Single Batch Overlap (SBO): Overlaping of Down GEMM with Combine Send #483
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Co-authored-by: Sulfur6 <[email protected]> Co-authored-by: AniZpZ <[email protected]>
wangfakang
reviewed
Nov 6, 2025
Co-authored-by: sky <[email protected]>
Co-authored-by: sky <[email protected]>
qhsc
reviewed
Nov 18, 2025
| for (int token_idx = offset + sub_warp_id; token_idx < offset + num_tokens_to_send; token_idx += num_warps_per_group) { | ||
| if (overlap or (not is_rank_masked<true>(mask_buffer_ptr, dst_rank))) { | ||
| auto token_start_idx = overlap ? local_expert_signal_idx * block_m : offset; | ||
| auto token_end_idx = overlap ? min((local_expert_signal_idx + 1) * block_m, num_tokens_per_expert) : (offset + num_tokens_to_send); |
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Hi~ I have tried this great feature, and foud that combine_send was slower than the non-overlap situation, maybe block_m is too big for one SM in each itertions? I
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You may consider increasing num_sms from the default value of 3 to 4-6. When block_m is set to 64, given that num_warps is 32: if num_token <= 32, one SM sends a single round; if 32 < num_token <= 64, one SM needs to send two rounds. Two rounds may take slightly longer than the origin combined send, but you can increase parallelism by raising num_sms.
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The DeepEP implementation for SBO (DeepEP #390) will be merged into the antgroup-opt branch.