src/dawn_native/d3d12/ResidencyManagerD3D12.cpp - dawn - Git at Google

 // Copyright 2020 The Dawn Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #include "dawn_native/d3d12/ResidencyManagerD3D12.h"

 #include "dawn_native/d3d12/AdapterD3D12.h"
 #include "dawn_native/d3d12/D3D12Error.h"
 #include "dawn_native/d3d12/DeviceD3D12.h"
 #include "dawn_native/d3d12/Forward.h"
 #include "dawn_native/d3d12/HeapD3D12.h"

 #include "dawn_native/d3d12/d3d12_platform.h"

 namespace dawn_native { namespace d3d12 {

     ResidencyManager::ResidencyManager(Device* device)
         : mDevice(device),
           mResidencyManagementEnabled(
               device->IsToggleEnabled(Toggle::UseD3D12ResidencyManagement)) {
         UpdateVideoMemoryInfo();
     }

     // Increments number of locks on a heap to ensure the heap remains resident.
     MaybeError ResidencyManager::LockHeap(Heap* heap) {
         if (!mResidencyManagementEnabled) {
             return {};
         }

         // Depending on device architecture, the heap may not need tracked.
         if (!ShouldTrackHeap(heap)) {
             return {};
         }

         // If the heap isn't already resident, make it resident.
         if (!heap->IsInResidencyLRUCache() && !heap->IsResidencyLocked()) {
             DAWN_TRY(EnsureCanMakeResident(heap->GetSize()));
             ID3D12Pageable* pageable = heap->GetD3D12Pageable().Get();
             DAWN_TRY(CheckHRESULT(mDevice->GetD3D12Device()->MakeResident(1, &pageable),
                                   "Making a scheduled-to-be-used resource resident in "
                                   "device local memory"));
         }

         // Since we can't evict the heap, it's unnecessary to track the heap in the LRU Cache.
         if (heap->IsInResidencyLRUCache()) {
             heap->RemoveFromList();
         }

         heap->IncrementResidencyLock();

         return {};
     }

     // Decrements number of locks on a heap. When the number of locks becomes zero, the heap is
     // inserted into the LRU cache and becomes eligible for eviction.
     void ResidencyManager::UnlockHeap(Heap* heap) {
         if (!mResidencyManagementEnabled) {
             return;
         }

         // Depending on device architecture, the heap may not need tracked.
         if (!ShouldTrackHeap(heap)) {
             return;
         }

         ASSERT(heap->IsResidencyLocked());
         ASSERT(!heap->IsInResidencyLRUCache());
         heap->DecrementResidencyLock();

         // When all locks have been removed, the resource remains resident and becomes tracked in
         // the LRU.
         if (!heap->IsResidencyLocked()) {
             mLRUCache.Append(heap);
         }
     }

     // Allows an application component external to Dawn to cap Dawn's residency budget to prevent
     // competition for device local memory. Returns the amount of memory reserved, which may be less
     // that the requested reservation when under pressure.
     uint64_t ResidencyManager::SetExternalMemoryReservation(uint64_t requestedReservationSize) {
         mVideoMemoryInfo.externalRequest = requestedReservationSize;
         UpdateVideoMemoryInfo();
         return mVideoMemoryInfo.externalReservation;
     }

     void ResidencyManager::UpdateVideoMemoryInfo() {
         if (!mResidencyManagementEnabled) {
             return;
         }

         DXGI_QUERY_VIDEO_MEMORY_INFO queryVideoMemoryInfo;
         ToBackend(mDevice->GetAdapter())
             ->GetHardwareAdapter()
             ->QueryVideoMemoryInfo(0, DXGI_MEMORY_SEGMENT_GROUP_LOCAL, &queryVideoMemoryInfo);

         // The video memory budget provided by QueryVideoMemoryInfo is defined by the operating
         // system, and may be lower than expected in certain scenarios. Under memory pressure, we
         // cap the external reservation to half the available budget, which prevents the external
         // component from consuming a disproportionate share of memory and ensures that Dawn can
         // continue to make forward progress. Note the choice to halve memory is arbitrarily chosen
         // and subject to future experimentation.
         mVideoMemoryInfo.externalReservation =
             std::min(queryVideoMemoryInfo.Budget / 2, mVideoMemoryInfo.externalRequest);

         mVideoMemoryInfo.dawnUsage =
             queryVideoMemoryInfo.CurrentUsage - mVideoMemoryInfo.externalReservation;

         // If we're restricting the budget for testing, leave the budget as is.
         if (mRestrictBudgetForTesting) {
             return;
         }

         // We cap Dawn's budget to 95% of the provided budget. Leaving some budget unused
         // decreases fluctuations in the operating-system-defined budget, which improves stability
         // for both Dawn and other applications on the system. Note the value of 95% is arbitrarily
         // chosen and subject to future experimentation.
         static constexpr float kBudgetCap = 0.95;
         mVideoMemoryInfo.dawnBudget =
             (queryVideoMemoryInfo.Budget - mVideoMemoryInfo.externalReservation) * kBudgetCap;
     }

     // Removes from the LRU and returns the least recently used heap when possible. Returns nullptr
     // when nothing further can be evicted.
     ResultOrError<Heap*> ResidencyManager::RemoveSingleEntryFromLRU() {
         ASSERT(!mLRUCache.empty());
         Heap* heap = mLRUCache.head()->value();
         Serial lastSubmissionSerial = heap->GetLastSubmission();

         // If the next candidate for eviction was inserted into the LRU during the current serial,
         // it is because more memory is being used in a single command list than is available.
         // In this scenario, we cannot make any more resources resident and thrashing must occur.
         if (lastSubmissionSerial == mDevice->GetPendingCommandSerial()) {
             return nullptr;
         }

         // We must ensure that any previous use of a resource has completed before the resource can
         // be evicted.
         if (lastSubmissionSerial > mDevice->GetCompletedCommandSerial()) {
             DAWN_TRY(mDevice->WaitForSerial(lastSubmissionSerial));
         }

         heap->RemoveFromList();
         return heap;
     }

     // Any time we need to make something resident in local memory, we must check that we have
     // enough free memory to make the new object resident while also staying within our budget.
     // If there isn't enough memory, we should evict until there is.
     MaybeError ResidencyManager::EnsureCanMakeResident(uint64_t sizeToMakeResident) {
         if (!mResidencyManagementEnabled) {
             return {};
         }

         UpdateVideoMemoryInfo();

         uint64_t memoryUsageAfterMakeResident = sizeToMakeResident + mVideoMemoryInfo.dawnUsage;

         // Return when we can call MakeResident and remain under budget.
         if (memoryUsageAfterMakeResident < mVideoMemoryInfo.dawnBudget) {
             return {};
         }

         std::vector<ID3D12Pageable*> resourcesToEvict;
         uint64_t sizeNeededToBeUnderBudget =
             memoryUsageAfterMakeResident - mVideoMemoryInfo.dawnBudget;
         uint64_t sizeEvicted = 0;
         while (sizeEvicted < sizeNeededToBeUnderBudget) {
             Heap* heap;
             DAWN_TRY_ASSIGN(heap, RemoveSingleEntryFromLRU());

             // If no heap was returned, then nothing more can be evicted.
             if (heap == nullptr) {
                 break;
             }

             sizeEvicted += heap->GetSize();
             resourcesToEvict.push_back(heap->GetD3D12Pageable().Get());
         }

         if (resourcesToEvict.size() > 0) {
             DAWN_TRY(CheckHRESULT(
                 mDevice->GetD3D12Device()->Evict(resourcesToEvict.size(), resourcesToEvict.data()),
                 "Evicting resident heaps to free device local memory"));
         }

         return {};
     }

     // Ensure that we are only tracking heaps that exist in DXGI_MEMORY_SEGMENT_LOCAL.
     bool ResidencyManager::ShouldTrackHeap(Heap* heap) const {
         D3D12_HEAP_PROPERTIES heapProperties =
             mDevice->GetD3D12Device()->GetCustomHeapProperties(0, heap->GetD3D12HeapType());

         if (mDevice->GetDeviceInfo().isUMA) {
             // On UMA devices, MEMORY_POOL_L0 corresponds to MEMORY_SEGMENT_LOCAL, so we must track
             // heaps in MEMORY_POOL_L0. For UMA, all heaps types exist in MEMORY_POOL_L0.
             return heapProperties.MemoryPoolPreference == D3D12_MEMORY_POOL_L0;
         }

         // On non-UMA devices, MEMORY_POOL_L1 corresponds to MEMORY_SEGMENT_LOCAL, so only track the
         // heap if it is in MEMORY_POOL_L1. For non-UMA, DEFAULT heaps exist in MEMORY_POOL_L1,
         // while READBACK and UPLOAD heaps exist in MEMORY_POOL_L0.
         return heapProperties.MemoryPoolPreference == D3D12_MEMORY_POOL_L1;
     }

     // Given a list of heaps that are pending usage, this function will estimate memory needed,
     // evict resources until enough space is available, then make resident any heaps scheduled for
     // usage.
     MaybeError ResidencyManager::EnsureHeapsAreResident(Heap** heaps, size_t heapCount) {
         if (!mResidencyManagementEnabled) {
             return {};
         }

         std::vector<ID3D12Pageable*> heapsToMakeResident;
         uint64_t sizeToMakeResident = 0;

         Serial pendingCommandSerial = mDevice->GetPendingCommandSerial();
         for (size_t i = 0; i < heapCount; i++) {
             Heap* heap = heaps[i];

             // Depending on device architecture, the heap may not need tracked.
             if (!ShouldTrackHeap(heap)) {
                 continue;
             }

             // Heaps that are locked resident are not tracked in the LRU cache.
             if (heap->IsResidencyLocked()) {
                 continue;
             }

             if (heap->IsInResidencyLRUCache()) {
                 // If the heap is already in the LRU, we must remove it and append again below to
                 // update its position in the LRU.
                 heap->RemoveFromList();
             } else {
                 heapsToMakeResident.push_back(heap->GetD3D12Pageable().Get());
                 sizeToMakeResident += heap->GetSize();
             }

             // If we submit a command list to the GPU, we must ensure that heaps referenced by that
             // command list stay resident at least until that command list has finished execution.
             // Setting this serial unnecessarily can leave the LRU in a state where nothing is
             // eligible for eviction, even though some evictions may be possible.
             heap->SetLastSubmission(pendingCommandSerial);

             mLRUCache.Append(heap);
         }

         if (heapsToMakeResident.size() != 0) {
             DAWN_TRY(EnsureCanMakeResident(sizeToMakeResident));

             // Note that MakeResident is a synchronous function and can add a significant
             // overhead to command recording. In the future, it may be possible to decrease this
             // overhead by using MakeResident on a secondary thread, or by instead making use of
             // the EnqueueMakeResident function (which is not available on all Windows 10
             // platforms).
             DAWN_TRY(CheckHRESULT(mDevice->GetD3D12Device()->MakeResident(
                                       heapsToMakeResident.size(), heapsToMakeResident.data()),
                                   "Making scheduled-to-be-used resources resident in "
                                   "device local memory"));
         }

         return {};
     }

     // When a new heap is allocated, the heap will be made resident upon creation. We must track
     // when this happens to avoid calling MakeResident a second time.
     void ResidencyManager::TrackResidentAllocation(Heap* heap) {
         if (!mResidencyManagementEnabled) {
             return;
         }

         // Depending on device architecture and heap type, the heap may not need tracked.
         if (!ShouldTrackHeap(heap)) {
             return;
         }

         mLRUCache.Append(heap);
     }

     // Places an artifical cap on Dawn's budget so we can test in a predictable manner. If used,
     // this function must be called before any resources have been created.
     void ResidencyManager::RestrictBudgetForTesting(uint64_t artificialBudgetCap) {
         ASSERT(mLRUCache.empty());
         ASSERT(!mRestrictBudgetForTesting);

         mRestrictBudgetForTesting = true;
         UpdateVideoMemoryInfo();

         // Dawn has a non-zero memory usage even before any resources have been created, and this
         // value can vary depending on the environment Dawn is running in. By adding this in
         // addition to the artificial budget cap, we can create a predictable and reproducible
         // budget for testing.
         mVideoMemoryInfo.dawnBudget = mVideoMemoryInfo.dawnUsage + artificialBudgetCap;
     }

 }}  // namespace dawn_native::d3d12
	// Copyright 2020 The Dawn Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#include "dawn_native/d3d12/ResidencyManagerD3D12.h"

	#include "dawn_native/d3d12/AdapterD3D12.h"
	#include "dawn_native/d3d12/D3D12Error.h"
	#include "dawn_native/d3d12/DeviceD3D12.h"
	#include "dawn_native/d3d12/Forward.h"
	#include "dawn_native/d3d12/HeapD3D12.h"

	#include "dawn_native/d3d12/d3d12_platform.h"

	namespace dawn_native { namespace d3d12 {

	ResidencyManager::ResidencyManager(Device* device)
	: mDevice(device),
	mResidencyManagementEnabled(
	device->IsToggleEnabled(Toggle::UseD3D12ResidencyManagement)) {
	UpdateVideoMemoryInfo();
	}

	// Increments number of locks on a heap to ensure the heap remains resident.
	MaybeError ResidencyManager::LockHeap(Heap* heap) {
	if (!mResidencyManagementEnabled) {
	return {};
	}

	// Depending on device architecture, the heap may not need tracked.
	if (!ShouldTrackHeap(heap)) {
	return {};
	}

	// If the heap isn't already resident, make it resident.
	if (!heap->IsInResidencyLRUCache() && !heap->IsResidencyLocked()) {
	DAWN_TRY(EnsureCanMakeResident(heap->GetSize()));
	ID3D12Pageable* pageable = heap->GetD3D12Pageable().Get();
	DAWN_TRY(CheckHRESULT(mDevice->GetD3D12Device()->MakeResident(1, &pageable),
	"Making a scheduled-to-be-used resource resident in "
	"device local memory"));
	}

	// Since we can't evict the heap, it's unnecessary to track the heap in the LRU Cache.
	if (heap->IsInResidencyLRUCache()) {
	heap->RemoveFromList();
	}

	heap->IncrementResidencyLock();

	return {};
	}

	// Decrements number of locks on a heap. When the number of locks becomes zero, the heap is
	// inserted into the LRU cache and becomes eligible for eviction.
	void ResidencyManager::UnlockHeap(Heap* heap) {
	if (!mResidencyManagementEnabled) {
	return;
	}

	// Depending on device architecture, the heap may not need tracked.
	if (!ShouldTrackHeap(heap)) {
	return;
	}

	ASSERT(heap->IsResidencyLocked());
	ASSERT(!heap->IsInResidencyLRUCache());
	heap->DecrementResidencyLock();

	// When all locks have been removed, the resource remains resident and becomes tracked in
	// the LRU.
	if (!heap->IsResidencyLocked()) {
	mLRUCache.Append(heap);
	}
	}

	// Allows an application component external to Dawn to cap Dawn's residency budget to prevent
	// competition for device local memory. Returns the amount of memory reserved, which may be less
	// that the requested reservation when under pressure.
	uint64_t ResidencyManager::SetExternalMemoryReservation(uint64_t requestedReservationSize) {
	mVideoMemoryInfo.externalRequest = requestedReservationSize;
	UpdateVideoMemoryInfo();
	return mVideoMemoryInfo.externalReservation;
	}

	void ResidencyManager::UpdateVideoMemoryInfo() {
	if (!mResidencyManagementEnabled) {
	return;
	}

	DXGI_QUERY_VIDEO_MEMORY_INFO queryVideoMemoryInfo;
	ToBackend(mDevice->GetAdapter())
	->GetHardwareAdapter()
	->QueryVideoMemoryInfo(0, DXGI_MEMORY_SEGMENT_GROUP_LOCAL, &queryVideoMemoryInfo);

	// The video memory budget provided by QueryVideoMemoryInfo is defined by the operating
	// system, and may be lower than expected in certain scenarios. Under memory pressure, we
	// cap the external reservation to half the available budget, which prevents the external
	// component from consuming a disproportionate share of memory and ensures that Dawn can
	// continue to make forward progress. Note the choice to halve memory is arbitrarily chosen
	// and subject to future experimentation.
	mVideoMemoryInfo.externalReservation =
	std::min(queryVideoMemoryInfo.Budget / 2, mVideoMemoryInfo.externalRequest);

	mVideoMemoryInfo.dawnUsage =
	queryVideoMemoryInfo.CurrentUsage - mVideoMemoryInfo.externalReservation;

	// If we're restricting the budget for testing, leave the budget as is.
	if (mRestrictBudgetForTesting) {
	return;
	}

	// We cap Dawn's budget to 95% of the provided budget. Leaving some budget unused
	// decreases fluctuations in the operating-system-defined budget, which improves stability
	// for both Dawn and other applications on the system. Note the value of 95% is arbitrarily
	// chosen and subject to future experimentation.
	static constexpr float kBudgetCap = 0.95;
	mVideoMemoryInfo.dawnBudget =
	(queryVideoMemoryInfo.Budget - mVideoMemoryInfo.externalReservation) * kBudgetCap;
	}

	// Removes from the LRU and returns the least recently used heap when possible. Returns nullptr
	// when nothing further can be evicted.
	ResultOrError<Heap*> ResidencyManager::RemoveSingleEntryFromLRU() {
	ASSERT(!mLRUCache.empty());
	Heap* heap = mLRUCache.head()->value();
	Serial lastSubmissionSerial = heap->GetLastSubmission();

	// If the next candidate for eviction was inserted into the LRU during the current serial,
	// it is because more memory is being used in a single command list than is available.
	// In this scenario, we cannot make any more resources resident and thrashing must occur.
	if (lastSubmissionSerial == mDevice->GetPendingCommandSerial()) {
	return nullptr;
	}

	// We must ensure that any previous use of a resource has completed before the resource can
	// be evicted.
	if (lastSubmissionSerial > mDevice->GetCompletedCommandSerial()) {
	DAWN_TRY(mDevice->WaitForSerial(lastSubmissionSerial));
	}

	heap->RemoveFromList();
	return heap;
	}

	// Any time we need to make something resident in local memory, we must check that we have
	// enough free memory to make the new object resident while also staying within our budget.
	// If there isn't enough memory, we should evict until there is.
	MaybeError ResidencyManager::EnsureCanMakeResident(uint64_t sizeToMakeResident) {
	if (!mResidencyManagementEnabled) {
	return {};
	}

	UpdateVideoMemoryInfo();

	uint64_t memoryUsageAfterMakeResident = sizeToMakeResident + mVideoMemoryInfo.dawnUsage;

	// Return when we can call MakeResident and remain under budget.
	if (memoryUsageAfterMakeResident < mVideoMemoryInfo.dawnBudget) {
	return {};
	}

	std::vector<ID3D12Pageable*> resourcesToEvict;
	uint64_t sizeNeededToBeUnderBudget =
	memoryUsageAfterMakeResident - mVideoMemoryInfo.dawnBudget;
	uint64_t sizeEvicted = 0;
	while (sizeEvicted < sizeNeededToBeUnderBudget) {
	Heap* heap;
	DAWN_TRY_ASSIGN(heap, RemoveSingleEntryFromLRU());

	// If no heap was returned, then nothing more can be evicted.
	if (heap == nullptr) {
	break;
	}

	sizeEvicted += heap->GetSize();
	resourcesToEvict.push_back(heap->GetD3D12Pageable().Get());
	}

	if (resourcesToEvict.size() > 0) {
	DAWN_TRY(CheckHRESULT(
	mDevice->GetD3D12Device()->Evict(resourcesToEvict.size(), resourcesToEvict.data()),
	"Evicting resident heaps to free device local memory"));
	}

	return {};
	}

	// Ensure that we are only tracking heaps that exist in DXGI_MEMORY_SEGMENT_LOCAL.
	bool ResidencyManager::ShouldTrackHeap(Heap* heap) const {
	D3D12_HEAP_PROPERTIES heapProperties =
	mDevice->GetD3D12Device()->GetCustomHeapProperties(0, heap->GetD3D12HeapType());

	if (mDevice->GetDeviceInfo().isUMA) {
	// On UMA devices, MEMORY_POOL_L0 corresponds to MEMORY_SEGMENT_LOCAL, so we must track
	// heaps in MEMORY_POOL_L0. For UMA, all heaps types exist in MEMORY_POOL_L0.
	return heapProperties.MemoryPoolPreference == D3D12_MEMORY_POOL_L0;
	}

	// On non-UMA devices, MEMORY_POOL_L1 corresponds to MEMORY_SEGMENT_LOCAL, so only track the
	// heap if it is in MEMORY_POOL_L1. For non-UMA, DEFAULT heaps exist in MEMORY_POOL_L1,
	// while READBACK and UPLOAD heaps exist in MEMORY_POOL_L0.
	return heapProperties.MemoryPoolPreference == D3D12_MEMORY_POOL_L1;
	}

	// Given a list of heaps that are pending usage, this function will estimate memory needed,
	// evict resources until enough space is available, then make resident any heaps scheduled for
	// usage.
	MaybeError ResidencyManager::EnsureHeapsAreResident(Heap** heaps, size_t heapCount) {
	if (!mResidencyManagementEnabled) {
	return {};
	}

	std::vector<ID3D12Pageable*> heapsToMakeResident;
	uint64_t sizeToMakeResident = 0;

	Serial pendingCommandSerial = mDevice->GetPendingCommandSerial();
	for (size_t i = 0; i < heapCount; i++) {
	Heap* heap = heaps[i];

	// Depending on device architecture, the heap may not need tracked.
	if (!ShouldTrackHeap(heap)) {
	continue;
	}

	// Heaps that are locked resident are not tracked in the LRU cache.
	if (heap->IsResidencyLocked()) {
	continue;
	}

	if (heap->IsInResidencyLRUCache()) {
	// If the heap is already in the LRU, we must remove it and append again below to
	// update its position in the LRU.
	heap->RemoveFromList();
	} else {
	heapsToMakeResident.push_back(heap->GetD3D12Pageable().Get());
	sizeToMakeResident += heap->GetSize();
	}

	// If we submit a command list to the GPU, we must ensure that heaps referenced by that
	// command list stay resident at least until that command list has finished execution.
	// Setting this serial unnecessarily can leave the LRU in a state where nothing is
	// eligible for eviction, even though some evictions may be possible.
	heap->SetLastSubmission(pendingCommandSerial);

	mLRUCache.Append(heap);
	}

	if (heapsToMakeResident.size() != 0) {
	DAWN_TRY(EnsureCanMakeResident(sizeToMakeResident));

	// Note that MakeResident is a synchronous function and can add a significant
	// overhead to command recording. In the future, it may be possible to decrease this
	// overhead by using MakeResident on a secondary thread, or by instead making use of
	// the EnqueueMakeResident function (which is not available on all Windows 10
	// platforms).
	DAWN_TRY(CheckHRESULT(mDevice->GetD3D12Device()->MakeResident(
	heapsToMakeResident.size(), heapsToMakeResident.data()),
	"Making scheduled-to-be-used resources resident in "
	"device local memory"));
	}

	return {};
	}

	// When a new heap is allocated, the heap will be made resident upon creation. We must track
	// when this happens to avoid calling MakeResident a second time.
	void ResidencyManager::TrackResidentAllocation(Heap* heap) {
	if (!mResidencyManagementEnabled) {
	return;
	}

	// Depending on device architecture and heap type, the heap may not need tracked.
	if (!ShouldTrackHeap(heap)) {
	return;
	}

	mLRUCache.Append(heap);
	}

	// Places an artifical cap on Dawn's budget so we can test in a predictable manner. If used,
	// this function must be called before any resources have been created.
	void ResidencyManager::RestrictBudgetForTesting(uint64_t artificialBudgetCap) {
	ASSERT(mLRUCache.empty());
	ASSERT(!mRestrictBudgetForTesting);

	mRestrictBudgetForTesting = true;
	UpdateVideoMemoryInfo();

	// Dawn has a non-zero memory usage even before any resources have been created, and this
	// value can vary depending on the environment Dawn is running in. By adding this in
	// addition to the artificial budget cap, we can create a predictable and reproducible
	// budget for testing.
	mVideoMemoryInfo.dawnBudget = mVideoMemoryInfo.dawnUsage + artificialBudgetCap;
	}

	}} // namespace dawn_native::d3d12