Prompt-path block scores in single-pass TF32 with a per-block error bound,
3xTF32 rescoring only near each query's top-k cut-off, so qsa_block_topk
returns the same cells in the same order, ties included. Off unless the
variable is set; says once where it cannot run (HIP, Metal, SYCL, layer-major
path). Adds qsa_two_pass_test, qsa_two_pass_status_test and the GPU parity
test qsa_two_pass_parity.
Ported from PR 4119 (bitaccesscomau); the log line of the per-prompt counters
is shortened without dropping a field.
l620 (sm_120, IQ3_S), greedy ids identical off vs on in every pair:
prompt 128K +1.65% (n=12), 256K +4.10% (n=8), 32K -0.14% (noise).
(cherry picked from commit bbf7c55f1351d913233250fe7869642f7c2b98a1)
bitaccesscomau
386f9959f1