Add XAML profiler memory attribution

[Akanksha Patel (akanpatel2206)]

Summary

• add outstanding XAML allocator accounting and heap snapshots
• trace DComp surface lifecycle, backing textures, visual associations, and process GPU memory
• preserve the current public allocator behavior and the 10-field ElementEnteredTree payload

Validation

• amd64chk Microsoft.UI.Xaml project build: 0 warnings, 0 errors
• amd64fre Microsoft.UI.Xaml project build with local PGO disabled: 0 warnings, 0 errors
• WinUI code review: no Critical, Important, or Minor findings

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[Copilot]

Pull request overview

Adds XAML profiler tracing to attribute CPU heap usage and DComp/GPU surface usage to specific XAML surfaces/visuals, enabling heap and GPU memory snapshots alongside existing tree/visual tracing.

Changes:

• Introduces new XamlProfilerTracing events for XAML heap snapshots, DComp surface lifecycle/texture observations, visual→surface associations, and GPU memory snapshots.
• Adds instrumentation in DCompSurface and VisualContentRenderer to emit these events during surface creation/resize/release and primitive rendering.
• Extends XcpAllocation with outstanding-allocation accounting and heap metadata used by the new heap snapshot event.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
dxaml/xcp/plat/win/desktop/DCompSurface.h	Declares profiler-only helpers for surface memory/texture observation tracing.
dxaml/xcp/plat/win/desktop/DCompSurface.cpp	Emits DComp surface lifecycle/texture observations + heap/GPU snapshots when profiler is enabled.
dxaml/xcp/core/hw/VisualContentRenderer.cpp	Traces visual-to-surface associations for brush/mask roles when profiler is enabled.
dxaml/xcp/core/core/elements/uielement.cpp	Emits XAML heap snapshots alongside existing Enter/Leave profiler events.
dxaml/xcp/components/base/inc/XamlProfilerTracing.h	Defines new TraceLogging events for heap, DComp surface, visual surface, and GPU snapshots.
dxaml/xcp/components/allocation/lib/XcpAllocation.cpp	Adds outstanding allocation tracking and heap metadata accessors used by heap snapshot tracing.
dxaml/xcp/components/allocation/inc/XcpAllocation.h	Declares new allocation statistics/heap metadata APIs.

Suppressed comments (1)

dxaml/xcp/plat/win/desktop/DCompSurface.cpp:1132

• Resize() traces a profiler "deallocation" (TraceProfilerMemoryChange(false)) before calling m_compositionSurfaceHelper.Resize(...). If Resize fails, the trace stream will contain an unmatched deallocation for a surface that is still alive (and the corresponding allocation trace is skipped).

    ASSERT(m_compositionSurfaceHelper.HasSurface());

#ifdef XAMLPROFILER_ENABLED
    TraceProfilerMemoryChange(false);
#endif

    if (!IsVirtual())
    {
        UpdateMemoryFootprint(FALSE);
    }

    IFC(m_compositionSurfaceHelper.Resize(width, height));

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated no new comments.

Suppressed comments (1)

dxaml/xcp/components/allocation/lib/XcpAllocation.cpp:320

• OSMemoryResize updates g_outstandingAllocSize on successful HeapReAlloc, but it never increments g_outstandingAllocCount when pAddress == nullptr (realloc used as initial allocation, which the _Frees_ptr_opt_ contract allows). This will undercount outstanding allocations in XamlHeapSnapshot for any allocations that go through the realloc callback path (e.g. LineServices).

    if (newAddress)
    {
        const size_t cNewSize = XcpAllocation::OSMemoryGetBlockSize(newAddress);
        if (cNewSize >= cOldSize)
        {

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Suppressed comments (3)

Previously missed (3) — in code that hasn't changed since the last review.

dxaml/xcp/core/hw/VisualContentRenderer.cpp:435

• The profiler VisualSurfaceChanged events are emitted before LinkVisual(). If LinkVisual fails (e.g., InsertVisualIntoCurrentContainer/Collection failure), the trace will record a visual/surface association that never actually became part of the composition tree, which can desync profiler state.

    IFC_RETURN(LinkVisual(brush, nullptr, spVisual.Get()));

dxaml/xcp/plat/win/desktop/DCompSurface.cpp:1382

• TraceProfilerTextureObserved dereferences updateObject unconditionally. Even though current call sites likely pass a non-null COM pointer on success, a defensive null check would avoid a crash in profiler-enabled builds if a future caller passes nullptr or if a BeginDraw implementation ever returns S_OK with a null surface.

    if (FAILED(updateObject->QueryInterface(IID_PPV_ARGS(&texture))))

dxaml/xcp/components/allocation/lib/XcpAllocation.cpp:365

• OSMemoryFree caches g_memoryTrackingEnabled into trackMemory, but then re-reads the global flag inside the block. Using the cached value keeps the function internally consistent (and avoids relying on a second non-atomic read).

        if (g_memoryTrackingEnabled)
        {
            UpdateAllocatedMemory(-(INT64)cSize);
        }

[Akanksha Patel (akanpatel2206)]

/azp

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[Godly T.Alias (godlytalias)]

The increment in RecordOutstandingAllocation and this decrement are both guarded on the size being non-zero, but OSMemoryResize can change that in between and never adjusts g_outstandingAllocCount. A block resized down to 0 then never gets decremented here, and one grown from 0 was never incremented so this fetch_sub wraps. UpdateAllocatedMemory already clamps for the same reason — we may have to do the same here.

[Godly T.Alias (godlytalias)]

This is emitted after the failure exits above, but m_pCompositionSurface / m_pVirtualCompositionSurface can already be set by then — so if we return early there, ReleaseLegacyDCompResources still sees them non-null and emits the matching false on its own. The other InitializeSurface overload emits before its failure exits, which avoids this — same as what we corrected in Resize. May be we can move it up to match.

[Akanksha Patel (akanpatel2206)]

/azp

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[Akanksha Patel (akanpatel2206)]

/azp run

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