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Enable multiple of 16 padding for INT8 Tensor Cores - #1982

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jordimas merged 2 commits into
OpenNMT:masterfrom
Purfview:patch-5
Jan 21, 2026
Merged

jordimas merged 2 commits into
OpenNMT:masterfrom
Purfview:patch-5

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@Purfview

@Purfview Purfview commented Jan 18, 2026 •

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Enable multiple of 16 padding for INT8 Tensor Cores.
Re-enable INT8 for sm120 - Blackwell GPUs ( revert #1937 )
Thanks @sssshhhhhh for the hint. πŸ‘

Closes: #1981 #1865

INT8 padding was disabled in #332 for reason it appears padding to a multiple of 16 does not help.
I guess, "does not help" meant that padding didn't increase performance.

Tests:
Tested older GPU (Turing) with INT8 Tensor Cores: vocab (n[fw]) is padded, no change in performance (as I remember, ~4% of GEMM calls needed padding).
I don't have Blackwell GPU at hand to test, but the padding should fix "CUBLAS_STATUS_NOT_SUPPORTED" error.

@Purfview

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Confirmed that it works on RTX 5060 Ti: #1981 (comment)

@easyfab

easyfab commented Jan 21, 2026

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Does the new CUDA Release 13.1 Update 1 fix this problem or is it another issue ?

from release notes :

Fixed an issue where cublasLtMatmul with FP8 arguments and CUBLASLT_MATMUL_MATRIX_SCALE_SCALAR_32F scaling mode (default) incorrectly required scaling factor addresses to be 16-byte aligned. This issue existed since cuBLAS 12.9. [5728938]

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@easyfab This is another issue.

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INT8 not allowed on RTX 5060 Ti

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