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A high-throughput and memory-efficient inference and serving engine for LLMs

Mirrored from https://github.com/tduncan-lum/Nvidia-Optimization-Stack---VLLM.git

Synced Nov 12, 09:45 UTC

Guard FlashInfer sampler using the same check as FlashInfer attention backend (#29415)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com> Co-authored-by: Cyrus Leung <tlleungac@connect.ust.hk>

Harry Mellor committed Nov 28, 2025 at 16:34 UTC 9eec282cb5a6fe0b39449476dc4d14da0516984c
1 file changed +10
vllm/v1/sample/ops/topk_topp_sampler.py
+10
@@ -33,6 +33,16 @@ class TopKTopPSampler(nn.Module):
33 and current_platform.is_cuda()
34 ):
35 if envs.VLLM_USE_FLASHINFER_SAMPLER:
36 + from vllm.v1.attention.backends.flashinfer import FlashInferBackend
37 +
38 + capability = current_platform.get_device_capability()
39 + assert capability is not None
40 + if not FlashInferBackend.supports_compute_capability(capability):
41 + capability_str = capability.as_version_str()
42 + raise RuntimeError(
43 + "FlashInfer does not support compute capability "
44 + f"{capability_str}, unset VLLM_USE_FLASHINFER_SAMPLER=1."
45 + )
46 # Users must opt in explicitly via VLLM_USE_FLASHINFER_SAMPLER=1.
47 logger.info_once(
48 "Using FlashInfer for top-p & top-k sampling.",