Fix XNNWorkspaceManager cleanup tests by using unique IDs instead of raw pointers

[mergennachin]

Summary:
The PerModelModeCleanup and GlobalModeCleanup tests were failing because they
compared raw xnn_workspace_t pointers to verify cleanup behavior. However,
memory allocators commonly reuse addresses after deallocation - when
xnn_release_workspace frees memory and xnn_create_workspace immediately
allocates the same size, the allocator may return the same address.

This fix:

1. Adds a unique instance ID (uint64_t) to XNNWorkspace using an atomic counter
2. Adds an id() method to retrieve this unique ID
3. Modifies both cleanup tests to compare IDs instead of raw pointers

This correctly verifies that new workspace objects are created after cleanup,
regardless of memory address reuse by the allocator.

Differential Revision: D90897333

[pytorch-bot]

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❌ 2 Cancelled Jobs, 6 Unrelated Failures

As of commit 9591f72 with merge base d305410 ():

CANCELLED JOBS - The following jobs were cancelled. Please retry:

• pull / test-static-llama-qnn-linux (stories_110m) / linux-job (gh)
  ##[error]The operation was canceled.
• pull / test-static-llama-qnn-linux (stories_260k_bc) / linux-job (gh)
  ##[error]The operation was canceled.

FLAKY - The following job failed but was likely due to flakiness present on trunk:

• pull / unittest / windows / windows-job (gh) (similar failure)
  backends/test/harness/tests/test_error_statistics.py::ErrorStatisticsTests::test_error_stats_simple

BROKEN TRUNK - The following jobs failed but was present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / linux / linux-job (gh) (trunk failure)
  backends/test/harness/tests/test_error_statistics.py::ErrorStatisticsTests::test_error_stats_simple
• pull / unittest / macos / macos-job (gh) (trunk failure)
  backends/test/harness/tests/test_error_statistics.py::ErrorStatisticsTests::test_error_stats_simple
• pull / unittest-editable / linux / linux-job (gh) (trunk failure)
  backends/test/harness/tests/test_error_statistics.py::ErrorStatisticsTests::test_error_stats_simple
• pull / unittest-editable / macos / macos-job (gh) (trunk failure)
  backends/test/harness/tests/test_error_statistics.py::ErrorStatisticsTests::test_error_stats_simple
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  backends/test/harness/tests/test_error_statistics.py::ErrorStatisticsTests::test_error_stats_simple

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[meta-codesync]

@mergennachin has exported this pull request. If you are a Meta employee, you can view the originating Diff in D90897333.

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[Copilot]

Pull request overview

This PR fixes failing workspace manager cleanup tests by introducing unique instance IDs to distinguish between workspace objects, solving the issue where memory allocators reuse addresses after deallocation.

Changes:

• Added a unique ID mechanism to XNNWorkspace using an atomic counter
• Modified cleanup tests to compare workspace IDs instead of raw pointers
• Added explanatory comments documenting why ID comparison is used

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
backends/xnnpack/runtime/XNNWorkspace.h	Added atomic counter for unique IDs, id() getter method, and id_ member variable to XNNWorkspace class
backends/xnnpack/test/runtime/test_workspace_manager.cpp	Updated PerModelModeCleanup and GlobalModeCleanup tests to compare workspace IDs instead of raw pointers

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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