The device correction-surface fit (gpu-tail2) keeps its per-term arrays - the
terms, their parity, the group CSR, the three subsets' orders and the per-term
weights, about 60 bytes a term - as engine members, and nothing freed them
after the last surface. They stayed on the card through the merge, where the
GPU Wilson outlier test (gpu-tail) then asks for ~96 bytes per full. On a
large rotation set (139.8 M partials, 13.35 M fulls, 16 GB card) the engine's
resident arrays left 1242 MiB free for the first Wilson test and 998 MiB for
the one after the automatic resolution cut, against 1222 MiB needed: the run
stopped with "Wilson outlier test ... run the CPU build" although nothing ran
beside it. The surfaces' buffers are released once the last surface is
fitted (the next pass's surfaces build their own), which gives back 905 MiB
there.
The up-front checks of the three dataset-sized tail steps (Wilson test, pair
sort, error-model fit) also read free memory as cudaMemGetInfo reports it,
which counts what the allocation pool holds with no buffer in it as taken.
They now hand that back and, only if it is still short, wait for GPU work
running beside the merge (GPUWorkBeside, the speculative probe) to end before
giving up - as the engine's own allocations already do. That changes when a
step runs, never what it computes; a set that does not fit still fails at
once with the same "run the CPU build" message.
p.mtz: the large set completes (and is identical with the Wilson test forced
onto the host); myob 9bdd6916 and 8a1a 309ea9a8 unchanged.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SVmAWnzCmRKAXVUCdc4iNi
leonarski_fandClaude Opus 5.5
4be71702ec