Skip to content

Temporary disable persistent topk #41442

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ywang96 merged 1 commit into from
May 1, 2026
+1 −1
Merged

Temporary disable persistent topk #41442

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion vllm/model_executor/layers/sparse_attn_indexer.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -320,7 +320,7 @@ def sparse_attn_indexer(
num_rows = logits.shape[0]
topk_indices = topk_indices_buffer[:num_padded_tokens, :topk_tokens]

if current_platform.is_cuda() and topk_tokens in (512, 1024, 2048):
if current_platform.is_cuda() and topk_tokens in (512, 2048):
Copy link
Copy Markdown
Contributor

@gemini-code-assist gemini-code-assist Bot May 1, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

high

The PR title 'Temporary disable persistent topk' suggests an intent to disable the persistent topk optimization entirely. However, the current implementation only removes the 1024 case, leaving it enabled for 512 and 2048. If the kernel is being disabled due to a general issue (e.g., stability or correctness), it should likely be disabled for all supported sizes to ensure the workaround is effective across all configurations.

workspace_manager = current_workspace_manager()
(topk_workspace,) = workspace_manager.get_simultaneous(
((RADIX_TOPK_WORKSPACE_SIZE,), torch.uint8),
Expand Down
Loading