perf(evolution): ⚡ carry cross-rank queries as a width-adaptive record - #263
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Five changes to the layer-build query path, squashed because the middle three share one data structure and the first is not measurable without them. The structural cutoff is decided from a (k, d) digest carried inline rather than from the wider comparison it replaced. Cross-rank queries then travel as a width-adaptive record, dropping the fixed stride the older CompactQuery design assumed. Queries whose owner is this rank resolve from positions instead of going through the cross-rank path at all. Two further changes ride with them and are named here because a reviewer cannot revert along a mechanism the message does not mention. Sink::kStride becomes incoming_layout()/querier_layout(): ContractSink's stride was the fused width while on_response_block was called with the plain buffer and took query_phase's plain-stride default, so the two agreed only by accident, and a wrong layout reads a neighbouring record's phase -- a coefficient sign flip, not a crash. And bulk_insert gains a group-prefetched hashed path, shared by the cross-rank and self inserts. Tests cover the paths that can disagree: a dense reference implementation the sparse path is differentially compared against, the digest's tie cases, the spill boundary where a row exceeds the inline width, and the prefetched insert. OperatorIndex gains a public overflow_size() so a test can assert the dense and positional insert paths spill identically -- the claim this change rests on, and otherwise unreachable from outside the class. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Carry cross-rank queries as a width-adaptive record
pr/query-wire-v3249aee8, on PR 7 (#259)8dbe2a5. One commit, 18 files, +2569/−285.The layer-build query path carried one dense word per 64 modes per query, at a fixed stride. This replaces it with a per-term-minimal record and stops the two paths that never needed the wire from using it.
What changes
monoprop_DIGEST_CUTOFFknob.CompactQuerydesign assumed is gone.Sink::kStridebecomesincoming_layout()/querier_layout(), fixing a latent inconsistency:ContractSink::kStridewas the fused width whileon_response_blockgot the plain buffer and used the plain-stride default — correct only by accident. A wrong layout reads a neighbouring record's phase, which is a coefficient sign flip, not a crash.bulk_insertgains a group-prefetched hashed path, shared by the cross-rank and self inserts.They ship together because 2 and 3 share the
OperatorIndexposition store, and 1 is not measurable without them.Timings
Arms:
main48cadcbvs this branch, bothENABLE_PROFILE=OFF. Stacked, so this is PR 7 + PR 5 — PR 7's own timing was a null in both its campaigns (0 and 1 of 24, all inside 0.98–1.01x), and memory includes its 2 B/term.port/main, so every row below 1.00 is this branch faster. 10 interleaved reps per cell in one allocation, order flipped per (rep, cell); ratios divided per rep then median, never a ratio of medians.rungislower_atol(with Trotter steps where they differ) and separates cells that are different model sizes. No multiplicity correction — one branch against main is not a family — so everypis a raw two-sided sign test.Single thread (1 rank x 1 partition)
build_graph[hubbard]propagate[hubbard]build_graph[pauli]energy[pauli]gradient[pauli]propagate[pauli]Layouts A (1x128) and B (8x16)
build_graph[hubbard]propagate[hubbard]build_graph[pauli]energy[pauli]gradient[pauli]propagate[pauli]build_graph[hubbard]propagate[hubbard]build_graph[pauli]energy[pauli]gradient[pauli]propagate[pauli]build_graph[hubbard]propagate[hubbard]build_graph[pauli]energy[pauli]gradient[pauli]propagate[pauli]build_graph[hubbard]propagate[hubbard]build_graph[pauli]energy[pauli]gradient[pauli]propagate[pauli]Peak RSS (node sum)
hubbard-freshhubbard-freshpauli-freshpauli-graphhubbard-freshhubbard-freshpauli-freshpauli-graphhubbard-freshhubbard-freshpauli-freshpauli-graphhubbard-freshhubbard-freshpauli-freshpauli-graphhubbard-freshhubbard-freshpauli-freshpauli-graphWhat the grid shows, and where it does not
Nothing regresses at any production layout. Across P = 128 and P = 256, both models, all four operations, every resolved cell is a win (0.63–0.99x) and the rest are flat.
build_graphneeds more than one rank — and it is ranks, not partitions, since layouts A and B share the same flat world P. Both models are flat at 1 rank (1.005 7/10, 1.002 6/10) and win from 2 up, but the magnitude diverges: hubbard grows monotonically (1.22x / 1.42x / 1.59x at 2 / 8 / 16), pauli jumps once and saturates (0.938 / 0.949 / 0.947).propagatewins a flat 1.13–1.17x at every rank count from 1 to 16, all four cells resolved, so that share is not the exchange.energyandgradientare a null control inside the same cells. Neither touches the query wire; across the nine cells running them they land in 0.971–1.018, same binary, same allocation, same reps as the rows that moved.The scope limit: the record's fixed per-query cost needs something to amortise against, and at one partition there is nothing. Three of the four single-thread operations regress 1.21–1.54x, 10 of 10 reps each. This is not a narrow-system effect — pauli is the narrow model and it wins 0.92–0.95x once the problem is large (91.3M terms), so the axis is amortisation, not width. The one P = 1 gain,
build_graph[hubbard]at 1.11x, is the digest becoming visible where emit is ~67% of the layer instead of ~12%.The digest itself cannot be confirmed at 128 partitions, where it is ~0.8% of
build_graphwall — below its paired noise floor. Its independent evidence is retired instructions: 0.9128x aroundbuild_graph, 4 of 4 reps, −23.4 per emitted term — a different instrument on an earlier form of this branch, not this campaign.Bit-identity
Determinism holds only at fixed (ranks, partitions) — across partition counts the contract is tolerance-equality — so the geometry is part of the claim. 7 of 7 cells bit-identical at (R × S) in {1x1, 2x1, 2x8, 4x8} across build_graph, propagate and pauli, job
1825793, compared per rank, unmerged, byte for byte. Witnessed on the pre-re-cut form of these commits; it cannot be re-run on this base, because the gate needs each arm to supplybenches/_builders.pyfrom its own checkout and #227 moved those modules into a separate package.Gates and reproducibility
ctest -L unit249/249,-L serial248/248, and the Python MPI suite 592 passed at each of 1x1, 1x16, 2x8 and 8x16.strings -afinds noLAYERPROF/COMMPROF, confirming no profiling instrument is linked, and findsmatched_scratch_bytes, confirming PR 7 is in the base.Not reproducible from this diff. Deucalion, 2x AMD EPYC 7742 / 128 cores / SMT off / NPS4 / 242 GiB per node; a private harness that never ships; two prebuilt venvs, extension md5s
1250a27e(main) andb4e76812(this branch).