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>
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>
Add intra_N/S/E/W to install.py _OPPOSITE_DIR table so the intra-cube
PE-to-PE namespace is symmetrical with intercube N/S/E/W. ADR-0032
documents the intercube allreduce algorithm (supersedes ADR-0029).
Refresh ADR-0024/0025/0029 cross-refs and update
test_intercube_sfr_config.py to cover the new intra_* mappings. Drop
the obsolete test_ccl_round_robin_recv.py (replaced by intercube tests).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
mesh_2d, torus_2d, and mesh_2d_no_wrap accept optional w,h kwargs;
sqrt fall-back preserved for square layouts (back-compat tests
confirm 4-SIP and 9-SIP square configs still work). sfr_config
reads system.sips.w/h from spec and threads dims through to the
topology fn.
test_allreduce_multidevice CONFIGS switched from 4 SIPs (square)
to 6 SIPs: ring_1d_6sip, torus_2d_6sip_2x3, mesh_2d_no_wrap_6sip_2x3.
_write_temp_configs writes system.sips.w/h when supplied;
_sip_topo_dims reads them back. Latency sweep loop also moved to
6-SIP layouts. Linear-scale plot variants dropped -- only log-scale
*.png + summary.csv emitted. Plots in tests/allreduce_latency_plots
regenerated.
New tests/test_sip_topology_rectangular.py asserts neighbor
correctness for 2x3 layouts and back-compat for square fallback.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2-rank bidirectional ring deadlock: when E and W neighbors point to the
same peer, sender-coord matching in _handle_meta_arrival / _credit_worker
picked the first direction in dict order, landing data in the wrong rx
slot relative to what the kernel recv(W) was waiting on.
Fix (ADR-0025 D1/D2/D3):
- install.reverse_direction: prefer OPPOSITE direction (E↔W, N↔S) when
peer has it pointing back to us; fallback to any matching for
topologies without opposite convention (tree_binary parent/child).
- _handle_meta_arrival: match by token.dst_addr range against each qp's
my_rx_base_pa + n_slots × slot_size window (unambiguous).
- _credit_worker: match by credit.dst_rx_base_pa == qp.peer.rx_base_pa.
- IpcqCreditMetadata: new dst_rx_base_pa field carrying receiver-side
rx base; _delayed_credit_send fills it from the consuming qp.
Tests (Phase 1 → Phase 2):
- test_reverse_direction_opposite_preference_2rank_ring
- test_reverse_direction_opposite_preference_4rank_ring_sanity
- test_meta_arrival_matches_by_dst_addr_same_peer
- test_credit_matches_by_dst_rx_base_pa_same_peer
- Existing credit-return test updated with dst_rx_base_pa.
508 tests pass.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Tensor.__setitem__ / __getitem__:
- Shard-aligned slice assignment and read on deployed tensors.
- Scalar broadcast and numpy array assignment supported.
- Cross-shard slices raise NotImplementedError (use copy_ for that).
- 3 new tests: single-PE, multi-PE, cross-shard error case.
Hierarchical all-reduce kernel (src/kernbench/ccl/algorithms/):
- 3-level reduce: intra-cube (E/W) → inter-cube (N/S) → inter-SIP (parent).
- Bidirectional ring reduce at each level: ceil((N-1)/2) rounds.
Left half sends via dir_dec, right half via dir_inc (wrap).
Representative receives from both sides.
- Chain broadcast for reverse path: cube 0 PE 0 → all PE 0s → all PEs.
- Registered in ccl.yaml as "hierarchical_allreduce" with topology: none
(neighbors() override builds the full 3-level neighbor map).
- kernel_args derives pes_per_cube/cubes_per_sip/num_sips from world_size.
- Mock-verified at 8/16/32/64/128 ranks.
Mock runtime fixes:
- Direction pairing: explicit N↔S, E↔W, parent↔parent instead of
"first matching reverse". Fixes 2-element rings where N and S both
point to the same peer.
- Deadlock detection: send-counter based (not just queue-depth-total)
to catch chain reductions where send+recv pairs net to zero.
- Multi-cube program_id: pes_per_cube parameter enables
program_id(axis=0) = PE within cube, program_id(axis=1) = cube id.
Legacy single-cube tests unaffected (default = world_size).
504 tests pass in 12s.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
mukesh
ywkang