[MLAS] Enable BF16 KAI SBGemm on NCHWc ARM builds#27703
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hariharans29 merged 2 commits intomainfrom Mar 18, 2026
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Pull request overview
Enables KleidiAI (KAI) BF16 SBGEMM support on ARM64 builds even when NCHWc is enabled, while explicitly preventing the KAI SBGEMM override from being used by the NCHWc BF16 pointwise convolution kernel (keeping Conv on the default MLAS path).
Changes:
- Remove the
!defined(MLAS_USE_ARM_NEON_NCHWC)gating so KAI SBGEMM overrides can be built/used on NCHWc ARM64 builds. - Force-disable KleidiAI selection for the NCHWc BF16 pointwise conv kernel to avoid using the KAI SBGEMM path there.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
onnxruntime/core/mlas/lib/sbgemm.h |
Enables KAI override hooks for SBGEMM APIs regardless of NCHWc being enabled. |
onnxruntime/core/mlas/lib/sbconv_kernel_neon.cpp |
Forces use_kleidiai=false for the BF16 pointwise NCHWc conv call site to keep it on the default MLAS SBGEMM path. |
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edgchen1
approved these changes
Mar 18, 2026
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Description
Allow using KAI SBGemm on any ARM64 build (previously it needed the condition that NCHWc be not enabled as the logistics of using the KAI SBGemm path for the SBGemm based Conv was not clear). This change instead allows using the KAI path for other call sites (by enabling it in the build) but explicitly disallows using the KAI path only for the Conv and continue using the default MLAS path for the same (as before).
Motivation and Context
#26773 (comment)