ADR-0064 Revision 2 review fixes:
- D7 NEW: composite size cap (MAX_COMPOSITE_LOGICAL_BYTES default 1024
bytes). Oversized recipes deterministically segmented into N
CompositeCmds; each segment incurs its own dispatch cost. Models real
HW limits (descriptor queue entry, scheduler parser buffer, command
SRAM) and prevents the model from rewarding pathologically-large
fused composites.
- D2: type-aware extra-field byte counting (int/float=4, bool=1,
tuple/list=1+4N, str=1) — replaces uniform 4 bytes per extra.
- D3: recalibrated defaults to FIXED=40 cycles, R=0.0625 cycles/byte
(16 B/cycle — typical on-die descriptor queue width); anchor stays at
~43 ns for typical 1-OpSpec composite. Clarified anchor description:
DMA stages do not appear in logical_bytes (auto-inserted by
PE_SCHEDULER from operand.space per ADR-0065 D4).
- D4: removed clock_freq_ghz from pe_cost_model: override block;
conversion uses the PE node's existing clock_freq_ghz attr. Added
max_composite_logical_bytes knob.
- Context: emphasized command-count reduction (FIXED) as the primary
signal; byte term as secondary refinement.
- Open review: added large-composite scheduler-cost stress test.
- Test req: added composite-size-cap (#8) and R-sensitivity sweep (#9).
ADR-0065 + DDD-0065 follow-on updates:
- opt2 vs opt3 dispatch ratio updated 2.4× → ≈4.0× under new defaults
(FIXED-dominated, reflecting the corrected framing).
- Test req #9: decode opt2 composite fits within 1024-byte cap; no
segmentation needed for the GQA workload.
- DDD §6: TLContext lowering checks logical_bytes against cap (step 8).
- DDD §11: performance model recomputed with new defaults + sensitivity
table across R ∈ {0.25, 0.0625, 0.03125} confirming opt2 < opt3 holds.
- DDD §9 P6 gate: ratio band 2.4×±10% → 4.0×±15%; sensitivity sweep added.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three logically distinct changes, bundled for atomic test green:
1. **P3c — prefill_long tile-granular Ring KV** (ADR-0060 §5.5.1 amendment).
Convert the ring from slice-granular (one full ``(d_head, S_local)``
KV slice per step) to tile-granular (``n_tiles`` tiles of
``TILE_S_KV`` per step). Nested loop with outer tile, inner ring step:
each tile propagates through all C ring positions before the next
tile starts, so IPCQ in-flight depth stays at 1 per direction.
Bootstrap at ``(t=0, k=0)`` outside the scratch_scope establishes the
persistent ``(m, ℓ, O)``; every other iteration scope-wraps + persists
via ``copy_to``. Per-rank persistent scratch shrinks to ~1 KB; per-tile
scope bounded by TILE_S_KV regardless of S_local. Headline:
prefill_long now completes at S_kv=128K (previously overflowed).
New: ``tests/attention/test_gqa_prefill_long_tile_ring.py``
(3 tests — ceiling-lift + tile-granular ipcq_copy count +
per-CUBE distributed output regression guard).
2. **Rename ``gqa_*`` → ``gqa_attention_*``** across kernel files,
function names, and importers. The "attention" name makes the role
explicit (GQA is grouped-query attention) and matches upstream Triton
FlashAttention naming conventions. Renames:
_gqa_decode_long.py -> _gqa_attention_decode_long.py
_gqa_decode_short.py -> _gqa_attention_decode_short.py
_gqa_prefill_long.py -> _gqa_attention_prefill_long.py
_gqa_prefill_short.py -> _gqa_attention_prefill_short.py
And function names ``gqa_<phase>_<context>_kernel`` →
``gqa_attention_<phase>_<context>_kernel``. Updated 1 bench file
(milestone_gqa_headline.py) and 10 test files.
3. **ADR-0060 / 0062 / 0063 / 0064: Proposed → Accepted**.
All four are reflected in production code and covered by tests:
- ADR-0060 (GQA fused attention): 4 kernels deployed; §5.5.1
amendment added for the tile-granular Ring KV introduced by P3c
(EN + KO mirror).
- ADR-0062 (lazy tl.load): LoadFuture + _await_pending live in
tl_context.py.
- ADR-0063 (tl.scratch_scope + tl.copy_to): used in every chain
reduce + tile sweep + ring step. EN-only previously; KO
translation authored as part of this commit (CLAUDE.md
bidirectional rule).
- ADR-0064 (per-op-type CPU issue cost): cpu_issue_cost.py +
issue_cost_table wiring in tl_context.py (Phase E).
Files git mv'd from docs/adr-proposed/ to docs/adr/ (EN) and
docs/adr-ko/ (KO). ADR-0061 (tl.broadcast) stays Proposed — no
implementation; documented as optional convenience primitive in
the ADR itself.
Tests: 88/88 focused regression green
(tests/attention/ + Phase E + TL discipline).
ADR pair verification: ``python tools/verify_adr_lang_pairs.py`` OK.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Land the new GQA fused-attention kernels (ADR-0060) for prefill/decode
across long and short context, the TL discipline primitives they depend
on (ADR-0062 lazy load, ADR-0063 scratch_scope + copy_to), and the
per-op-type CPU issue cost model (ADR-0064). Remove the pre-ADR-0060
mesh-attention baseline now that the unified kernels supersede it.
ADR-0060 (long context)
- _gqa_decode.py: M-fold + 2-level chain reduce-to-root (Level-2
intra-CUBE row-then-col + Level-1 inter-CUBE) — root-only output.
- _gqa_prefill.py: head-parallel + Ring KV rotation around C CUBEs,
online-softmax merge per ring step, per-CUBE distributed output.
- Each merge stage wraps in scratch_scope() and persists running
(m, l, O) via copy_to() to lift the 1 MiB scratch ceiling.
ADR-0060 §B.split.2 (short context, kv_per_cube in {1,2,4,8})
- _gqa_decode_short.py / _gqa_prefill_short.py: no cube-SP; each CUBE
owns whole KV heads; PE-parallel heads with intra-group chain
reduce. Prefill has no Ring KV (each head fully resident).
ADR-0062 (lazy tl.load): future-bearing TensorHandle, auto-wait at
first consuming op (dot/MATH/store/send/copy_to/composite).
ADR-0063 (tl.scratch_scope + tl.copy_to): scoped per-tile arena with
copy_to writeback primitive for persistent running state.
ADR-0064 (CPU issue cost model)
- common/cpu_issue_cost.py: per-op-type table (composite=40 ns,
primitives=5 ns); ratios are load-bearing per D1.
- TLContext: issue_cost_table param; _emit_dispatch_overhead(kind)
consults table with dispatch_cycles fallback (ADR-0046 §D6
back-compat).
- Live PE_CPU paths (greenlet + legacy) construct TLContext with
DEFAULT_CPU_ISSUE_COST so saturation lever (ADR-0060 §1) is
measurable end-to-end.
P7 headline bench: milestone-gqa-headline writes per-panel
op_log_summary to 1H_milestone_output/gqa_headline/sweep.json. No
figure renderers yet (deferred).
Removals (pre-ADR-0060 baseline now superseded):
- benches: _attention_mesh_kv.py, _attention_mesh_mlo.py,
_attention_mesh_mlo_2d.py, milestone_gqa_llama70b.py
- tests: test_attention_*, test_mesh_*, test_milestone_gqa_llama70b
- topology: llama70b_4sip.yaml (only consumer was the deleted diag)
- artifacts: 1H_milestone_output/gqa/ (sweep.json + 5 PNGs)
- tests/gqa/ plot helper + test (broken on Windows Tcl/Tkinter)
- ADR-0060/0061 references to deleted file paths cleaned up
(EN + KO kept in sync).
Tests: 124/124 focused regression green (attention + Phase E + TL
discipline + triton_emu + pe_components). Full regression: 764 pass,
2 pre-existing test_bench_registry failures (stale EXPECTED_NAMES
across multiple benches, not introduced here).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Per review:
- Placement unified to *contiguous* C×P blocks throughout (S0/S2.1/S2.2/S0.5);
round-robin demoted to the rejected alternative. Adds driver SP-enable
threshold fallback (smaller C / C=P=1 for short/early decode).
- Ring-vs-reduce cost model in S5.5: reduce ~ G*T_q*log(C*P) (O dominant;
m,l scalars), ring ~ 2*S (total K+V bytes a CUBE injects over C-1
rotations; recv_async pipelines so latency ~ max-step) -> ring wins when
T_q > 2S/(G*log(C*P)).
- opt3 'removes the bubble' -> 'hides (subject to scheduler+engine balance)'
everywhere; table 'hidden*' with footnote.
- 'rank' defined (SP participant = a PE in a CUBE, KV shard in its HBM->TCM).
- out-proj handoff contract (S0.5.4); S11 gate-type note (absolute latency
deferred to ADR-0064; structural + relative-to-baseline gates now).
- greenlet-as-contrast tightened to 'primitive-op (tl.dot) path' (S1, SB).
KO mirror synced; DDD gets the SP-enable threshold fallback. Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
DDD-0060 was rewritten to the two-kernel composite-hybrid design, so SB
item 1 ('DDD not yet synced') is stale. Update EN + KO mirror to record the
DDD as synced (ADR authoritative, DDD = impl how-to). Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Supersede the old greenlet-primitive/load_async/single-kernel DDD. Align to
ADR-0060's composite-hybrid + hierarchical CUBE-Group SP with two kernels:
decode+SP (head-replicated, contiguous C×P static shard, 2-level
reduce-to-root) and prefill+SP (1 Q head/CUBE, Ring KV, no reduce). Updated
file plan (lazy tl.load, scratch_scope, broadcast-opt; evolve
_attention_mesh_mlo_2d/_kv; DPPolicy.cube_start; llama70b_4sip.yaml),
placement (contiguous shared KV), phase plan (P1..P8), verification, perf
model, risks, glossary. Defers design rationale to ADR-0060 (now
authoritative); open items point to ADR-0060 §B. ADR-0064 cost model noted.
Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Regenerate the KO mirror to match the current EN: two SP kernels
(decode=reduce / prefill=ring), TL;DR full code for the 3 decode variants
+ prefill, 'Q replicated / M-fold' and '1 Q head per CUBE' terminology,
contiguous shared KV layout, opt2 tl.wait, and all SB items. Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The ex_composite #2 updates acc=(m,l,O) asynchronously on the scheduler and
the kernel never reads its output, so no auto-wait fires; acc is only final
after the last #2 in the serial chain. Add tl.wait() (drain all composites)
before hierarchical_reduce_and_store reads acc. opt1/opt3 don't need it
(their composite outputs are consumed in-iteration -> auto-wait). Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The ring rotates K/V over IPCQ, so they must be kernel-held TCM handles
(tl.load), not HBM tl.ref streamed inside the composite. Correct the
prefill kernel: load K pre-transposed [d, S/C] and pass the TCM-resident
Kc/Vc directly to the composite (drop the bogus tl.ref(Kc,(d,TILE_S)) and
TILE_S); recv shapes match ([d,S/C] for K, [S/C,d] for V). Comments note
why K/V live in TCM. Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Move the 3 decode CPU-pipelining variants (opt1 current / opt3 sw-pipe /
opt2 ex_composite) up into the TL;DR as full standalone kernels alongside
the full prefill ring kernel, with the comparison table. S5.6 is reduced to
a brief anchor (still referenced by S8/SB) pointing to the TL;DR code +
keeping the recommend/cost-model linkage. Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The prior commit updated S0/S10/S5.5 terminology and added S5.6 (3 decode
variants) but left the TL;DR with the old 'all G heads replicated' wording
and no pointer to S5.6. Sync the TL;DR: 'Q replicated (G heads stacked into
the GEMM M-dim, M-fold)', '1 Q head per CUBE', and a one-line pointer to the
3 CPU-pipelining variants in S5.6. Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- Terminology: 'Q replicated' (all G query heads stacked into the GEMM M-dim;
M-fold explained) for decode; 'one Q head per CUBE' precise for prefill.
- New S5.6: three decode CPU-pipelining variants — opt1 current CompositeCmd
(has GEMM-engine bubble), opt3 software pipelining (issue next Q.Kt before
this tile's softmax; Sj in persistent double buffer; ships now, no new cmd),
opt2 ex_composite split into two (#1 = existing GEMM+scale reads K first;
#2 = softmax+P.V+accumulator merge, the only new flash-epilogue machinery,
gives DMA K-before-V priority). MATH engine already has max/sum/exp — the
new part is the stateful flash accumulator, not the ops.
- S2.1/SB: shared prefill/decode KV layout = contiguous CxP blocks (prefill
causal-skip needs contiguous; avoids prefill->decode reshard; short-context
under-use caveat). S8 item 4 sizing note for the two-composite split.
Prefill note: opt2/opt3 give little for prefill (causal if can't enter a
composite; recv_async already overlaps). Docs only; KO mirror deferred.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Decode-SP and prefill-SP are structurally different and cannot share one
kernel (principle: move the smaller thing):
- Decode: O=[G,d] tiny, KV cache big -> keep KV statically sharded/resident,
G heads replicated (M-fold), move only (m,l,O) via the 2-level reduce (S4).
- Prefill: O=[S,d] big -> shard heads (1 query head per CUBE, C=G),
rotate KV (Ring KV, S5.5), no (m,l,O) reduce; each CUBE writes its own head.
Rewrites TL;DR (two kernels), S0 (head map differs by case), S0.5.4 (output
head distribution differs -> downstream out-proj impact), S4 (scoped to
decode; S4.1 = intra-CUBE KV-split + PE reduce, the only way decode uses P
PEs), S5.1 (decode skeleton), S5.5 (head-parallel Ring KV), S9/S10/S11, and
adds SB items (two head mappings, output asymmetry, prefill within-CUBE PE,
C=G coupling, reconcile with _attention_mesh_mlo_2d). KO mirror deferred
until the design stabilizes (adr-proposed is mirror-exempt). Docs only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Placement pivot (user-approved): a CUBE Group = C CUBEs within one SIP that
jointly own one KV head + its G=8 query heads. KV sequence sharded 2 levels
(Level-1 inter-CUBE over C, Level-2 intra-CUBE PE over P=8 = C*P ranks); G
folded into matmul M. C is a knob (8/4; C=1 = single-CUBE). Reverses the old
'a query head never spans CUBEs' non-goal (held only because the baseline
was H_kv=1). device=SIP; the for-kv loop is gone (head picked by CUBE coord).
Reduction is a 2-level reduce-to-root (not all-reduce): Level-2 PE tree ->
Level-1 center-root CUBE-mesh reduce, adapting lrab_hierarchical_allreduce's
inter-CUBE pattern as reduce-only + log-sum-exp. Data-driven (send on local
P.V completion, no global barrier) + level-pipelined; per-level topology
configurable (tree for decode, ring for long prefill).
Rewrites SS0/2/4/5/0.5/8-11, pseudocode, and adds SSB items (4-SIP config,
mesh partition, C knob, invariant-reversal check, index-math test). KO mirror
updated. Topology grounded in topology.yaml (4x4 CUBE mesh/SIP, 8 PE/cube).
Docs only; no production code changed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- ADR-0060: GEMMs (Q.Kt, P.V) via existing tl.composite (scheduler-managed
tiling + K/V DMA streaming); softmax merge + IPCQ tree reduction stay in
kernel. Front TL;DR pseudocode of the final composite kernel; new section
B lists open design items (DDD sync, K pre-transpose, dma_read lever,
kernel-vs-scheduler tiling, ring path).
- ADR-0062: redefined from a new load_async op to global lazy tl.load
(non-blocking + auto-wait on first use; API unchanged; goldens regenerate).
- ADR-0064 (new): per-op-type CPU issue cost model (composite ~40ns >>
primitive) so the hybrid's CPU-saturation win becomes measurable
(currently dispatch_cycles=0 hides it). Cost-model impl deferred.
- KO mirrors for ADR-0060/0062/0064 (-ko suffix, adr-proposed).
Rationale: non-blocking CompositeCmd offloads tiling to PE_SCHEDULER,
decoupling CPU issue-rate from execution so the CPU can saturate the
engines; the prior 'composite = no latency benefit' claim was an artifact
of dispatch_cycles=0. Docs only; no production code changed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Verified against sim_engine data path (memory_store, data_executor):
- GQA reuse does NOT need a broadcast op. The baseline's h_q==h_kv limit
is its head-packing reshape hack, not a missing primitive. Correct fix:
per-KV-head loop with G folded into matmul M dim (byte-conserving
reshape) — runs today, timing correct (m=G*T_q), data mode runs.
- ADR-0061 broadcast demoted from 'the blocker' to optional convenience.
- Surfaced tl.trans = reshape-not-transpose (memory_store reshapes;
data_executor np.matmul on reshaped operands) -> numeric parity is
bounded; verification is structural/timing/determinism-first (matches
SPEC perf-model purpose). Optional tl.transpose deferred.
- Reordered DDD phase plan (P1 GQA needs no new feature; P3 scratch_scope
is the key scale feature); added open decisions 10.10 (transpose) and
10.11 (GQA-via-M-fold finding).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Reframes the proposed GQA FlashAttention design onto kernbench's actual
execution model (greenlet tl API + IPCQ), replacing the composite-centric
mechanism that does not match the simulator:
- Records relationship to existing baseline kernels (_attention_mesh_kv/mlo,
milestone-gqa-llama70b) and their 3 deliberate limitations.
- Mechanism is greenlet tl (per-op latency; no fusion benefit), not
composites; running (m,l,O) is Python handles; reduction is tl.send/recv.
- Tree reduction (log N) replaces baseline all-to-all fan-out (N-1).
- Pseudocode rewritten in real tl.* signatures; depends on ADR-0061/62/63.
- Rejects composite-IPCQ-push + composite-carried-state + flash-composite
with documented efficient alternatives.
- Adds verification plan.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Proposed prerequisites surfaced while evaluating the GQA fused-attention
ADR against the actual kernbench tl/sim_engine implementation:
- ADR-0061 tl.broadcast: data-faithful GQA head reuse (fixes the
MemoryStore nbytes check that forces h_q==h_kv==1 today).
- ADR-0062 tl.load_async: non-blocking HBM tile load for KV prefetch
(KV-load-bound decode/long-context overlap).
- ADR-0063 tl.scratch_scope: per-tile scratch recycling (removes the
1 MiB bump-allocator ceiling that caps context at S=16).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
ywkang
mukesh
Yangwook Kang