The collaborator commit 7c346de added the comparative figures
(gqa_decode_long_ctx_4cases_{latency,memory,traffic}.png) but the
fused-GQA section still only referenced the four headline panels.
This commit closes that loop:
- New §6 subsection "Long-context decode: parallelism strategies"
added between Results and Analysis. It lays out the four
parallelism strategies (Cube-SP/Repl x PE-TP/SP) and pulls in the
three new figures.
- The discussion highlights the central trade: the fastest strategy
(Case 3, Cube-Repl x PE-SP at 20.2 us) requires replicating the
full KV cache to every CUBE, while Case 4 (Cube-SP x PE-SP, the
chosen design marked *) gives back ~14 us in exchange for an 8x
KV-memory reduction. Case 4's ~190 IPCQ copies + ~190 DMA reads
are precisely the on-device collective traffic PE_IPCQ and the
torus links of §5 are provisioned to absorb -- a direct payoff
of the communication-side codesign work.
- Connects back to §5 (PE_IPCQ / all-reduce) so the reader sees the
capstone arc: the GEMM enabler exposes the data-movement bound,
the communication enabler attacks it, and the long-context
parallelism study shows how the choice between the two extremes is
framed by KV memory vs. on-device collective traffic.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
§2 platform:
- Add a "memory-centric AHBM" sentence to the device-and-execution
intro: each PE is paired with dedicated HBM bandwidth and on-PE
TCM, so the performance question is about feeding compute from
locally-attached memory + moving the unavoidable inter-PE traffic
efficiently. Makes the AHBM character of the platform visible
before §2.3 starts unpacking the latency model.
- Promote "Congestion and contention modeling" from \paragraph to
\subsubsection: this is the platform's core differentiator over a
peak-BW roofline, so it deserves its own heading.
- Rename "Control-plane (issue) cost model" to "Command dispatch
overhead model" -- describes what it actually charges (the PE_CPU
paying a fixed + per-byte cost to push a command to one of the
accelerator engines) without the more abstract "control-plane"
framing.
- Add a third Accuracy cross-check from kernbench probe: a
PE→HBM DMA-distance sweep that confirms monotonic hop progression,
bandwidth saturation matching the per-edge model, and the built-in
invariants (D2H >= H2D, cross-CUBE best < worst). New
Table~\ref{tab:probe-pe-dma} reports per-traversal latency and
utilisation at 32KiB / 1MiB across five hop classes.
- Captured probe output as figures/probe_pe_dma_summary.txt for
reproducibility.
§5 PE_IPCQ / all-reduce:
- Re-ran milestone-1h-ccl on current sim_engine (post-ADR-0064 Rev2
and the IPCQ slot-wrap Phase-2 race fix). Updated the topology-
comparison table and the buffer-kind caption to the fresh raw
latencies. Headline ratios are preserved:
torus vs mesh saving at 96 KB/PE: 24.8% (was 24.8%) -> ~25%
torus vs ring saving at 96 KB/PE: 19.3% (was 19.3%) -> ~19%
TCM vs HBM saving at 64 KB/PE: 13.4% (was 13.9%) -> ~13%
TCM vs SRAM saving at 64 KB/PE: 37.2% (was 38.3%) -> ~37%
The Executive Summary's "up to ~14%" / "up to ~38%" framing stays
consistent with these post values.
Artifacts refreshed in src/kernbench/benches/1H_milestone_output/:
- ccl/summary.csv + per-topology PNGs + buffer-kind CSV/PNG
- ccl/comparison_mesh_vs_ring_vs_2DTorus_vs_theoretical_vs_fsim.png
- gemm/* (re-run yields identical pe_window structure; PNGs
refreshed)
Paper figures synced to the fresh artifacts:
- figures/allreduce_comparison.png
- figures/allreduce_buffer_kind.png
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Generated by scripts/paper/paper_plot_gqa_decode_long_ctx_4cases.py
from the bench's sweep.json (S_kv=8192, the headline 128K run was
sidestepped — Case 2's single-PE 128-tile sweep is the long pole
and shape/ordering is preserved across scales).
gqa_decode_long_ctx_4cases_latency.png end-to-end latency / case
gqa_decode_long_ctx_4cases_traffic.png ipcq / dma op-count breakdown
gqa_decode_long_ctx_4cases_memory.png KV bytes per cube (slide-11)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
- Reordered §2 subsections to follow the SIP → CUBE → PE → graph
flow: Why KernBench → Device and execution model → Latency model
→ Modeled hardware configuration. Readers now meet the device
hierarchy before the graph abstraction that re-uses it.
- §2.2 Device and execution model: starts with the SIP/CUBE/PE
hierarchy paragraphs (each anchoring fig:sip-arch, fig:cube-arch,
fig:pe-arch); then the runtime-API/sim-engine/components bullet
list; then the atomic-vs-composite command distinction (corrects
the prior over-narrow framing that read every PE command as
composite -- atomic single-engine commands exist too, and PE_CPU
itself runs control-plane work directly).
- §2.3 Latency model: opens with the four-contribution decomposition
(per-node overhead, per-edge transmission, drain, queuing delay)
and the latency_model schematic; retains existing The hardware as
a graph / From graph to DES / Latency contributions / Congestion
/ Control-plane cost model / Accuracy paragraphs. Accuracy
paragraph now closes on KernBench's sufficiency for *relative*
HW/SW design trade-offs given analytic + external-simulator
agreement.
- New figures and assets:
- figures/sip_architecture.pdf (SIP-level graph view)
- figures/cube_architecture.pdf (CUBE-level zoom-in)
- figures/latency_model.png (conceptual latency-model
schematic with per-node /
per-edge / drain / queuing-delay
colour coding)
- figures/pe_architecture.png (carried over)
- Source-of-truth generator for the latency schematic:
scripts/paper/paper_latency_model_diagram.py (a report-only
harness under scripts/paper/ per the /paper isolation rule).
- main.tex preamble: \usepackage{tikz} added (kept from prior
sequence-diagram draft -- harmless now that the latency model is
a PNG; left in to keep paragraph numbering stable).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Mid-pass through §2. Captured progress so far:
- §2 intro previews the three new threads (graph view, DES engine,
congestion) the rewritten latency section weaves together.
- §2.3 retitled to "Latency model: a graph traversed by events" and
restructured into bold-led paragraphs:
- The hardware as a graph (nodes = components, edges = links).
- From graph to discrete-event simulation (node/edge events,
deterministic ordering, correlation-ID trace).
- Latency contributions (per-node fixed, per-edge size-aware,
per-service occupancy).
- Congestion: per-edge FIFO BW occupancy, HBM per-PC parallelism,
component serial workers — the mechanisms that surface real
bottlenecks instead of peak-BW roofline.
- Control-plane cost model (FIXED + b·R) — unchanged.
- Accuracy: extended with a second cross-check from the all-reduce
study (torus vs. analytic startup-plus-per-packet model + FSIM
external single-device reference). Existing GEMM analytic-vs-
measured 10-20% check retained.
- §2.4 Hardware-configuration table unchanged.
Still TODO: cross-check accuracy numbers against a fresh
milestone-1h-gemm/ccl re-run; the current artifacts predate the
ADR-0064 Rev2 cost-model and IPCQ Phase-2 race fix and may need a
refresh before §2.3 final lock-in.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- §1 Introduction rewritten with AHBM-first opening, in-paper KernBench
platform overview, GQA motivation and three architectural requirements,
three matching HW-SW co-design mechanisms (GQA-aware placement,
PE_IPCQ, composite-command GEMM under PE_SCHEDULER), broader-
applicability outlook (PE_IPCQ as collective substrate, composite
command for fused operator pipelines), and outline. Consistent with
the Executive Summary structure.
- Executive Summary: extended broader-applicability closing with a
forward-looking line previewing FFN/MoE integration.
- §5 section heading renamed from
"All-Reduce Acceleration via PE_IPCQ" to
"PE_IPCQ and Collective Communication".
- Title page date line refined to "2026 H1 Report".
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
New `/paper` slash-command skill that synthesizes ADR/SPEC content and live
KernBench benchmark results into a sectioned LaTeX technical paper compiled
to PDF with Tectonic (auto-installed). The skill negotiates a TOC, grounds
every number in committed artifacts or fresh bench runs, and keeps
report-only benches isolated.
This commit also includes the first generated report:
- docs/report/1H-codesign-paper/ — main.tex + per-section .tex, figures,
toc.md contract, and the built 8-page main.pdf. Covers the platform
(source-level kernels, latency model + accuracy, HW config from
topology.yaml), GEMM via composite command, All-Reduce via PE_IPCQ, and
fused GQA combining both, plus discussion/conclusion/2H future work.
- scripts/paper/ — isolated report harnesses (not registered benches):
paper_gqa_latency.py harvests per-panel GQA end-to-end latency + engine
occupancy (the milestone only emitted op-counts); paper_plot_gqa.py
renders the GQA figures.
GEMM/All-Reduce reuse committed milestone figures/CSVs; GQA results are
generated fresh. Honest flags retained: PE_CPU dispatch cost is 0 in this
config, and the proposed two-composite softmax_merge decode is marked
designed-not-measured.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds a section-based table of contents for the 46-ADR corpus, mirroring
the /report skill's classification (Design Principles / High-level
Architecture / Detailed Architecture by component / Implementation
Decisions by topic). Generated for both docs/adr/ (EN titles) and
docs/adr-ko/ (KO titles) from one tool.
tools/generate_adr_index.py:
- Single CLASSIFICATION dict per ADR — add an entry when introducing a
new ADR; the script fails loud if any file is missing from the table.
- DETAILED_COMPONENTS lists each builtin component and the ADR(s) that
cover it (ADR-0014 appears under six PE engines; ADR-0023 under
pe_dma + pe_ipcq).
- Accepts both ":" and "—" title separators (matching ADR-0033's
existing format).
- --check mode for CI: exits 1 if INDEX.md is stale.
Also includes the docs/report/architecture-2026-1H.md generated by the
prior /report write (the public-facing architecture document; 836 lines,
76 source-attribution comments).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ywkang
mukesh