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In principle, the accuracy should be very similar. Please also check this PR for more details: sgl-project/sglang#16818
In our own tests, we did observe that on some prompts the generation results can differ slightly, even under greedy decoding. We believe this is caused by numerical randomness introduced by the attention kernel. That said, we do not observe a significant accuracy drop overall—speculative decoding is theoretically lossless, so it should not degrade performance in expectation.
Could you please share your test environment (hardware, CUDA / PyTorch versions) and the evaluation code or scripts you used? That would help us reproduce the issue and better understand the root cause.
Yes outputs diverge on some prompts due to kernel differences, this is a known thing for other speculative decoding models as well. This also happens depending on concurrency/batch size for non speculative decoding!
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jianc99 commentedon Jan 14, 2026
Thanks for reporting this.
In principle, the accuracy should be very similar. Please also check this PR for more details:
sgl-project/sglang#16818
In our own tests, we did observe that on some prompts the generation results can differ slightly, even under greedy decoding. We believe this is caused by numerical randomness introduced by the attention kernel. That said, we do not observe a significant accuracy drop overall—speculative decoding is theoretically lossless, so it should not degrade performance in expectation.
Could you please share your test environment (hardware, CUDA / PyTorch versions) and the evaluation code or scripts you used? That would help us reproduce the issue and better understand the root cause.
dcw02 commentedon Jan 14, 2026
Yes outputs diverge on some prompts due to kernel differences, this is a known thing for other speculative decoding models as well. This also happens depending on concurrency/batch size for non speculative decoding!
mZhenz commentedon Jan 15, 2026
感谢回复,
diff和transformers版本有关,对齐transformers==4.57.3后指标没有diff了,使用transformers==5.0.0会有比较大的diff。
HW ideas feasibility loop: 7 studies, 1 shippable win