[GH-ISSUE #50] "it employs CUDA-core two-level accumulation (promotion)" #32

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opened 2026-10-26 21:10:55 +00:00 by bsakaguchi · 1 comment
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Originally created by @cxw-droid on GitHub (Mar 7, 2025).
Original GitHub issue: https://github.com/deepseek-ai/DeepGEMM/issues/50

May I know what is the meaning of the two-level here? Does it mean FP8->BF16->FP32? Thanks.

Originally created by @cxw-droid on GitHub (Mar 7, 2025). Original GitHub issue: https://github.com/deepseek-ai/DeepGEMM/issues/50 May I know what is the meaning of the `two-level` here? Does it mean FP8->BF16->FP32? Thanks.
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@soundOfDestiny commented on GitHub (Mar 8, 2025):

In the current Tensor Core
implementation of the NVIDIA Hopper architecture, FP8 GEMM (General Matrix Multiply)
employs fixed-point accumulation, aligning the mantissa products by right-shifting based on
the maximum exponent before addition. Our experiments reveal that it only uses the highest 14 bits of each mantissa product after sign-fill right shifting, and truncates bits exceeding this range.

FP8 GEMM -> FP22 result per 128 along K dimension -> FP32 accumulation

<!-- gh-comment-id:2707877416 --> @soundOfDestiny commented on GitHub (Mar 8, 2025): In the current Tensor Core implementation of the NVIDIA Hopper architecture, FP8 GEMM (General Matrix Multiply) employs fixed-point accumulation, aligning the mantissa products by right-shifting based on the maximum exponent before addition. Our experiments reveal that it only uses the highest 14 bits of each mantissa product after sign-fill right shifting, and truncates bits exceeding this range. FP8 GEMM -> FP22 result per 128 along K dimension -> FP32 accumulation
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deepseek-ai/DeepGEMM#32
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