Two strands bundled as the 1H-codesign-paper refresh unit:
(A) This session — single-op cost-model reflection (depends on 2d8271c):
- §2 Table 2 (tab:hw): split "FIXED per command" into "FIXED per
single-op command" (8 cycles) and "FIXED per composite command"
(40 cycles); §2 dispatch-overhead prose updated to the two-class split.
- §3.4 (sec:gemm-vs-async): rename paragraph headers + prose to
async-full / async-tiled; "atomic" -> "single-op" throughout; reframe
mechanism #3 from the old DMA-only fast-path to the single-op
fast-path. Headline narrative now: even with EVERY single-op cmd
(96 DMA + 48 dot + 47 add) charged the light 8-cycle FIXED, composite
still wins ~2.8x at K=3072 purely on command-count structure (1 vs
192 commands) -- down from the pre-D8 ~6.3x, and explicitly NOT a
modelling artifact. Numbers refreshed from the regenerated sweep:
async-full 3.83->3.91, async-tiled 1.14->~2.53, under-tile corner
1.06->1.21, depth-2 vs depth-inf spread <1%. New figure wired in.
- build/main.pdf rebuilt (tectonic); pdftotext-verified (no broken
refs; Table 2 split, single-op terms, 2.8x/2.53/192-host-commands
all present).
(B) Prior-session paper work riding along uncommitted: §4 all-reduce
deep-edit, §5 GQA, §6 discussion trims; milestone_1h_ccl.py plot
label "FSIM" -> "H2 2025 SW queue baseline"; regenerated diagrams
under docs/diagrams/** and gemm output PNGs under
1H_milestone_output/gemm/. (Composite-window gemm plots are
unaffected by D8 — D8 only changes single-op dispatch FIXED, which
the composite window excludes.)
All TODO items for the D8 single-op extension are now complete and
pushed across 3 commits (2d8271c cost-model+ADR+tests, 821bbf2 bench
harness, this paper refresh). Full regression green (826 passed, 1
skipped). No remaining work.
NOTE for review (carried from 2d8271c): ADR-0065's "2x CPU-offload win"
headline for GQA decode opt2 may want a refresh to the post-D8 ~1.87x.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Extend tl.composite() with an ordered epilogue list. Each op carries
a scope flag - output_tile (default, runs once per (m,n) before
STORE), k_tile (every K-tile right after GEMM), or kernel. Plan
generator slots MATH stages by scope; pe_math reuses pe_dma's
local-loop pattern so chained epilogues (bias->relu) skip the port
hop. op_log captures per-stage params for telemetry. Topology
gains a gemm->math edge (snapshot test updated).
API stays backward-compatible - `epilogue=` is opt-in.
Example:
h = tl.composite(
op="gemm", a=a, b=b, out_ptr=int(out),
epilogue=[
{"op": "dequant", "scale": s_per_k, "scope": "k_tile"},
{"op": "bias", "bias": bias_vec},
{"op": "relu"},
{"op": "scale", "factor": 0.5},
],
)
tl.wait(h)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Conflict resolution:
- intercube_allreduce.py: kept origin's `if single_cube:` early-exit
(TP launches kernel on one cube/rank → skip intra-SIP mesh and go
direct to inter-SIP exchange) AND replaced the multi-cube body with
the local center-root + bidirectional reduce/broadcast (8-hop
critical path on 4×4 vs 12 with corner root).
- tests/{allreduce,pe2pe}_latency_plots/: kept the local move to
docs/diagrams/; dropped origin's stale content edits to the old
paths (regenerable derived artifacts).
- docs/diagrams/pe2pe_latency_plots/summary.csv: kept local
(post-Phase-2 + center-root values).
Origin contributions retained as-is:
- pyproject.toml: matplotlib >= 3.7 dep.
- runtime_api/distributed.py: derive effective cube_w/h from tensor
shard placement so single-cube TP paths get cube_w=cube_h=1.
- kernel_args() now accepts optional cube_w/cube_h kwargs.
Verified post-merge:
- test_intercube_root_center.py: 2/2 (center-root multi-cube path).
- test_tp_layers.py + test_tp_mlp.py: 10/10 (single-cube TP path).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Plot output dirs now live under docs/diagrams/ (the canonical
"derived artifacts" location per CLAUDE.md):
tests/allreduce_latency_plots/ → docs/diagrams/allreduce_latency_plots/
tests/pe2pe_latency_plots/ → docs/diagrams/pe2pe_latency_plots/
+ new docs/diagrams/ipcq_diagram_plots/ with two presentation diagrams
(ipcq_send_recv.png, ipcq_two_pe_dma.png)
New test tests/test_emit_ipcq_diagram.py renders the two IPCQ
diagrams from a static description (no simulation); it exists so
the diagrams can be regenerated reproducibly.
Path references updated in tests/test_pe_to_pe_latency.py.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ywkang
mukesh
