mukesh
f6d262e359
Two related issues caused measured pipeline efficiency to look worse than the simulator's actual behavior: 1. DMA timing recorded too early. The op-log start timestamp for a DMA op fired when the request entered the queue, and the DMA channel was released as soon as the request was issued. Back-to-back DMAs therefore appeared to grab the channel simultaneously, with per-op duration drifting upward as queue depth grew - an artifact, not real cost. Fix: defer the start timestamp until after the channel is acquired, and hold the channel through the full HBM round-trip until the response returns. Per-op duration is now constant and equal to the actual transfer interval; serialization is visible as queue wait, not as inflated service time. 2. Sweep timing window folded in pre-composite work. The PE timing window spanned every PE engine record, which included the upfront pinned-operand DMA issued before the composite GEMM begins. For large-K shapes that one-shot load can be nearly half of the window, conflating operand-staging cost with composite-pipeline behavior. Fix: add a second window scoped to the composite pipeline by filtering op_log records to those tagged with a tile-pipeline stage; the legacy operand-load path is untagged and naturally excluded. For 32x3072x32 load_ref the window drops from 1765ns to 992ns and measured eff lines up with the steady-state DMA-bound stage limit instead of being penalized for the one-time load. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Generated Diagrams
This directory contains diagrams generated from topology compilation.
What these files are
- Derived artifacts generated from:
- compiled topology graph
- distance (accumulated latency) metadata
- view/layout rules (ADR-0005)
These files are meant for quick visual inspection and review.
Default outputs
- SIP view:
sip_view.mmd(and/orsip_view.dot) - CUBE view:
cube_view.mmd(and/orcube_view.dot) - PE view:
pe_view.mmd(and/orpe_view.dot)
How to preview
- In VS Code:
- open
.mmdor.mdcontaining Mermaid blocks and use Markdown Preview - for
.dot, use a Graphviz preview extension ordot -Tpng
- open
Notes
- Diagrams are representative and distance-aware by default.
- Instance indices are not required unless debugging asymmetry.
- Outputs should be deterministic for the same topology and rules.