[Question] Support head_dim=256 for attention ops (Qwen3.5/3.6-style GDN-hybrid models) ?

Open
#70 0 comments 3 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
48/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Quiet
Tech stack
cpp

Research direction

Start by locating the attention operator implementation and the existing head_dim=80/128 handling. Trace how attention configurations are validated, then check whether a head_dim=256 configuration can run for the cited Qwen3.5/3.6-style full-attention layers. Done means the new configuration is supported and its end-to-end latency impact is benchmarked.

Written by the indexing model from the issue text.

Description

  • The attention ops currently support only head_dim = 80 / 128.Could head_dim=256 be added?

  • Recent GDN-hybrid models (Qwen3.5 / 3.6) use head_dim=256 in their full-attention layers, so this would unblock those configs.

  • One question: since GDN (linear-attention) layers dominate these models,how much end-to-end latency benefit can we realistically expect from optimizing the full-attention op here? Has anyone benchmarked hpc_ops attention on a Qwen3.5/3.6-class model?

  • Happy to help test if a branch is available.

Dominant language
C++
Stars
1.2k
Forks
142
Avg merge
23h 15m
Merged PRs (30d)
8

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from Tencent/hpc-ops

All issues in Tencent/hpc-ops

Similar issues

More C++ issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.