Disable prefetching by default.

include/gpgmm_d3d12.h

@@ -782,11 +782,12 @@ namespace gpgmm::d3d12 {
         */
         RESOURCE_ALLOCATOR_FLAG_ALWAYS_IN_BUDGET = 0x2,
 
-        /** \brief Disables pre-fetching of GPU memory.
+        /** \brief Allow pre-fetching of resource heaps on background thread.
 
-        Should be only used for debugging and testing purposes.
+        Allows GPGMM to trigger prefetching based on heurstics. Prefetching enables more
+        performance when allocating for contiguous allocations or many resources of the same size.
         */
-        RESOURCE_ALLOCATOR_FLAG_DISABLE_PREFETCH = 0x4,
+        RESOURCE_ALLOCATOR_FLAG_ALLOW_PREFETCH = 0x4,
 
         /** \brief Disables recycling of GPU memory.
 
@@ -1057,12 +1058,9 @@ namespace gpgmm::d3d12 {
         */
         ALLOCATION_FLAG_NEVER_SUBALLOCATE_HEAP = 0x4,
 
-        /** \brief Prefetch memory for the next resource allocation.
+        /** \brief Force pre-fetch for the next resource allocation.
 
-        The call to prefetch is deferred to a background thread by GPGMM which runs
-        when the current allocation requested is completed. By default, GPGMM will automatically
-        trigger prefetching based on heurstics. Prefetching enables more performance when
-        allocating for contiguous allocations or many resources of the same size.
+        This flag has no effect if RESOURCE_ALLOCATOR_FLAG_ALLOW_PREFETCH was not specified.
 
         Should not be used with ALLOCATION_FLAG_NEVER_ALLOCATE_HEAP.
         */

src/gpgmm/d3d12/ResourceAllocatorD3D12.cpp

@@ -772,7 +772,7 @@ namespace gpgmm::d3d12 {
                                   descriptor.ResourceHeapFragmentationLimit,
                                   descriptor.ResourceHeapGrowthFactor,
                                   /*allowSlabPrefetch*/
-                                  !(descriptor.Flags & RESOURCE_ALLOCATOR_FLAG_DISABLE_PREFETCH),
+                                  (descriptor.Flags & RESOURCE_ALLOCATOR_FLAG_ALLOW_PREFETCH),
                                   std::move(pooledOrNonPooledAllocator));
     }
 

src/tests/capture_replay_tests/D3D12MemoryTraceReplay.cpp

@@ -204,8 +204,8 @@ class D3D12MemoryTraceReplay : public D3D12TestBase, public CaptureReplayTestWit
             baseAllocatorDesc.RecordOptions.EventScope = RECORD_SCOPE_PER_INSTANCE;
         }
 
-        if (!envParams.IsPrefetchAllowed) {
-            baseAllocatorDesc.Flags |= RESOURCE_ALLOCATOR_FLAG_DISABLE_PREFETCH;
+        if (envParams.IsPrefetchAllowed) {
+            baseAllocatorDesc.Flags |= RESOURCE_ALLOCATOR_FLAG_ALLOW_PREFETCH;
         }
 
         RESIDENCY_MANAGER_DESC baseResidencyDesc = CreateBasicResidencyDesc();

src/tests/end2end/D3D12ResidencyManagerTests.cpp

@@ -42,8 +42,6 @@ class D3D12ResidencyManagerTests : public D3D12TestBase, public ::testing::Test
     RESOURCE_ALLOCATOR_DESC CreateBasicAllocatorDesc() const {
         RESOURCE_ALLOCATOR_DESC desc = D3D12TestBase::CreateBasicAllocatorDesc();
 
-        // Disable pre-fetching since it will could cause over-committment unpredictably.
-        desc.Flags |= gpgmm::d3d12::RESOURCE_ALLOCATOR_FLAG_DISABLE_PREFETCH;
 
         // Require MakeResident/Evict occur near CreateResource, for debugging purposes.
         desc.Flags |= gpgmm::d3d12::RESOURCE_ALLOCATOR_FLAG_ALWAYS_IN_BUDGET;

src/tests/end2end/D3D12ResourceAllocatorTests.cpp

@@ -65,10 +65,6 @@ class D3D12ResourceAllocatorTests : public D3D12TestBase, public ::testing::Test
     RESOURCE_ALLOCATOR_DESC CreateBasicAllocatorDesc() const {
         RESOURCE_ALLOCATOR_DESC desc = D3D12TestBase::CreateBasicAllocatorDesc();
 
-        // Pre-fetching is enabled by default. However for testing purposes, pre-fetching changes
-        // expectations that check GPU memory usage and needs to be tested in isolation.
-        desc.Flags |= RESOURCE_ALLOCATOR_FLAG_DISABLE_PREFETCH;
-
         // Make sure leak detection is always enabled.
         desc.Flags |= gpgmm::d3d12::RESOURCE_ALLOCATOR_FLAG_NEVER_LEAK;
 
@@ -1741,10 +1737,8 @@ TEST_F(D3D12ResourceAllocatorTests, CreateBufferManyPrefetch) {
     GPGMM_SKIP_TEST_IF(true);
 #endif
 
-    // Prefetching is explicitly disabled but otherwise allowed, re-enable it by clearing the
-    // disable flag.
     RESOURCE_ALLOCATOR_DESC allocatorDesc = CreateBasicAllocatorDesc();
-    allocatorDesc.Flags ^= RESOURCE_ALLOCATOR_FLAG_DISABLE_PREFETCH;
+    allocatorDesc.Flags |= RESOURCE_ALLOCATOR_FLAG_ALLOW_PREFETCH;
 
     ComPtr<IResourceAllocator> resourceAllocator;
     ASSERT_SUCCEEDED(CreateResourceAllocator(allocatorDesc, mDevice.Get(), mAdapter.Get(),