Rename the intercube all-reduce identity to lrab_hierarchical_allreduce
(module, config key, distributed test) so the name reflects both levels
it implements: LRAB intra-SIP (local reduce to center root + broadcast)
and the hierarchical inter-SIP topology exchange (ring/torus/mesh).
ADR-0032 slug kept as the stable decision id; pure rename, no logic change.
Also in this batch:
- ADR-0032 (EN+KO): document the shipped center-root bidirectional reduce
(doc was stale corner-root); annotate ccl.yaml root_cube as a placeholder.
- Rename allreduce + pe2pe latency plots to descriptive, title-matching
filenames and retitle the in-plot headings; drop overview/overview_log.
- Point the PPTX image refs at the new plot names.
Doc + derived-artifact + rename only; no simulation behavior changed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Restores per-PE HBM controller partitioning that was lost in
commit 5917b34 ("Replace xbar/bridge/single-NOC with explicit
router mesh"), which had over-consolidated the per-slice HBM CTRL
into a single cube-wide ``hbm_ctrl`` connected to every router —
the opposite of what ADR-0019 D1/D4 specifies.
Builder splits ``hbm_ctrl`` into 8 ``hbm_ctrl.pe{X}`` instances per
cube, each reachable ONLY through PE_X's attaching router via the
existing ``peX.hbm`` attach metadata from cube_mesh.yaml. Cube
aggregate BW now matches the spec (8 PEs × 8 PCs × 32 GB/s =
2048 GB/s) instead of collapsing to 256 GB/s.
AddressResolver decodes the target PE from the HBM PA's hbm_offset
(``offset // slice_size``) and returns ``hbm_ctrl.pe{X}``. PathRouter
uses the existing ``_adj_local`` adjacency for same-cube PE_DMA so
the cube's own UCIe port can no longer appear as a zero-distance
shortcut between routers — local PE_DMA now traverses the mesh,
restoring the ADR-0019 D4 worked example
``PE0.pe_dma → r0c0 → … → r1c4 → hbm_ctrl``.
Tests:
- New tests/test_per_pe_hbm_partition.py: 14 tests covering
topology shape, per-PE router exclusivity, PA resolution,
single-hop local path, cross-PE mesh traversal, and end-to-end
latency monotonicity. Probe CLI now reports
pe-local < pe-same-half < pe-cross-half (was uniform 141ns).
- Existing tests updated for new node ids and replaced two
assertions that locked in the wrong consolidation:
test_noc_mesh.test_hbm_connects_to_all_routers and
test_topology_compile.test_hbm_ctrl_connects_all_routers are
now per-PE exclusivity assertions; test_routing
.test_all_pe_hbm_equidistant becomes
test_cross_pe_hbm_distance_increases_with_mesh_hops.
- test_ipcq_buffer_kind_locations.test_hbm_pe_hop_charged_at_large_payload
threshold recalibrated 4000→1500 ns: the prior figure reflected
serialization on the over-consolidated single hbm_ctrl; per-PE
partitioning removes that artificial contention so the gap
shrinks to the genuine PE↔HBM-hop cost.
Full suite: 645 passed, 1 skipped.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Allreduce + pe2pe + ipcq + pe_view auto-regenerated by test sweeps
running against the new chunk-streaming wire timing (per-flit
wormhole) — absolute numbers shift upward to reflect bottleneck-link
transit charged once per flit (instead of the previous cut-through
subtraction at HBM CTRL).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The pe2pe overview compared IPCQ (tl.send + tl.recv) against raw DMA
(tl.load + tl.store), but DMA is one-sided — DST never reads — while
tl.recv pays a slot-read on DST. The comparison was unfair: IPCQ
looked slower partly because it does more work.
Adds tl.recv_no_consume() — a separate, diagnostic-only entry point
that blocks for slot arrival but skips the slot-read (and bank-hop)
charge on DST. Production tl.recv is unchanged (no `consume` kwarg
on the public API), so the diagnostic flag can never accidentally
leak into real workloads.
Updates test_pe_to_pe_latency to call tl.recv_no_consume so the
overview.png shows IPCQ no-consume vs raw DMA on equal footing.
Also fixes PLOT_DIR back to docs/diagrams/pe2pe_latency_plots/
(was lost in a merge). Adds scripts/replot_pe2pe.py for label-only
re-renders without re-measuring.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Move the algorithmic root cube from the corner (cube_w-1,
cube_h-1) to the geometric center (cube_w//2, cube_h//2) and
have each phase converge bidirectionally so the intra-SIP
critical path drops from ~12 hops to ~8 hops on a 4×4 mesh
(left half W→E + right half E→W in row reduce; top half N→S +
bottom half S→N in col reduce; mirrored on broadcast).
Result on torus_2d 6 SIPs at 96 KB / PE on TCM:
before (corner root) : 22.0 µs
after (center root) : 17.2 µs (−22%)
Same shape on ring_1d (−7%) and mesh_2d_no_wrap (−12%); also
holds across SRAM and HBM (~−20% each).
Phase 1 test (test_intercube_root_center.py) asserts the
torus_2d 96 KB latency drops below 20.5 µs and that all 96
cubes still validate (correctness preserved).
Plot updates:
- overview.png: replace constant 10.6 µs theoretical line with
user-supplied hand-derived curve (per-cube packet count =
bytes_per_pe × 8 PEs ÷ 128 B; 1346 ns startup + 1.20 ns/pkt).
- All summary.csv numbers and per-topology PNGs regenerated.
- pe2pe_latency_plots and ipcq diagram emitter PNGs refreshed.
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>
mukesh
ywkang