test_onednn_attention_gqa_vs_math_float16_batch_size_2_n_head_64_n_head_kv_16_q_size_9216_kv_size_77_head_dim_64_is_causal_False_xpu_float16 - AssertionError: Tensor-likes are not close!

[mazurjax]

🐛 Describe the bug

1 UT fails on Windows LNL with "AssertionError: Tensor-likes are not close!"

Version	Status
pytorch_2.15_nightly_20260915	Passed
pytorch_2.15_nightly_20260916	Failed

Affected Test Cases

test_transformers_xpu.py::TestSDPAXpuOnlyXPU::test_onednn_attention_gqa_vs_math_float16_batch_size_2_n_head_64_n_head_kv_16_q_size_9216_kv_size_77_head_dim_64_is_causal_False_xpu_float16

Error log

_ TestSDPAXpuOnlyXPU.test_onednn_attention_gqa_vs_math_float16_batch_size_2_n_head_64_n_head_kv_16_q_size_9216_kv_size_77_head_dim_64_is_causal_False_xpu_float16 _
[gw0] win32 -- Python 3.12.14 C:\Users\gta\miniforge3\envs\pytorch_2.15_nightly_20260916\python.exe
Traceback (most recent call last):
  File "C:\Users\gta\repositories\pytorch\pytorch\third_party\torch-xpu-ops\test\xpu\test_transformers_xpu.py", line 6739, in test_onednn_attention_gqa_vs_math
    self.assertEqual(
  File "C:\Users\gta\miniforge3\envs\pytorch_2.15_nightly_20260916\Lib\site-packages\torch\testing\_internal\common_utils.py", line 4964, in assertEqual
    raise error_metas.pop()[0].to_error(  # type: ignore[index]
AssertionError: Tensor-likes are not close!

Mismatched elements: 1024 / 75497472 (0.0%)
Greatest absolute difference: nan at index (0, 8, 240, 0) (up to 0.01 allowed)
Greatest relative difference: nan at index (0, 8, 240, 0) (up to 0.01 allowed)

Versions

Click to expand traceback

PyTorch version: 2.15.0.dev20260916+xpu Is debug build: False CUDA used to build PyTorch: None ROCm SDK used to build PyTorch: N/A HIP used to build PyTorch: N/A

OS: Microsoft Windows 11 Pro (10.0.26200 64-bit)
GCC version: Could not collect
Clang version: Could not collect
CMake version: version 3.31.6
Libc version: N/A

Python version: 3.12.14 | packaged by conda-forge | (main, Sep 2 2026, 23:18:20) [MSC v.1944 64 bit (AMD64)] (64-bit runtime)
Python platform: Windows-11-10.0.26200-SP0
Is CUDA available: False
CUDA runtime version: No CUDA
CUDA_MODULE_LOADING set to: N/A
GPU models and configuration: No CUDA
Nvidia driver version: No CUDA
cuDNN version: No CUDA
Is XPU available: True
XPU used to build PyTorch: 20260100
Intel GPU driver version:

• 32.0.101.8993 (20260910000000.***+)
  Intel GPU models onboard:
• Intel(R) Arc(TM) 140V GPU (16GB)
  Intel GPU models detected:
• [0] _XpuDeviceProperties(name='Intel(R) Arc(TM) 140V GPU (16GB)', platform_name='Intel(R) oneAPI Unified Runtime over Level-Zero V2', type='gpu', device_id=0x64A0, uuid=8680a064-0400-0000-0002-000000000000, driver_version='1.15.39183+4', total_memory=16870MB, local_mem_size=128KB, last_level_cache_size=8192KB, max_compute_units=64, memory_clock_rate=0MHz, memory_bus_width=64-bit, gpu_eu_count=64, gpu_subslice_count=8, max_work_group_size=1024, max_num_sub_groups=64, sub_group_sizes=[16 32], has_fp16=1, has_fp64=1, has_atomic64=1, is_integrated_gpu=1)
  HIP runtime version: N/A
  MIOpen runtime version: N/A
  Is XNNPACK available: False
  Caching allocator config: N/A

CPU:
Name: Intel(R) Core(TM) Ultra 7 258V
Manufacturer: GenuineIntel
Family: 774
Architecture: 9
ProcessorType: 3
DeviceID: CPU0
CurrentClockSpeed: 2200
MaxClockSpeed: 2200
L2CacheSize: 14336
L2CacheSpeed: None
Revision: None

Versions of relevant libraries:
[pip3] dpcpp-cpp-rt==2026.1.0
[pip3] intel-cmplr-lib-rt==2026.1.0
[pip3] intel-cmplr-lib-ur==2026.1.0
[pip3] intel-cmplr-lic-rt==2026.1.0
[pip3] intel-opencl-rt==2026.1.0
[pip3] intel-openmp==2026.1.0
[pip3] intel-pti==1.0.1
[pip3] intel-sycl-rt==2026.1.0
[pip3] mkl==2026.1.0
[pip3] mkl-include==2024.2.0
[pip3] mkl-static==2024.2.0
[pip3] mypy_extensions==1.1.0
[pip3] numpy==1.26.4
[pip3] onemkl-license==2026.1.0
[pip3] onemkl-sycl-blas==2026.1.0
[pip3] onemkl-sycl-dft==2026.1.0
[pip3] onemkl-sycl-lapack==2026.1.0
[pip3] onemkl-sycl-rng==2026.1.0
[pip3] onemkl-sycl-sparse==2026.1.0
[pip3] onnx==1.21.0
[pip3] onnx-ir==0.1.16
[pip3] onnxscript==0.6.2
[pip3] optree==0.13.0
[pip3] tbb==2023.1.0
[pip3] tbb-devel==2021.13.1
[pip3] tcmlib==1.5.0
[pip3] torch==2.15.0.dev20260916+xpu
[pip3] torchaudio==2.11.0.dev20260916+xpu
[pip3] torchvision==0.30.0.dev20260916+xpu
[pip3] triton-xpu==3.8.0+git1e2d42a0
[pip3] umf==1.1.0
[conda] dpcpp-cpp-rt 2026.1.0 pypi_0 pypi
[conda] intel-cmplr-lib-rt 2026.1.0 pypi_0 pypi
[conda] intel-cmplr-lib-ur 2026.1.0 pypi_0 pypi
[conda] intel-cmplr-lic-rt 2026.1.0 pypi_0 pypi
[conda] intel-opencl-rt 2026.1.0 pypi_0 pypi
[conda] intel-openmp 2026.1.0 pypi_0 pypi
[conda] intel-pti 1.0.1 pypi_0 pypi
[conda] intel-sycl-rt 2026.1.0 pypi_0 pypi
[conda] mkl 2026.1.0 pypi_0 pypi
[conda] mkl-include 2024.2.0 pypi_0 pypi
[conda] mkl-static 2024.2.0 pypi_0 pypi
[conda] numpy 1.26.4 pypi_0 pypi
[conda] onemkl-license 2026.1.0 pypi_0 pypi
[conda] onemkl-sycl-blas 2026.1.0 pypi_0 pypi
[conda] onemkl-sycl-dft 2026.1.0 pypi_0 pypi
[conda] onemkl-sycl-lapack 2026.1.0 pypi_0 pypi
[conda] onemkl-sycl-rng 2026.1.0 pypi_0 pypi
[conda] onemkl-sycl-sparse 2026.1.0 pypi_0 pypi
[conda] optree 0.13.0 pypi_0 pypi
[conda] tbb 2023.1.0 pypi_0 pypi
[conda] tbb-devel 2021.13.1 pypi_0 pypi
[conda] tcmlib 1.5.0 pypi_0 pypi
[conda] torch 2.15.0.dev20260916+xpu pypi_0 pypi
[conda] torchaudio 2.11.0.dev20260916+xpu pypi_0 pypi
[conda] torchvision 0.30.0.dev20260916+xpu pypi_0 pypi
[conda] triton-xpu 3.8.0+git1e2d42a0 pypi_0 pypi
[conda] umf 1.1.0 pypi_0 pypi