Skip to content

trtllm mHC: collect fused_hc on SM100/103 and bill the fused boundary (retires the unfused-approximation exception) #1580

Description

@tianhaox

Retirement work item for the governed standards exception in collector/evidence_exceptions.yaml (expires 2026-10-31; see PR #1486 review S2).

Default rc23 serving on SM100/103 selects mHC.fused_hc (previous site post_mapping + next site pre_mapping in one autotuned pipeline), while the shipped mhc_module_perf tables measure the standalone pre/post decomposition (kernel_source: trtllm_mhc_pre_* / trtllm_mhc_post_mapping). The approximation is conservative (over-charges the boundary) with a ceiling of mHC's share of DSV4 layer cost (9-14% on b200); the actual Blackwell fused/unfused delta is unmeasured.

Scope of this issue:

  • collect fused_hc on SM100/103 at the pinned rc23 runtime (new table or variant column — producer+consumer contract change, owner approval required)
  • switch the SDK DSV4 model accounting to bill the fused boundary on Blackwell without double-counting normalization or pre/post
  • regenerate provenance and affected support-matrix rows
  • delete the standards exception entry

🤖 Generated with Claude Code

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions