Adds the memory-bound mirror of the compute-bound prefill figure. New single-rank decode sweep (T_q=1, M=8) reuses the prefill_compute_bound kernels, sweeping per-rank S_kv with NO cross-CUBE reduce — isolating the local attention that the 64-way Case-6 decode masks under its reduce tail.
Finding: even memory-bound decode benefits from the composite command. Its scheduler-streamed concurrent per-tile DMAs reach ~233 GB/s (91% of the 256 GB/s per-rank roofline) while the primitive's blocking tl.dot serializes one tile DMA and plateaus at ~166 GB/s — a 25-28% latency win that widens with context. This refines the paper's 'decode is latency-neutral' claim: neutral at 64-way production scale (reduce-dominated), but the composite extracts bandwidth at the local level. The bandwidth roofline here mirrors the MAC roofline in prefill.
Adds: gqa_decode_streaming.py sweep (wired into the milestone umbrella as GQA_1H_SWEEPS=decode_streaming), paper_plot_gqa_decode_streaming.py, the figure, and a new fig:gqa-decode-stream + paragraph in 05-gqa.tex; rebuilt main.pdf. Prefill (Experiment B) re-verified byte-identical (794.1/668.1/646.9us).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Complete the composite-command study across both attention regimes and
write up the result, resolving when the composite command helps latency.
Decode (memory-bound, T_q=1, M=8): the command form is latency-neutral —
the kernel is bound by KV streaming and the MAC array is near-idle, so the
composite's only benefit here is host-issue offload (O(n_tiles) -> O(1)
PE_CPU commands). Figure: gqa_decode_long_ctx_composite (latency flat,
command count saturates).
Prefill (compute-bound, large M=G*T_q tile-filling): add three command-form
variants of a single-rank FlashAttention prefill kernel
(_gqa_prefill_compute_bound: primitive / composite / composite_extended).
Here the composite's scheduler-internal per-tile DMA<->compute pipeline
keeps the MAC array fed while the primitive's blocking tl.dot starves it,
so composite wins on MAC utilization (68% flat -> 83%) and wall-clock
(19% faster at ctx=1024), with the margin growing with context (deeper
P.V reduction = more tiles to pipeline) — the compute-bound mirror of the
GEMM result in section 3. Figure: gqa_prefill_compute_bound (latency +
MAC util). Sweep wired as GQA_1H_SWEEPS=prefill_cb; tests cover structure,
e2e, and composite<primitive in the compute-bound regime.
The synthesis: composite has two benefits set by roofline position —
host-issue offload (always) and MAC-array feeding (compute-bound only).
Decode exercises the first, prefill both.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Add two command-form variants of the Case-6 (Cube-SP x PE-SP) long-context
decode kernel alongside the primitive baseline:
- composite: per-tile GEMMs issued as one coarse tl.composite over the
full S_local (PE_SCHEDULER tiles/streams K,V) -- O(1) PE_CPU commands
vs the primitive kernel's O(n_tiles).
- composite_extended: Q.K^T composite + softmax_merge recipe composite
(ADR-0065), folding the per-tile online merge + P.V.
Extract the shared two-level (m,l,O) reduce into _gqa_mlo_reduce and
refactor the baseline to use it (byte-equal, guarded by a 64-rank
command-stream digest test).
Engine fix: _make_compute_out omitted pinned=True, so an on-chip TCM
compute result consumed as a composite GEMM operand was scheduled as an
HBM DMA_READ of its bit-61 scratch address -> PhysAddrError in data mode.
Mark compute outputs pinned (resident), matching the composite
auto-output and recipe scratch handles. .pinned is read only by the
tiling DMA gate, so this is byte-equal for existing benches.
Add the composite sweep (emit-level PE_CPU dispatch to 1M + data-mode
latency to 128K), its plot, umbrella wiring (GQA_1H_SWEEPS=composite),
and tests (refactor guard, dispatch saturation, engine-fix, e2e).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Replaces the unsourced 32 KB/layer placeholder in the analytical chart
with T*(N-1)/N where T = h_q * S_q * (d_head*2 + 8) ~ 2.1 KB
(per-PE (m, l, O) payload) and N is the participant count of the
reduce-only chain per stage. Cases 2/3/6 analytical bars now match
the simulator-measured numbers within ~10% (was 6-30x over).
Also:
- Bumps the measurement S_kv from 8 K to 64 K to verify Cases 1, 2, 3, 6
are genuinely S_kv-independent and Cases 4, 5 scale linearly.
- In-bar descriptor on the paired chart is now wrapped to fit the bar
width, black, no background box, and centered between the analytical
and measured bars so the label applies to both.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Drops the per-case panel outline from linewidth 2.2 to 0.9 with 85% alpha.
The case-color frame still anchors each panel but no longer competes
with the swimlanes, flit packets, and annotations inside.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Adds two new IPCQ architecture views in the latency_model.png aesthetic:
a 2x2 flow figure (one per case) and a 4x1 stacked figure for taller
horizontal panels. Refactors per-case panel drawing into shared helpers
and disambiguates the flit labels (HMQ desc -> Hd so it does not
collide with data D). Two-row legend keys.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Removes the (measured) comm column, widens the Notes column with
shorter wrapped text, scales the table figure down, and wraps the
heading to two lines so it sits flush with the table.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
6 generated figures comparing IPCQ (chosen) against the 3 HW alternatives
(Doorbell+Polling, HMQ, RDMA-CQ): architecture blocks, latency stack,
op counts, sequence flow, decision matrix, and control/data plane overlay.
Three figures also copied into the paper's figures/ folder for inclusion.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Filename cleanup so every long-ctx GQA artifact has a consistent
"gqa_long_ctx_6cases_*" prefix (or "gqa_decode_long_ctx_6cases_*"
for decode-only charts). Old "4cases" / mixed names retired.
Renames (long_ctx + figures, content unchanged):
gqa_hbm_budget.png -> gqa_long_ctx_6cases_hbm_budget.png
gqa_4cases_summary.png -> gqa_long_ctx_6cases_summary.png
gqa_4cases_memory_comm_analytical -> gqa_long_ctx_6cases_memory_comm_analytical.png
gqa_4cases_memory_comm_paired -> gqa_long_ctx_6cases_memory_comm_paired.png
gqa_kv_sharding_6cases_diagram -> gqa_long_ctx_6cases_kv_sharding_diagram.png
gqa_kv_sharding_6cases_table -> gqa_long_ctx_6cases_kv_sharding_table.png
gqa_3cases_measured_comm.json -> gqa_long_ctx_6cases_measured_comm.json
gqa_decode_long_ctx_4cases_*.png -> gqa_decode_long_ctx_6cases_*.png
(figures dir; long_ctx never had old)
New 4-chart 6-case set in long_ctx output dir (regenerated by
paper_plot_gqa_decode_long_ctx_4cases.py, which now reads all 6
sweep_decode.json panels — Cases 1-6 with the same colour scheme
used elsewhere: red = overflow per-PE HBM, grey = neutral, blue
= Pareto-best ★):
gqa_decode_long_ctx_6cases_latency.png
gqa_decode_long_ctx_6cases_memory.png
gqa_decode_long_ctx_6cases_parallelism.png
gqa_decode_long_ctx_6cases_traffic.png
Generator scripts updated to write the new filenames + handle the
two new d_head-TP variants (Cases 4, 5) in their per-PE memory and
active-PE-count helpers. Figure widths bumped 10 -> 12 in to fit 6
multi-line case labels.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Two new long-ctx decode attention kernels for the d_head-TP sharding
variants the 6-case chart predicts:
· _gqa_attention_decode_long_ctx_cube_sp_pe_tp_dhead.py
Cube-SP × PE-TP-d_head (Case 4 in chart). Per cube holds
S_kv/C tokens of full d_head; per PE holds same tokens but
only d_head/P dims. Partial Q·Kᵀ scores reduced intra-cube
before softmax; outer (m,ℓ,O) merge two-phase (intra+inter).
· _gqa_attention_decode_long_ctx_cube_tp_dhead_pe_sp.py
Cube-TP-d_head × PE-SP (Case 5). Per cube holds full S_kv
with only d_head/C dims; per PE holds S_kv/P of those dims.
Partial scores reduced inter-cube (UCIe) before softmax.
Sweep dispatch (gqa_decode_long_ctx_4cases.py) extended with two
new panels so the milestone-1h-gqa sweep covers all 6 cases.
Smoke test scripts/verify_case4_dhead_tp.py runs Cases 4/5/6 at
S_kv=2K to validate the kernels load and execute end-to-end.
Plus the figure-generation toolchain that produced the committed
PNGs in the prior commit (dd3337f):
· paper_plot_gqa_4cases_summary.py - 3-panel summary +
2-panel (analytical / paired-measured) chart generator.
_plot_comm now takes mode="analytical" | "paired".
· paper_plot_gqa_kv_sharding_diagram.py - 6-case 2-D KV-tensor
diagram + companion comparison-table PNG.
· measure_gqa_decode_placement_comm.py - runs all 6 kernels at
S_kv=8K, sums actual IPCQ-copy bytes from engine.op_log,
scales partial-score AR ×128 to S_kv=1M, writes
gqa_3cases_measured_comm.json (committed).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Adds the user-orchestrated async GEMM variants used in paper §3.4 to
contrast with the composite (load_ref) path:
- matmul-async : naive (tl.load full A+B, one tl.dot)
- matmul-async-chunked : depth-inf prefetch (all B-tiles queued)
- matmul-async-chunked-db : depth-2 double-buffer (TCM-bounded)
plus scripts/paper/paper_plot_gemm_async_vs_composite.py (4-way per-PE
TFLOPS sweep + figure) and the regenerated outputs under
1H_milestone_output/gemm/.
Sweep regenerated under the ADR-0064 D8 single-op cost model (commit
2d8271c). At K=3072 the composite-vs-async-tiled gap narrows from the
pre-D8 ~6.3x to ~2.8x (composite 7.18 / async-tiled 2.54 TFLOPS): D8
makes the async-tiled kernel's ~191 single-op dispatches 5x cheaper, so
its dispatch overhead drops to ~1.5us. Qualitative order persists:
composite > async-full (3.91) > async-tiled (2.54).
test_bench_registry.py: register matmul-async / -chunked / -chunked-db
(also picks up the earlier milestone-gqa-headline -> milestone-1h-gqa
rename already present in the tree).
--- Remaining work (resume here if interrupted) ---
- Paper §3.4 (03-gemm.tex sec:gemm-vs-async): finish naive->async-full /
chunked->async-tiled rename AND reframe "FIXED_DMA=8 for DMA descriptors"
to single-op(8) vs composite(40). Figure already copied to
docs/report/1H-codesign-paper/figures/gemm_composite_vs_async_tflops.png.
- Paper §3.4 K=3072 para + mechanism #3: update dispatch breakdown to new
model (191 single-op * 8c ~= 1.5us, was 4.6us) and headline gap
~6.3x -> ~2.8x.
- Rebuild build/main.pdf (tectonic) + verify via pdftotext.
- Then commit Group 3 (paper + diagrams + PDF).
- Table 2 / §2 prose / ADR-0064 D8 already done in 2d8271c.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Analytical plot generator + PNG covering the 4 sharding cases from
slide 17 plus the 2 d_head-TP variants (Cases 4, 5). Three panels:
per-PE HBM budget breakdown (Wq + Wk + Wv + Wo + 4.24 GB KV
headroom), per-PE KV memory at S_kv=1M, and per-PE communication
per output token (decode). Numbers match slide 17 (max KV context
~7.1M for the 64-way sharded cases).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Mirrors the existing decode 4-cases study for prefill on the LLaMA-3.1-70B
single-KV-head group (h_q=8, h_kv=1, d_head=128) across 8 cubes × 8 PEs:
Case 1 Cube-SP × PE-TP → KV S_kv-Ring across cubes; Q/O T_q-split 64-way
Case 2 Cube-Repl × PE-TP → full KV per cube; only CUBE 0's P PEs split T_q
Case 3 Cube-Repl × PE-SP → full KV per cube; PEs SP on S_kv (intra-cube AR)
Case 4 Cube-SP × PE-SP → KV split 64-way + Q T_q-split across cubes
(Ring KV + per-cube intra-CUBE AR) ★ optimal
Cases 2 and 3 use Q-axis tiling (TILE_Q) so the per-PE scratch is bounded
by TILE_Q × TILE_S_KV regardless of T_q (the full Q tensor would be
G·T_q·d_head·2 bytes which scales linearly with T_q and blew the 1 MB
budget at T_q≥128 without tiling).
Per-panel try/except in run_sweep tolerates per-panel failures so
sweep.json always lands with whichever cases succeed plus a failures
list. Case 4 uses configure_sfr_intercube_ring with the snake submesh
(2,4) which installs both the Ring E/W lanes and the intra_* lanes
needed for the intra-CUBE reduce — single SFR config for all 4 cases.
The plot script generates 4 PNGs (latency, traffic, memory, parallelism)
into 1H_milestone_output/gqa/long_ctx/. The parallelism chart shows
total compute work (active_PE × T_q_per_PE × S_kv_processed) — exposes
Case 3's 8× redundancy vs. Cases 1/2/4 which all do unique work.
gqa_prefill_long_ctx_4cases.py exposes run_sweep() rather than a @bench
decorator — the umbrella bench in the next commit invokes it.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Splits the GQA helpers into a dedicated subpackage to make room for the
prefill 4-cases study (next commit) and a single umbrella bench
(milestone-1h-gqa, after that).
Layout:
benches/gqa_helpers/
long_ctx/ — decode 4-cases kernels + sweep runner
short_ctx/ — prefill/decode short-context kernels
shared/ — _gqa_panel_helpers + decode_opt2 (context-agnostic)
The registry audit now skips subpackages so gqa_helpers/ (without a
leading underscore) doesn't get audited for @bench decorators.
Also drops the legacy milestone-gqa-headline bench, its
_gqa_attention_prefill_long kernel, 6 dependent prefill tests, the
paper_gqa_latency.py report harness, and the 3 stale headline-derived
PNGs the §6 wire-up referenced (paper will re-pull from the new
1H_milestone_output/gqa/long_ctx/ once §6 is updated).
The _ccl_cfg and _summarize_op_log helpers used to live in the
headline bench; extracted them to gqa_helpers/shared/_gqa_panel_helpers.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Bench changes:
- new _end_to_end_ns(op_log) and _engine_occupancy_ns(op_log) helpers
in milestone_gqa_decode_long_ctx_4cases.py (mirror paper_gqa_latency.py)
- _run_panel return dict now carries latency_ns + engine_occupancy_ns
alongside op_log_summary, so sweep.json is the single source of truth
for the comparative figures
Plot script:
- new scripts/paper/paper_plot_gqa_decode_long_ctx_4cases.py reads
sweep.json and emits 3 PNGs to docs/report/1H-codesign-paper/figures/:
gqa_decode_long_ctx_4cases_latency.png (end-to-end latency / case)
gqa_decode_long_ctx_4cases_traffic.png (ipcq/dma op counts / case)
gqa_decode_long_ctx_4cases_memory.png (KV bytes per cube / case)
Test changes:
- 2 new tests verifying the helpers + _run_panel dict shape
- lower smoke S_kv from 8192 -> 2048 (4x faster Case 2; assertions
are S_kv-independent; one fold-loop iteration preserved)
18/18 tests pass in ~4 min.
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>
The legacy panel names suggested batched serving semantics they never
had — all four modeled a single user with KV sharded differently
(C=1 single-cube; C=4 multi-cube Cube-SP), at toy dims (T_q=4, S_kv≤128).
The single-KV-group C=8 panel + the new milestone-gqa-decode-4cases
bench cover the meaningful comparisons; pytest regression already
covers C=1/C=4 configurations end-to-end at richer scale.
Changes:
- milestone_gqa_headline.py: drop the 4 legacy panels; _PANELS now
contains only single_kv_group_prefill_gqa_c8_p8. Update docstring.
- tests/attention/test_milestone_gqa_headline.py: drop the 3 legacy-
panel architectural tests (Ring-KV traffic, root-only decode write,
per-CUBE distributed output) and test_decode_panels_use_real_gqa
(no decode panels in this bench anymore). Equivalent properties
are asserted in test_milestone_gqa_single_kv_group_prefill_panel.py
(64 dma_writes, 896 ipcq_copy) and test_milestone_gqa_decode_4cases.py
(1 dma_write at cube 6, 189 ipcq_copy).
- tests/attention/test_milestone_gqa_single_kv_group_prefill_panel.py:
drop test_existing_prefill_panel_runner_backward_compat (it exercised
multi_user_prefill_gqa which no longer exists).
- scripts/paper/paper_plot_gqa.py: replace the 4 legacy _LABELS entries
with the single single_kv_group_prefill_gqa_c8_p8 label.
- Regenerate 1H_milestone_output/gqa_headline/sweep.json from the new
panel set.
Verification: 9/9 tests pass across the 3 affected test files.
Co-Authored-By: Claude Opus 4.7 <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>
ywkang
mukesh