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[Instructions -5.25% vs main; paired PGO estimate] Carry unused green query values as their existing bytes - #122

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[Instructions -5.25% vs main; paired PGO estimate] Carry unused green query values as their existing bytes#122
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@xmakro xmakro commented Sep 7, 2026

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Carry the prior query-data prefix and its source-file, allocation and hygiene tables, preserving offsets and verifying the full 128-bit key fingerprint. Already-carried green values avoid decoding and re-encoding. A distinct private cache version and an eight-generation Unix-only bound protect the format and mapping lifecycle.

Comparison Wall time Instructions Peak RSS
Complete PR vs main -4.078% -5.247% -1.502%
Profile, complete PR vs main Wall time
check -3.349%
debug -5.208%
opt -3.667%

Negative percentages mean less elapsed time or fewer resources. The title is an individual local instruction-count estimate: instructions:u as an equal-case geometric mean over the 249 Primary cases, the metric the upstream perf bot summarizes; small changes may be measurement noise.

The two recorded repetitions give aggregate instruction estimates of -5.247% and -5.247% for the title comparison. Mixed directions are marked in the title. This repeatability check is not a confidence interval.

Both compilers use the same source base, CI LLVM, fixed standard libraries, ThinLTO and jemalloc. Each has separate nine-workload Rust PGO training. The stock collector measures all 20 Primary benchmarks: 249 Check/Debug/Opt and full/incremental cases, two observations per compiler per case, alternating baseline/candidate order by crate. No other campaign builds run during measurement. Percentages are equal-case geometric means. LLVM retraining and BOLT are omitted.

This branch has one commit directly on main. Its exact measured source passed the full UI and incremental suites plus the additional suites recorded in the build provenance.

Fixed main commit: da47efd27287edb02eed0b5a178a165c8f258e37. Measured source patch SHA-256: 8bc66c80b75624b78b8ffbb280ba180fc5f983d7fe272e61b05c21d22ca1e871.

Local raw measurements and per-case CSVs: independent-pr122-main-v1-comparison.csv in the September 6 investigation directory. Build/test provenance: pgo/independent-pr122-source-timing-v1/provenance.json.

@xmakro xmakro changed the title [3.671% fewer Check instructions] Carry unused green query values as their existing bytes [Check instructions -3.671%; isolated pre-PGO screen] Carry unused green query values as their existing bytes Sep 8, 2026
@xmakro
xmakro force-pushed the perf-review-20260907/08-count-captured-tokens branch from 922c083 to b663e22 Compare September 9, 2026 06:21
@xmakro
xmakro force-pushed the perf-review-20260907/09-carry-query-bytes branch from f9ae497 to 41bd039 Compare September 9, 2026 06:21
@xmakro xmakro changed the title [Check instructions -3.671%; isolated pre-PGO screen] Carry unused green query values as their existing bytes [Wall time -4.08% vs main; paired PGO estimate] Carry unused green query values as their existing bytes Sep 9, 2026
@xmakro
xmakro changed the base branch from perf-review-20260907/08-count-captured-tokens to main September 9, 2026 06:21
@xmakro
xmakro force-pushed the perf-review-20260907/09-carry-query-bytes branch from 41bd039 to a88b5e8 Compare September 13, 2026 04:01
@xmakro
xmakro changed the base branch from main to perf-review-20260907/00-base September 13, 2026 04:22
@xmakro
xmakro changed the base branch from perf-review-20260907/00-base to main September 13, 2026 04:22
@xmakro xmakro changed the title [Wall time -4.08% vs main; paired PGO estimate] Carry unused green query values as their existing bytes [Instructions -5.25% vs main; paired PGO estimate] Carry unused green query values as their existing bytes Sep 13, 2026
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