) / (F64)LLTrace::BlockTimerStatHandle::countsPerSecond());
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
+	return F64Seconds((F64)(accumulator.mSelfTimeCounter) + (F64)(active_accumulator ? active_accumulator->mSelfTimeCounter : 0) / (F64)LLTrace::BlockTimerStatHandle::countsPerSecond());
 }
 
 
 S32 Recording::getSum(const StatType<TimeBlockAccumulator::CallCountFacet>& stat)
 {
-	return mBuffers->mStackTimers[stat.getIndex()].mCalls;
+	update();
+	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
+	return accumulator.mCalls + (active_accumulator ? active_accumulator->mCalls : 0);
 }
 
 F64Seconds Recording::getPerSec(const StatType<TimeBlockAccumulator>& stat)
 {
+	update();
 	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
 
-	return F64Seconds((F64)(accumulator.mTotalTimeCounter) 
+	return F64Seconds((F64)(accumulator.mTotalTimeCounter + (active_accumulator ? active_accumulator->mTotalTimeCounter : 0)) 
 				/ ((F64)LLTrace::BlockTimerStatHandle::countsPerSecond() * mElapsedSeconds.value()));
 }
 
 F64Seconds Recording::getPerSec(const StatType<TimeBlockAccumulator::SelfTimeFacet>& stat)
 {
+	update();
 	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
 
-	return F64Seconds((F64)(accumulator.mSelfTimeCounter) 
+	return F64Seconds((F64)(accumulator.mSelfTimeCounter + (active_accumulator ? active_accumulator->mSelfTimeCounter : 0))
 			/ ((F64)LLTrace::BlockTimerStatHandle::countsPerSecond() * mElapsedSeconds.value()));
 }
 
 F32 Recording::getPerSec(const StatType<TimeBlockAccumulator::CallCountFacet>& stat)
 {
-	return (F32)mBuffers->mStackTimers[stat.getIndex()].mCalls / mElapsedSeconds.value();
+	update();
+	const TimeBlockAccumulator& accumulator = mBuffers->mStackTimers[stat.getIndex()];
+	const TimeBlockAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mStackTimers[stat.getIndex()] : NULL;
+	return (F32)(accumulator.mCalls + (active_accumulator ? active_accumulator->mCalls : 0)) / mElapsedSeconds.value();
 }
 
 bool Recording::hasValue(const StatType<MemAccumulator>& stat)
 {
-	return mBuffers->mMemStats[stat.getIndex()].mSize.hasValue();
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return accumulator.mSize.hasValue() || (active_accumulator && active_accumulator->mSize.hasValue() ? active_accumulator->mSize.hasValue() : false);
 }
 
 F64Kilobytes Recording::getMin(const StatType<MemAccumulator>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mSize.getMin());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes(llmin(accumulator.mSize.getMin(), (active_accumulator && active_accumulator->mSize.hasValue() ? active_accumulator->mSize.getMin() : F32_MAX)));
 }
 
 F64Kilobytes Recording::getMean(const StatType<MemAccumulator>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mSize.getMean());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	
+	if (active_accumulator && active_accumulator->mSize.hasValue())
+	{
+		return F64Bytes(lerp(accumulator.mSize.getMean(), active_accumulator->mSize.getMean(), active_accumulator->mSize.getSampleCount() / (accumulator.mSize.getSampleCount() + active_accumulator->mSize.getSampleCount())));
+	}
+	else
+	{
+		return F64Bytes(accumulator.mSize.getMean());
+	}
 }
 
 F64Kilobytes Recording::getMax(const StatType<MemAccumulator>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mSize.getMax());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes(llmax(accumulator.mSize.getMax(), active_accumulator && active_accumulator->mSize.hasValue() ? active_accumulator->mSize.getMax() : F32_MIN));
 }
 
 F64Kilobytes Recording::getStandardDeviation(const StatType<MemAccumulator>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mSize.getStandardDeviation());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	if (active_accumulator && active_accumulator->hasValue())
+	{
+		F64 sum_of_squares = SampleAccumulator::mergeSumsOfSquares(accumulator.mSize, active_accumulator->mSize);
+		return F64Bytes(sqrtf(sum_of_squares / (accumulator.mSize.getSamplingTime().value() + active_accumulator->mSize.getSamplingTime().value())));
+	}
+	else
+	{
+		return F64Bytes(accumulator.mSize.getStandardDeviation());
+	}
 }
 
 F64Kilobytes Recording::getLastValue(const StatType<MemAccumulator>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mSize.getLastValue());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes(active_accumulator ? active_accumulator->mSize.getLastValue() : accumulator.mSize.getLastValue());
 }
 
 bool Recording::hasValue(const StatType<MemAccumulator::AllocationFacet>& stat)
 {
-	return mBuffers->mMemStats[stat.getIndex()].mAllocations.hasValue();
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return accumulator.mAllocations.hasValue() || (active_accumulator ? active_accumulator->mAllocations.hasValue() : false);
 }
 
 F64Kilobytes Recording::getSum(const StatType<MemAccumulator::AllocationFacet>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mAllocations.getSum());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes(accumulator.mAllocations.getSum() + (active_accumulator ? active_accumulator->mAllocations.getSum() : 0));
 }
 
 F64Kilobytes Recording::getPerSec(const StatType<MemAccumulator::AllocationFacet>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mAllocations.getSum() / mElapsedSeconds.value());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes((accumulator.mAllocations.getSum() + (active_accumulator ? active_accumulator->mAllocations.getSum() : 0)) / mElapsedSeconds.value());
 }
 
 S32 Recording::getSampleCount(const StatType<MemAccumulator::AllocationFacet>& stat)
 {
-	return mBuffers->mMemStats[stat.getIndex()].mAllocations.getSampleCount();
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return accumulator.mAllocations.getSampleCount() + (active_accumulator ? active_accumulator->mAllocations.getSampleCount() : 0);
 }
 
 bool Recording::hasValue(const StatType<MemAccumulator::DeallocationFacet>& stat)
 {
-	return mBuffers->mMemStats[stat.getIndex()].mDeallocations.hasValue();
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return accumulator.mDeallocations.hasValue() || (active_accumulator ? active_accumulator->mDeallocations.hasValue() : false);
 }
 
 
 F64Kilobytes Recording::getSum(const StatType<MemAccumulator::DeallocationFacet>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mDeallocations.getSum());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes(accumulator.mDeallocations.getSum() + (active_accumulator ? active_accumulator->mDeallocations.getSum() : 0));
 }
 
 F64Kilobytes Recording::getPerSec(const StatType<MemAccumulator::DeallocationFacet>& stat)
 {
-	return F64Bytes(mBuffers->mMemStats[stat.getIndex()].mDeallocations.getSum() / mElapsedSeconds.value());
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return F64Bytes((accumulator.mDeallocations.getSum() + (active_accumulator ? active_accumulator->mDeallocations.getSum() : 0)) / mElapsedSeconds.value());
 }
 
 S32 Recording::getSampleCount(const StatType<MemAccumulator::DeallocationFacet>& stat)
 {
-	return mBuffers->mMemStats[stat.getIndex()].mDeallocations.getSampleCount();
+	update();
+	const MemAccumulator& accumulator = mBuffers->mMemStats[stat.getIndex()];
+	const MemAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mMemStats[stat.getIndex()] : NULL;
+	return accumulator.mDeallocations.getSampleCount() + (active_accumulator ? active_accumulator->mDeallocations.getSampleCount() : 0);
 }
 
 bool Recording::hasValue(const StatType<CountAccumulator>& stat)
 {
-	return mBuffers->mCounts[stat.getIndex()].hasValue();
+	update();
+	const CountAccumulator& accumulator = mBuffers->mCounts[stat.getIndex()];
+	const CountAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mCounts[stat.getIndex()] : NULL;
+	return accumulator.hasValue() || (active_accumulator ? active_accumulator->hasValue() : false);
 }
 
 F64 Recording::getSum(const StatType<CountAccumulator>& stat)
 {
-	return mBuffers->mCounts[stat.getIndex()].getSum();
-}
-
-F64 Recording::getSum( const StatType<EventAccumulator>& stat)
-{
-	return (F64)mBuffers->mEvents[stat.getIndex()].getSum();
+	update();
+	const CountAccumulator& accumulator = mBuffers->mCounts[stat.getIndex()];
+	const CountAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mCounts[stat.getIndex()] : NULL;
+	return accumulator.getSum() + (active_accumulator ? active_accumulator->getSum() : 0);
 }
 
 F64 Recording::getPerSec( const StatType<CountAccumulator>& stat )
 {
-	F64 sum = mBuffers->mCounts[stat.getIndex()].getSum();
-	return  sum / mElapsedSeconds.value();
+	update();
+	const CountAccumulator& accumulator = mBuffers->mCounts[stat.getIndex()];
+	const CountAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mCounts[stat.getIndex()] : NULL;
+	F64 sum = accumulator.getSum() + (active_accumulator ? active_accumulator->getSum() : 0);
+	return sum / mElapsedSeconds.value();
 }
 
 S32 Recording::getSampleCount( const StatType<CountAccumulator>& stat )
 {
-	return mBuffers->mCounts[stat.getIndex()].getSampleCount();
+	update();
+	const CountAccumulator& accumulator = mBuffers->mCounts[stat.getIndex()];
+	const CountAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mCounts[stat.getIndex()] : NULL;
+	return accumulator.getSampleCount() + (active_accumulator ? active_accumulator->getSampleCount() : 0);
 }
 
 bool Recording::hasValue(const StatType<SampleAccumulator>& stat)
 {
-	return mBuffers->mSamples[stat.getIndex()].hasValue();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+	return accumulator.hasValue() || (active_accumulator && active_accumulator->hasValue());
 }
 
 F64 Recording::getMin( const StatType<SampleAccumulator>& stat )
 {
-	return mBuffers->mSamples[stat.getIndex()].getMin();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+	return llmin(accumulator.getMin(), active_accumulator && active_accumulator->hasValue() ? active_accumulator->getMin() : F32_MAX);
 }
 
 F64 Recording::getMax( const StatType<SampleAccumulator>& stat )
 {
-	return mBuffers->mSamples[stat.getIndex()].getMax();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+	return llmax(accumulator.getMax(), active_accumulator && active_accumulator->hasValue() ? active_accumulator->getMax() : F32_MIN);
 }
 
 F64 Recording::getMean( const StatType<SampleAccumulator>& stat )
 {
-	return mBuffers->mSamples[stat.getIndex()].getMean();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+	if (active_accumulator && active_accumulator->hasValue())
+	{
+		return lerp(accumulator.getMean(), active_accumulator->getMean(), active_accumulator->getSampleCount() / (accumulator.getSampleCount() + active_accumulator->getSampleCount()));
+	}
+	else
+	{
+		return accumulator.getMean();
+	}
 }
 
 F64 Recording::getStandardDeviation( const StatType<SampleAccumulator>& stat )
 {
-	return mBuffers->mSamples[stat.getIndex()].getStandardDeviation();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+
+	if (active_accumulator && active_accumulator->hasValue())
+	{
+		F64 sum_of_squares = SampleAccumulator::mergeSumsOfSquares(accumulator, *active_accumulator);
+		return sqrtf(sum_of_squares / (accumulator.getSamplingTime() + active_accumulator->getSamplingTime()));
+	}
+	else
+	{
+		return accumulator.getStandardDeviation();
+	}
 }
 
 F64 Recording::getLastValue( const StatType<SampleAccumulator>& stat )
 {
-	return mBuffers->mSamples[stat.getIndex()].getLastValue();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+	return (active_accumulator && active_accumulator->hasValue() ? active_accumulator->getLastValue() : accumulator.getLastValue());
 }
 
 S32 Recording::getSampleCount( const StatType<SampleAccumulator>& stat )
 {
-	return mBuffers->mSamples[stat.getIndex()].getSampleCount();
+	update();
+	const SampleAccumulator& accumulator = mBuffers->mSamples[stat.getIndex()];
+	const SampleAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mSamples[stat.getIndex()] : NULL;
+	return accumulator.getSampleCount() + (active_accumulator && active_accumulator->hasValue() ? active_accumulator->getSampleCount() : 0);
 }
 
 bool Recording::hasValue(const StatType<EventAccumulator>& stat)
 {
-	return mBuffers->mEvents[stat.getIndex()].hasValue();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	return accumulator.hasValue() || (active_accumulator && active_accumulator->hasValue());
+}
+
+F64 Recording::getSum( const StatType<EventAccumulator>& stat)
+{
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	return (F64)(accumulator.getSum() + (active_accumulator && active_accumulator->hasValue() ? active_accumulator->getSum() : 0));
 }
 
 F64 Recording::getMin( const StatType<EventAccumulator>& stat )
 {
-	return mBuffers->mEvents[stat.getIndex()].getMin();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	return llmin(accumulator.getMin(), active_accumulator && active_accumulator->hasValue() ? active_accumulator->getMin() : F32_MAX);
 }
 
 F64 Recording::getMax( const StatType<EventAccumulator>& stat )
 {
-	return mBuffers->mEvents[stat.getIndex()].getMax();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	return llmax(accumulator.getMax(), active_accumulator && active_accumulator->hasValue() ? active_accumulator->getMax() : F32_MIN);
 }
 
 F64 Recording::getMean( const StatType<EventAccumulator>& stat )
 {
-	return mBuffers->mEvents[stat.getIndex()].getMean();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	if (active_accumulator && active_accumulator->hasValue())
+	{
+		return lerp(accumulator.getMean(), active_accumulator->getMean(), active_accumulator->getSampleCount() / (accumulator.getSampleCount() + active_accumulator->getSampleCount()));
+	}
+	else
+	{
+		return accumulator.getMean();
+	}
 }
 
 F64 Recording::getStandardDeviation( const StatType<EventAccumulator>& stat )
 {
-	return mBuffers->mEvents[stat.getIndex()].getStandardDeviation();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+
+	if (active_accumulator && active_accumulator->hasValue())
+	{
+		F64 sum_of_squares = EventAccumulator::mergeSumsOfSquares(accumulator, *active_accumulator);
+		return sqrtf(sum_of_squares / (accumulator.getSampleCount() + active_accumulator->getSampleCount()));
+	}
+	else
+	{
+		return accumulator.getStandardDeviation();
+	}
 }
 
 F64 Recording::getLastValue( const StatType<EventAccumulator>& stat )
 {
-	return mBuffers->mEvents[stat.getIndex()].getLastValue();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	return active_accumulator ? active_accumulator->getLastValue() : accumulator.getLastValue();
 }
 
 S32 Recording::getSampleCount( const StatType<EventAccumulator>& stat )
 {
-	return mBuffers->mEvents[stat.getIndex()].getSampleCount();
+	update();
+	const EventAccumulator& accumulator = mBuffers->mEvents[stat.getIndex()];
+	const EventAccumulator* active_accumulator = mActiveBuffers ? &mActiveBuffers->mEvents[stat.getIndex()] : NULL;
+	return accumulator.getSampleCount() + (active_accumulator ? active_accumulator->getSampleCount() : 0);
 }
 
 ///////////////////////////////////////////////////////////////////////
diff --git a/indra/llcommon/lltracerecording.h b/indra/llcommon/lltracerecording.h
index b045aafa11..93ac276e33 100644
--- a/indra/llcommon/lltracerecording.h
+++ b/indra/llcommon/lltracerecording.h
@@ -322,7 +322,7 @@ namespace LLTrace
 		LLTimer											mSamplingTimer;
 		F64Seconds										mElapsedSeconds;
 		LLCopyOnWritePointer<AccumulatorBufferGroup>	mBuffers;
-		bool											mInHandOff;
+		AccumulatorBufferGroup*							mActiveBuffers;
 
 	};
 
diff --git a/indra/llcommon/lltracethreadrecorder.cpp b/indra/llcommon/lltracethreadrecorder.cpp
index 7b7da5343d..a70e94e4b1 100644
--- a/indra/llcommon/lltracethreadrecorder.cpp
+++ b/indra/llcommon/lltracethreadrecorder.cpp
@@ -131,7 +131,7 @@ TimeBlockTreeNode* ThreadRecorder::getTimeBlockTreeNode( S32 index )
 }
 
 
-void ThreadRecorder::activate( AccumulatorBufferGroup* recording, bool from_handoff )
+AccumulatorBufferGroup* ThreadRecorder::activate( AccumulatorBufferGroup* recording)
 {
 	ActiveRecording* active_recording = new ActiveRecording(recording);
 	if (!mActiveRecordings.empty())
@@ -144,6 +144,7 @@ void ThreadRecorder::activate( AccumulatorBufferGroup* recording, bool from_hand
 	mActiveRecordings.push_back(active_recording);
 
 	mActiveRecordings.back()->mPartialRecording.makeCurrent();
+	return &active_recording->mPartialRecording;
 }
 
 ThreadRecorder::active_recording_list_t::iterator ThreadRecorder::bringUpToDate( AccumulatorBufferGroup* recording )
diff --git a/indra/llcommon/lltracethreadrecorder.h b/indra/llcommon/lltracethreadrecorder.h
index c6afcdac80..d30fa15ea7 100644
--- a/indra/llcommon/lltracethreadrecorder.h
+++ b/indra/llcommon/lltracethreadrecorder.h
@@ -47,7 +47,7 @@ namespace LLTrace
 
 		~ThreadRecorder();
 
-		void activate(AccumulatorBufferGroup* recording, bool from_handoff = false);
+		AccumulatorBufferGroup* activate(AccumulatorBufferGroup* recording);
 		void deactivate(AccumulatorBufferGroup* recording);
 		active_recording_list_t::iterator bringUpToDate(AccumulatorBufferGroup* recording);
 
diff --git a/indra/llcommon/tests/lltrace_test.cpp b/indra/llcommon/tests/lltrace_test.cpp
index 8ce509699d..0a9d85ad00 100644
--- a/indra/llcommon/tests/lltrace_test.cpp
+++ b/indra/llcommon/tests/lltrace_test.cpp
@@ -109,8 +109,9 @@ namespace tut
 			at_work.stop();
 			drink_coffee(1, S32VentiCup(1));
 		}
-		after_3pm.stop();
-		all_day.stop();
+		// don't need to stop recordings to get accurate values out of them
+		//after_3pm.stop();
+		//all_day.stop();
 
 		ensure("count stats are counted when recording is active", 
 			at_work.getSum(sCupsOfCoffeeConsumed) == 3