Hash :
ab7457db
Author :
Date :
2025-01-14T11:55:06
Move ResourceMap mHashedResources access to functions Follow up to https://crrev.com/c/6169263 https://chromium-review.googlesource.com/c/angle/angle/+/6169263/comment/43a79fa6_2a24673c/ Moves mHashedResources access out to function calls as this is a fallback that is supposed to be hit very rarely. This makes the likely branch (flat map accessors/modifiers) smaller so they can be easily inlined without adding much bloat. I also moved flat map resize to a function call as it is fairly rare and makes calls and malloc. This further reduces aarch64 .so size by ~12KB (0.2%) and hopefully improves locality a bit (perf tests inconclusive) Also inline Sampler access in ResourceManager which now uses these small inline accessors. Bug: b/383305597 Change-Id: I013eeb27bf619cc9549a977ab92173e799a1466a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6174944 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
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//
// Copyright 2017 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// ResourceMap:
// An optimized resource map which packs the first set of allocated objects into a
// flat array, and then falls back to an unordered map for the higher handle values.
//
#ifndef LIBANGLE_RESOURCE_MAP_H_
#define LIBANGLE_RESOURCE_MAP_H_
#include <mutex>
#include <type_traits>
#include "common/SimpleMutex.h"
#include "common/hash_containers.h"
#include "libANGLE/angletypes.h"
namespace gl
{
// The resource map needs to be internally synchronized for maps that are placed in the share group
// (as opposed to being private to the context) and that are accessed without holding the share
// group lock.
#if defined(ANGLE_ENABLE_SHARE_CONTEXT_LOCK)
using ResourceMapMutex = angle::SimpleMutex;
#else
using ResourceMapMutex = angle::NoOpMutex;
#endif
template <bool NeedsLock = true>
struct SelectResourceMapMutex
{
using type = ResourceMapMutex;
};
template <>
struct SelectResourceMapMutex<false>
{
using type = angle::NoOpMutex;
};
// Analysis of ANGLE's traces as well as Chrome usage reveals the following:
//
// - Buffers: Typical applications use no more than 4000 ids. Very few use over 6000.
// - Textures: Typical applications use no more than 1200 ids. Very few use over 2000.
// - Samplers: Typical applications use no more than 50 ids. Very few use over 100.
// - Shaders and Programs: Typical applications use no more than 500. Very few use over 700.
// - Sync objects: Typical applications use no more than 500. Very few use over 1500.
//
// For all the other shared types, the maximum used id is small (under 100). For
// context-private parts (such as vertex arrays and queries), the id count can be in the
// thousands.
//
// The initial size of the flat resource map is based on the above, rounded up to a multiple of
// 1536. Resource maps that need a lock (kNeedsLock == true) have the maximum flat size identical
// to initial flat size to avoid reallocation. For others, the maps start small and can grow.
template <typename IDType>
struct ResourceMapParams
{
static constexpr size_t kInitialFlatResourcesSize = 192;
// The following are private to the context and don't need a lock:
//
// - Vertex Array Objects
// - Framebuffer Objects
// - Transform Feedback Objects
// - Query Objects
//
// The rest of the maps need a lock. However, only a select few are currently locked as API
// relevant to the rest of the types are protected by the share group lock. As the share group
// lock is removed from more types, the resource map lock needs to be enabled for them.
static constexpr bool kNeedsLock = false;
};
template <>
struct ResourceMapParams<BufferID>
{
static constexpr size_t kInitialFlatResourcesSize = 6144;
static constexpr bool kNeedsLock = true;
};
template <>
struct ResourceMapParams<TextureID>
{
static constexpr size_t kInitialFlatResourcesSize = 1536;
static constexpr bool kNeedsLock = false;
};
template <>
struct ResourceMapParams<ShaderProgramID>
{
static constexpr size_t kInitialFlatResourcesSize = 1536;
static constexpr bool kNeedsLock = false;
};
template <>
struct ResourceMapParams<SyncID>
{
static constexpr size_t kInitialFlatResourcesSize = 1536;
static constexpr bool kNeedsLock = false;
};
// For the purpose of unit testing, |int| is considered private (not needing lock), and
// |unsigned int| is considered shared (needing lock).
template <>
struct ResourceMapParams<unsigned int>
{
static constexpr size_t kInitialFlatResourcesSize = 192;
static constexpr bool kNeedsLock = true;
};
template <typename ResourceType, typename IDType>
class ResourceMap final : angle::NonCopyable
{
public:
ResourceMap();
~ResourceMap();
ANGLE_INLINE ResourceType *query(IDType id) const
{
GLuint handle = GetIDValue(id);
// No need for a lock when accessing the flat map. Either the flat map is static, or
// locking is not needed.
static_assert(!kNeedsLock || kInitialFlatResourcesSize == kFlatResourcesLimit);
if (ANGLE_LIKELY(handle < mFlatResourcesSize))
{
ResourceType *value = mFlatResources[handle];
return (value == InvalidPointer() ? nullptr : value);
}
return findInHashedResources(handle);
}
// Returns true if the handle was reserved. Not necessarily if the resource is created.
bool contains(IDType id) const;
// Returns the element that was at this location.
bool erase(IDType id, ResourceType **resourceOut);
void assign(IDType id, ResourceType *resource);
// Clears the map.
void clear();
using IndexAndResource = std::pair<GLuint, ResourceType *>;
using HashMap = angle::HashMap<GLuint, ResourceType *>;
class Iterator final
{
public:
bool operator==(const Iterator &other) const;
bool operator!=(const Iterator &other) const;
Iterator &operator++();
const IndexAndResource *operator->() const;
const IndexAndResource &operator*() const;
private:
friend class ResourceMap;
Iterator(const ResourceMap &origin,
GLuint flatIndex,
typename HashMap::const_iterator hashIndex,
bool skipNulls);
void updateValue();
const ResourceMap &mOrigin;
GLuint mFlatIndex;
typename HashMap::const_iterator mHashIndex;
IndexAndResource mValue;
bool mSkipNulls;
};
private:
friend class Iterator;
template <typename SameResourceType, typename SameIDType>
friend class UnsafeResourceMapIter;
// null values represent reserved handles.
Iterator begin() const;
Iterator end() const;
Iterator beginWithNull() const;
Iterator endWithNull() const;
// Used by iterators and related functions only (due to lack of thread safety).
GLuint nextResource(size_t flatIndex, bool skipNulls) const;
// constexpr methods cannot contain reinterpret_cast, so we need a static method.
static ResourceType *InvalidPointer();
static constexpr intptr_t kInvalidPointer = static_cast<intptr_t>(-1);
static constexpr bool kNeedsLock = ResourceMapParams<IDType>::kNeedsLock;
using Mutex = typename SelectResourceMapMutex<kNeedsLock>::type;
static constexpr size_t kInitialFlatResourcesSize =
ResourceMapParams<IDType>::kInitialFlatResourcesSize;
// Experimental testing suggests that ~10k is a reasonable upper limit.
static constexpr size_t kFlatResourcesLimit = kNeedsLock ? kInitialFlatResourcesSize : 0x3000;
// Due to the way assign() is implemented, kFlatResourcesLimit / kInitialFlatResourcesSize must
// be a power of 2.
static_assert(kFlatResourcesLimit % kInitialFlatResourcesSize == 0);
static_assert(((kFlatResourcesLimit / kInitialFlatResourcesSize) &
(kFlatResourcesLimit / kInitialFlatResourcesSize - 1)) == 0);
bool containsInHashedResources(GLuint handle) const;
ResourceType *findInHashedResources(GLuint handle) const;
bool eraseFromHashedResources(GLuint handle, ResourceType **resourceOut);
void assignAboveCurrentFlatSize(GLuint handle, ResourceType *resource);
void assignInHashedResources(GLuint handle, ResourceType *resource);
size_t mFlatResourcesSize;
ResourceType **mFlatResources;
// A map of GL objects indexed by object ID.
HashMap mHashedResources;
// mFlatResources is allocated at object creation time, with a default size of
// |kInitialFlatResourcesSize|. This is thread safe, because the allocation is done by the
// first context in the share group. The flat map is allowed to grow up to
// |kFlatResourcesLimit|, but only for maps that don't need a lock (kNeedsLock == false).
//
// For maps that don't need a lock, this mutex is a no-op. For those that do, the mutex is
// taken when allocating / deleting objects, as well as when accessing |mHashedResources|.
// Otherwise, access to the flat map (which never gets reallocated due to
// |kInitialFlatResourcesSize == kFlatResourcesLimit|) is lockless. This latter is possible
// because the application is not allowed to gen/delete and bind the same ID in different
// threads at the same time.
//
// Note that because HandleAllocator is not yet thread-safe, glGen* and glDelete* functions
// cannot be free of the share group mutex yet. To remove the share group mutex from those
// functions, likely the HandleAllocator class should be merged with this class, and the
// necessary insert/erase operations done under this same lock.
mutable Mutex mMutex;
};
// A helper to retrieve the resource map iterators while being explicit that this is not thread
// safe. Usage of iterators are limited to clean up on destruction and capture/replay, neither of
// which can race with other threads in their access to the resource map.
template <typename ResourceType, typename IDType>
class UnsafeResourceMapIter
{
public:
using ResMap = ResourceMap<ResourceType, IDType>;
UnsafeResourceMapIter(const ResMap &resourceMap) : mResourceMap(resourceMap) {}
typename ResMap::Iterator begin() const { return mResourceMap.begin(); }
typename ResMap::Iterator end() const { return mResourceMap.end(); }
typename ResMap::Iterator beginWithNull() const { return mResourceMap.beginWithNull(); }
typename ResMap::Iterator endWithNull() const { return mResourceMap.endWithNull(); }
// Not a constant-time operation, should only be used for verification.
bool empty() const;
private:
const ResMap &mResourceMap;
};
template <typename ResourceType, typename IDType>
ResourceMap<ResourceType, IDType>::ResourceMap()
: mFlatResourcesSize(kInitialFlatResourcesSize),
mFlatResources(new ResourceType *[kInitialFlatResourcesSize])
{
memset(mFlatResources, kInvalidPointer, mFlatResourcesSize * sizeof(mFlatResources[0]));
}
template <typename ResourceType, typename IDType>
ResourceMap<ResourceType, IDType>::~ResourceMap()
{
ASSERT(begin() == end());
delete[] mFlatResources;
}
template <typename ResourceType, typename IDType>
bool ResourceMap<ResourceType, IDType>::containsInHashedResources(GLuint handle) const
{
std::lock_guard<Mutex> lock(mMutex);
return mHashedResources.find(handle) != mHashedResources.end();
}
template <typename ResourceType, typename IDType>
ResourceType *ResourceMap<ResourceType, IDType>::findInHashedResources(GLuint handle) const
{
std::lock_guard<Mutex> lock(mMutex);
auto it = mHashedResources.find(handle);
// Note: it->second can also be nullptr, so nullptr check doesn't work for "contains"
return (it == mHashedResources.end() ? nullptr : it->second);
}
template <typename ResourceType, typename IDType>
bool ResourceMap<ResourceType, IDType>::eraseFromHashedResources(GLuint handle,
ResourceType **resourceOut)
{
std::lock_guard<Mutex> lock(mMutex);
auto it = mHashedResources.find(handle);
if (it == mHashedResources.end())
{
return false;
}
*resourceOut = it->second;
mHashedResources.erase(it);
return true;
}
template <typename ResourceType, typename IDType>
ANGLE_INLINE bool ResourceMap<ResourceType, IDType>::contains(IDType id) const
{
GLuint handle = GetIDValue(id);
if (ANGLE_LIKELY(handle < mFlatResourcesSize))
{
return mFlatResources[handle] != InvalidPointer();
}
return containsInHashedResources(handle);
}
template <typename ResourceType, typename IDType>
bool ResourceMap<ResourceType, IDType>::erase(IDType id, ResourceType **resourceOut)
{
GLuint handle = GetIDValue(id);
if (ANGLE_LIKELY(handle < mFlatResourcesSize))
{
auto &value = mFlatResources[handle];
if (value == InvalidPointer())
{
return false;
}
*resourceOut = value;
value = InvalidPointer();
return true;
}
return eraseFromHashedResources(handle, resourceOut);
}
template <typename ResourceType, typename IDType>
void ResourceMap<ResourceType, IDType>::assignAboveCurrentFlatSize(GLuint handle,
ResourceType *resource)
{
if (ANGLE_LIKELY(handle < kFlatResourcesLimit))
{
// No need for a lock as the flat map never grows when locking is needed.
static_assert(!kNeedsLock || kInitialFlatResourcesSize == kFlatResourcesLimit);
// Use power-of-two.
size_t newSize = mFlatResourcesSize;
while (newSize <= handle)
{
newSize *= 2;
}
ResourceType **oldResources = mFlatResources;
mFlatResources = new ResourceType *[newSize];
memset(&mFlatResources[mFlatResourcesSize], kInvalidPointer,
(newSize - mFlatResourcesSize) * sizeof(mFlatResources[0]));
memcpy(mFlatResources, oldResources, mFlatResourcesSize * sizeof(mFlatResources[0]));
mFlatResourcesSize = newSize;
ASSERT(mFlatResourcesSize <= kFlatResourcesLimit);
delete[] oldResources;
ASSERT(mFlatResourcesSize > handle);
mFlatResources[handle] = resource;
}
else
{
std::lock_guard<Mutex> lock(mMutex);
mHashedResources[handle] = resource;
}
}
template <typename ResourceType, typename IDType>
ANGLE_INLINE void ResourceMap<ResourceType, IDType>::assign(IDType id, ResourceType *resource)
{
GLuint handle = GetIDValue(id);
if (ANGLE_LIKELY(handle < mFlatResourcesSize))
{
mFlatResources[handle] = resource;
}
else
{
assignAboveCurrentFlatSize(handle, resource);
}
}
template <typename ResourceType, typename IDType>
typename ResourceMap<ResourceType, IDType>::Iterator ResourceMap<ResourceType, IDType>::begin()
const
{
return Iterator(*this, nextResource(0, true), mHashedResources.begin(), true);
}
template <typename ResourceType, typename IDType>
typename ResourceMap<ResourceType, IDType>::Iterator ResourceMap<ResourceType, IDType>::end() const
{
return Iterator(*this, static_cast<GLuint>(mFlatResourcesSize), mHashedResources.end(), true);
}
template <typename ResourceType, typename IDType>
typename ResourceMap<ResourceType, IDType>::Iterator
ResourceMap<ResourceType, IDType>::beginWithNull() const
{
return Iterator(*this, nextResource(0, false), mHashedResources.begin(), false);
}
template <typename ResourceType, typename IDType>
typename ResourceMap<ResourceType, IDType>::Iterator
ResourceMap<ResourceType, IDType>::endWithNull() const
{
return Iterator(*this, static_cast<GLuint>(mFlatResourcesSize), mHashedResources.end(), false);
}
template <typename ResourceType, typename IDType>
bool UnsafeResourceMapIter<ResourceType, IDType>::empty() const
{
return begin() == end();
}
template <typename ResourceType, typename IDType>
void ResourceMap<ResourceType, IDType>::clear()
{
// No need for a lock as this is only called on destruction.
memset(mFlatResources, kInvalidPointer, kInitialFlatResourcesSize * sizeof(mFlatResources[0]));
mFlatResourcesSize = kInitialFlatResourcesSize;
mHashedResources.clear();
}
template <typename ResourceType, typename IDType>
GLuint ResourceMap<ResourceType, IDType>::nextResource(size_t flatIndex, bool skipNulls) const
{
// This function is only used by the iterators, access to which is marked by
// UnsafeResourceMapIter. Locking is the responsibility of the caller.
for (size_t index = flatIndex; index < mFlatResourcesSize; index++)
{
if ((mFlatResources[index] != nullptr || !skipNulls) &&
mFlatResources[index] != InvalidPointer())
{
return static_cast<GLuint>(index);
}
}
return static_cast<GLuint>(mFlatResourcesSize);
}
template <typename ResourceType, typename IDType>
// static
ResourceType *ResourceMap<ResourceType, IDType>::InvalidPointer()
{
return reinterpret_cast<ResourceType *>(kInvalidPointer);
}
template <typename ResourceType, typename IDType>
ResourceMap<ResourceType, IDType>::Iterator::Iterator(
const ResourceMap &origin,
GLuint flatIndex,
typename ResourceMap<ResourceType, IDType>::HashMap::const_iterator hashIndex,
bool skipNulls)
: mOrigin(origin), mFlatIndex(flatIndex), mHashIndex(hashIndex), mSkipNulls(skipNulls)
{
updateValue();
}
template <typename ResourceType, typename IDType>
bool ResourceMap<ResourceType, IDType>::Iterator::operator==(const Iterator &other) const
{
return (mFlatIndex == other.mFlatIndex && mHashIndex == other.mHashIndex);
}
template <typename ResourceType, typename IDType>
bool ResourceMap<ResourceType, IDType>::Iterator::operator!=(const Iterator &other) const
{
return !(*this == other);
}
template <typename ResourceType, typename IDType>
typename ResourceMap<ResourceType, IDType>::Iterator &
ResourceMap<ResourceType, IDType>::Iterator::operator++()
{
if (mFlatIndex < static_cast<GLuint>(mOrigin.mFlatResourcesSize))
{
mFlatIndex = mOrigin.nextResource(mFlatIndex + 1, mSkipNulls);
}
else
{
mHashIndex++;
}
updateValue();
return *this;
}
template <typename ResourceType, typename IDType>
const typename ResourceMap<ResourceType, IDType>::IndexAndResource *
ResourceMap<ResourceType, IDType>::Iterator::operator->() const
{
return &mValue;
}
template <typename ResourceType, typename IDType>
const typename ResourceMap<ResourceType, IDType>::IndexAndResource &
ResourceMap<ResourceType, IDType>::Iterator::operator*() const
{
return mValue;
}
template <typename ResourceType, typename IDType>
void ResourceMap<ResourceType, IDType>::Iterator::updateValue()
{
if (mFlatIndex < static_cast<GLuint>(mOrigin.mFlatResourcesSize))
{
mValue.first = mFlatIndex;
mValue.second = mOrigin.mFlatResources[mFlatIndex];
}
else if (mHashIndex != mOrigin.mHashedResources.end())
{
mValue.first = mHashIndex->first;
mValue.second = mHashIndex->second;
}
}
} // namespace gl
#endif // LIBANGLE_RESOURCE_MAP_H_