Every item here was measured on a real corpus before and after, not
reasoned about. Go corpus, event lane, first run -> now: 245.5 M
allocations -> 134.8 M, 190 GB cumulative -> 29.3 GB, 158 GB never
written -> 9.2 GB, 132 M churn pairs -> 35.7 M, 93 GB of allocator byte
work -> 0.84 GB. Wall clock: Go 40.7 s -> 19.3 s, linux kernel 239.6 s ->
194.6 s, and all ten LSP languages faster with none slower.
Graph output is unchanged, proven rather than assumed: per-class multiset
digests over the full kernel index (8,563,471 nodes identical, 18/20 node
classes and 18/24 edge classes byte-identical, the rest differing only in
the classes a same-binary re-run also perturbs through worker merge order).
The changes, each with its own reason:
arena an exact arena that is appended to later restarts growth at
8 KB instead of the 64 KB default — the cross-file pass adds a
few resolved calls to a compacted result, so the default block
was ~60 KB untouched per result, 0.5 GB of the Go worker peak.
cbm_arena_init_lazy defers the first block for arenas that are
usually never used at all.
scratch per-thread reuse instead of allocate-and-free per unit of
work: result_compact (8 MB kept), the cross-file pass (4 MB),
extract_defs' walk stack, and the sqlite index cells (a 1 MB
arena replacing 12.1 M malloc/free pairs on Go). Walk frames
moving into scratch is why pass_k8s now opens the keep window
explicitly: without it every YAML file opened a 512 KB scratch
on the main thread, +3 GB.
sqlite index cells are written in place — building the record and
copying it into the cell was a second allocation per entry,
16 M record buffers of pure churn on Go.
registry is_test_qn and common_prefix_len in one pass, per-bucket test
flags computed once instead of per candidate comparison, and
the reachability keys arena allocated lazily.
minhash the unique-trigram set is sized from the trigram count and
skips repeats, and LSH queries reuse one seen-set per worker
instead of allocating per query.
parallel lsp_surface rows and the k8s manifest prep now run across
workers (graph writes stay sequential and ordered), the file
node is hoisted out of register_and_link_def, and configlink
prepares dependency imports once with a length prefilter.
go_lsp one sealed stdlib registry shared by all workers, published
by CAS, instead of one per worker.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
The semantic pass kept four dense 768-float vectors resident per function
(ri/api/type/deco = 12.3 KB per func, ~9.4 GB transient on the linux kernel)
solely so candidate pairs could be cosine-scored after LSH. Replace the
resident floats with 4-bit quantized codes (~0.5 KB each, ~6x): new
src/semantic/rotsq.{h,c} — rotated scalar quantization from the RaBitQ
family of algorithms (Gao et al., SIGMOD 2024/2025), implemented from the
papers in plain C11 (no Eigen/library dependency): a deterministic
XXH3-seeded +-1 diagonal followed by a Fast Walsh-Hadamard rotation
(768 -> 1024 padded) spreads vector mass so per-vector scalar quantization
is near-optimal; the inner product is recovered from the codes with the
exact SQ expansion (one u8 integer dot + four multiplies) — a deterministic
pure function of the codes. Named rotsq, not rabitq: this is the family
core, not the papers' exact codebook construction.
Producers build each dense vector in a worker-local buffer, encode, and
discard; the int8 qvec export is unchanged. LSH signatures are computed
from DEQUANTIZED codes against hyperplanes in the rotated basis — random
hyperplanes are basis-agnostic, so no dense originals are retained and the
phase structure is untouched.
Estimator quality gated by sem_rotsq_ip_error_bounds (seeded vectors:
mean error < 1%, max < 4% of unit scale, ASan-green). Effect on output:
multi-threaded determinism preserved (xfs: two runs byte-identical);
SEMANTICALLY_RELATED edges shift once as scores move within ~1% of the
0.75 threshold (xfs: ~130 -> 203; sampled new pairs are high quality —
alloc/free, read-verify and collapse/insert families).
Suites: semantic 33 (incl. the new estimator gate), simhash 24,
pipeline 216 — zero failures.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel