Single-page arena ToT for all size-determinable construction (init_tiles_nested, retile)#570
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zhihao-deng wants to merge 3 commits into
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Single-page arena ToT for all size-determinable construction (init_tiles_nested, retile)#570zhihao-deng wants to merge 3 commits into
zhihao-deng wants to merge 3 commits into
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init_tiles_nested's range/fill callbacks are random-access, so the tile size is known up front. Build via arena_outer_init (one contiguous page) instead of the incremental ArenaToTBuilder, whose multi-page spill reverts the strided-BLAS fast path to per-cell AXPY. Reverts the 176df8a switch; ArenaToTBuilder stays the single-pass init_tiles fall-back.
make_with_new_trange rebuilt each retiled arena-ToT tile incrementally, though the source cell ranges are known up front. Use arena_outer_init so TA::retile keeps arena ToT tiles single-page.
TA_ASSERT_SINGLE_PAGE (env, off by default) makes arena_outer_init and ArenaToTBuilder::finish check Arena::page_count() <= 1, throw a TiledArray::Exception on a multi-page tile, and print a checked/violations summary at exit. Uses page_count() rather than classify_run so it stays valid for tiles with null or non-uniform inner cells. Zero overhead when unset.
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Summary
Route the size-determinable arena ToT construction paths through the up-front
arena_outer_initallocator instead of the incremental, multi-pageArenaToTBuilder, so every such outer tile is a single contiguous arena page.Multi-page outer tiles silently disqualify the strided-BLAS outer-contract +
inner-AXPY fast path (it reverts to per-cell AXPY).
make_nested_tile(
init_tiles_nested) andmake_with_new_trange(TA::retile) had regressed tothe multi-page builder in
176df8a2, though their range/fill callbacks arerandom-access — so the up-front allocator applies with no peak-memory penalty.
Why it matters
Fixing this at the construction layer makes the single-page guarantee universal:
all arena ToT built via these paths are single-page — not just one hand-patched
category. Downstream (e.g. MPQC CSV-CCk/PNO) every operand — amplitudes,
coefficients, energies, PNO/OSV-domain tensors — is single-page, instead of relying
on a post-hoc compaction of a single variable (which also costs an extra deep-copy
and a peak-memory spike).
ArenaToTBuilderis kept for the one genuinelysingle-pass path (
init_tiles), preserving the176df8a2optimization where itstill applies.
Companion MPQC change (expected)
This TA change covers ToT built through
init_tiles_nested/retile. MPQC alsoconstructs some operands via direct
ArenaToTBuildercalls, which need amatching conversion to
arena_outer_initto be single-page — landing separatelyin MPQC:
cc/solvers.h: the PNO Jacobi amplitude update and the coefficient/energyaccessors (
_pno_coeffs_tot,_osv_coeffs_tot,f_pno_diag,osv_energy).mbpt/pao_to_pno_mp2.ipp: the PAO→PNO contribution-slice builders.mbpt/csv.ipp: drops the now-redundantcompact_csv_coeffspost-hoc compaction(coefficients are now born single-page).
Validation
With both the TA and MPQC changes applied: new
make_nested_tile/retilesingle-page regression tests + full
tot_constructionsuite pass. Downstream MPQCCSV-CCk (C4H10) with
TA_ASSERT_SINGLE_PAGE=1: 0 violations across 490,124 ToTtiles, ~10% faster.