From 78007d2592290582e3b3fbff002376ad0561779f Mon Sep 17 00:00:00 2001
From: Dave Parks <davep@lindenlab.com>
Date: Mon, 27 Sep 2021 22:35:50 +0000
Subject: SL-16088 Fix for stall from many calls to glGenBuffers.

---
 indra/llrender/llvertexbuffer.cpp | 19 +++++++++++++++----
 indra/llrender/llvertexbuffer.h   |  5 ++++-
 2 files changed, 19 insertions(+), 5 deletions(-)

(limited to 'indra/llrender')

diff --git a/indra/llrender/llvertexbuffer.cpp b/indra/llrender/llvertexbuffer.cpp
index b69b644ebc..0449ac392c 100644
--- a/indra/llrender/llvertexbuffer.cpp
+++ b/indra/llrender/llvertexbuffer.cpp
@@ -91,6 +91,8 @@ LLVBOPool LLVertexBuffer::sDynamicIBOPool(GL_DYNAMIC_DRAW_ARB, GL_ELEMENT_ARRAY_
 
 U32 LLVBOPool::sBytesPooled = 0;
 U32 LLVBOPool::sIndexBytesPooled = 0;
+U32 LLVBOPool::sNameIdx = 0;
+U32 LLVBOPool::sNamePool[1024];
 
 std::list<U32> LLVertexBuffer::sAvailableVAOName;
 U32 LLVertexBuffer::sCurVAOName = 1;
@@ -121,15 +123,20 @@ bool LLVertexBuffer::sPreferStreamDraw = false;
 
 U32 LLVBOPool::genBuffer()
 {
-	U32 ret = 0;
+	LL_PROFILE_ZONE_SCOPED
 
-	glGenBuffersARB(1, &ret);
-	
-	return ret;
+	if (sNameIdx == 0)
+	{
+		glGenBuffersARB(1024, sNamePool);
+		sNameIdx = 1024;
+	}
+
+	return sNamePool[--sNameIdx];
 }
 
 void LLVBOPool::deleteBuffer(U32 name)
 {
+	LL_PROFILE_ZONE_SCOPED
 	if (gGLManager.mInited)
 	{
 		LLVertexBuffer::unbind();
@@ -152,6 +159,7 @@ LLVBOPool::LLVBOPool(U32 vboUsage, U32 vboType)
 
 volatile U8* LLVBOPool::allocate(U32& name, U32 size, bool for_seed)
 {
+	LL_PROFILE_ZONE_SCOPED
 	llassert(vbo_block_size(size) == size);
 	
 	volatile U8* ret = NULL;
@@ -267,10 +275,12 @@ void LLVBOPool::release(U32 name, volatile U8* buffer, U32 size)
 
 void LLVBOPool::seedPool()
 {
+	LL_PROFILE_ZONE_SCOPED
 	U32 dummy_name = 0;
 
 	if (mFreeList.size() < LL_VBO_POOL_SEED_COUNT)
 	{
+		LL_PROFILE_ZONE_NAMED("VBOPool Resize");
 		mFreeList.resize(LL_VBO_POOL_SEED_COUNT);
 	}
 
@@ -411,6 +421,7 @@ void LLVertexBuffer::releaseVAOName(U32 name)
 //static
 void LLVertexBuffer::seedPools()
 {
+	LL_PROFILE_ZONE_SCOPED
 	sStreamVBOPool.seedPool();
 	sDynamicVBOPool.seedPool();
 	sDynamicCopyVBOPool.seedPool();
diff --git a/indra/llrender/llvertexbuffer.h b/indra/llrender/llvertexbuffer.h
index dbe1a3687f..1d60970df4 100644
--- a/indra/llrender/llvertexbuffer.h
+++ b/indra/llrender/llvertexbuffer.h
@@ -89,6 +89,9 @@ public:
 	std::vector<record_list_t> mFreeList;
 	std::vector<U32> mMissCount;
 
+	//used to avoid calling glGenBuffers for every VBO creation
+	static U32 sNamePool[1024];
+	static U32 sNameIdx;
 };
 
 
@@ -127,7 +130,7 @@ public:
 	static LLVBOPool sDynamicCopyVBOPool;
 	static LLVBOPool sStreamIBOPool;
 	static LLVBOPool sDynamicIBOPool;
-	
+
 	static std::list<U32> sAvailableVAOName;
 	static U32 sCurVAOName;
 
-- 
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