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Speed up VAOCache cleanup #827

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8 changes: 6 additions & 2 deletions Graphics/GraphicsEngineOpenGL/include/VAOCache.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@
#include <cstring>
#include <vector>
#include <unordered_map>
#include <unordered_set>

#include "GraphicsTypes.h"
#include "Buffer.h"
Expand Down Expand Up @@ -126,8 +127,11 @@ class VAOCache
Threading::SpinLock m_CacheLock;
std::unordered_map<VAOHashKey, GLObjectWrappers::GLVertexArrayObj, VAOHashKey::Hasher> m_Cache;

std::unordered_map<UniqueIdentifier, std::vector<VAOHashKey>> m_PSOToKey;
std::unordered_map<UniqueIdentifier, std::vector<VAOHashKey>> m_BuffToKey;
// One PSO may have thousands of keys, and erasing one must be fast, so use sets.
using VAOHashKeySet = std::unordered_set<VAOHashKey, VAOHashKey::Hasher>;

std::unordered_map<UniqueIdentifier, VAOHashKeySet> m_PSOToKey;
std::unordered_map<UniqueIdentifier, VAOHashKeySet> m_BuffToKey;

// Any draw command fails if no VAO is bound. We will use this empty
// VAO for draw commands with null input layout, such as these that
Expand Down
64 changes: 22 additions & 42 deletions Graphics/GraphicsEngineOpenGL/src/VAOCache.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,8 +29,6 @@

#include "VAOCache.hpp"

#include <unordered_set>

#include "RenderDeviceGLImpl.hpp"
#include "BufferGLImpl.hpp"
#include "PipelineStateGLImpl.hpp"
Expand Down Expand Up @@ -116,55 +114,37 @@ void VAOCache::Clear()

void VAOCache::ClearStaleKeys(const std::vector<VAOHashKey>& StaleKeys)
{
// Collect unique PSOs and buffers used in stale keys.
std::unordered_set<UniqueIdentifier> CandidatePSOs;
std::unordered_set<UniqueIdentifier> CandidateBuffers;
// Erases the key from the set of one PSO or buffer, and the set itself once it is empty.
auto EraseKey = [](std::unordered_map<UniqueIdentifier, VAOHashKeySet>& IdToKeys,
UniqueIdentifier Id,
const VAOHashKey& Key) //
{
const auto it = IdToKeys.find(Id);
// Not found when Id is the destroyed object's, whose set OnDestroyBuffer() or OnDestroyPSO() has
// already erased, or when the key uses the same buffer twice and the first call emptied its set.
if (it == IdToKeys.end())
return;

it->second.erase(Key);
if (it->second.empty())
IdToKeys.erase(it);
};

for (const VAOHashKey& StaleKey : StaleKeys)
{
CandidatePSOs.emplace(StaleKey.PsoUId);
EraseKey(m_PSOToKey, StaleKey.PsoUId, StaleKey);

if (StaleKey.IndexBufferUId != 0)
CandidateBuffers.emplace(StaleKey.IndexBufferUId);
EraseKey(m_BuffToKey, StaleKey.IndexBufferUId, StaleKey);

for (Uint32 SlotMask = StaleKey.UsedSlotsMask; SlotMask != 0;)
{
const Uint32 SlotBit = ExtractLSB(SlotMask);
const Uint32 Slot = PlatformMisc::GetLSB(SlotBit);
VERIFY_EXPR(StaleKey.Streams[Slot].BufferUId >= 0);
CandidateBuffers.emplace(StaleKey.Streams[Slot].BufferUId);
EraseKey(m_BuffToKey, StaleKey.Streams[Slot].BufferUId, StaleKey);
}
}

auto RemoveStaleEntries = [this](const std::unordered_set<UniqueIdentifier>& CandidateIds,
std::unordered_map<UniqueIdentifier, std::vector<VAOHashKey>>& IdToKey) //
{
auto EraseSwap = [](std::vector<VAOHashKey>& Keys, size_t Index) //
{
if (Index != Keys.size() - 1)
std::swap(Keys[Index], Keys.back());
Keys.pop_back();
};

// Delete stale entries that reference dead keys
for (const UniqueIdentifier Id : CandidateIds)
{
const auto it = IdToKey.find(Id);
if (it != IdToKey.end())
{
// This vector may shrink during iteration
auto& Keys = it->second;
for (size_t i = 0; i < Keys.size();)
{
if (m_Cache.find(Keys[i]) == m_Cache.end())
EraseSwap(Keys, i); // There is no more VAO with this key
else
++i;
}
}
}
};
RemoveStaleEntries(CandidatePSOs, m_PSOToKey);
RemoveStaleEntries(CandidateBuffers, m_BuffToKey);
}

VAOCache::VAOHashKey::VAOHashKey(const VAOAttribs& Attribs) :
Expand Down Expand Up @@ -338,12 +318,12 @@ const GLObjectWrappers::GLVertexArrayObj& VAOCache::GetVAO(const VAOAttribs& Att
// New element must be actually inserted
VERIFY(NewElems.second, "New element was not inserted into the cache");
VERIFY_EXPR(Key.PsoUId == Attribs.PSO.GetUniqueID());
m_PSOToKey[Key.PsoUId].push_back(Key);
m_PSOToKey[Key.PsoUId].insert(Key);

if (Attribs.pIndexBuffer)
{
VERIFY_EXPR(Key.IndexBufferUId == Attribs.pIndexBuffer->GetUniqueID());
m_BuffToKey[Key.IndexBufferUId].push_back(Key);
m_BuffToKey[Key.IndexBufferUId].insert(Key);
}

for (Uint32 SlotMask = Key.UsedSlotsMask; SlotMask != 0;)
Expand All @@ -359,7 +339,7 @@ const GLObjectWrappers::GLVertexArrayObj& VAOCache::GetVAO(const VAOAttribs& Att
}
#endif

m_BuffToKey[Key.Streams[Slot].BufferUId].push_back(Key);
m_BuffToKey[Key.Streams[Slot].BufferUId].insert(Key);
}
return NewElems.first->second;
}
Expand Down