Faster match finding and decompression on Cortex-M7-class targets - #349

Draft

BrianPugh wants to merge 40 commits into

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stm32h7-optimizations

Commits on Jul 15, 2026

Add match-finder experiment knobs; measure SWAR variants on STM32H7B0

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e5d9ac0
Add first-byte-prefilter match finder, default on ARMv7E-M

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de07f4f
Speed up decompressor hot paths on non-Cortex-M0 targets

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06b159c
Update benchmark rows and docs for the M7 optimization results

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869c4cc
Move architecture-specific variants out of the main C sources

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42f257a
Document the variant-file convention in CLAUDE.md

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93a4d80
Make core C sources self-contained; drop the variant-file split

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2ca0a4d
Scope decompressor fast paths to ARMv7E-M after ESP32-S3 measurement

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98e3cc1
Centralize platform tuning in common.h; whole-function variant selection

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e8edc7f
Trim STM32H7B0 benchmark rows to default + generic fallback

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1f53884
Label benchmark rows so dash consistently means the default build

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6067c49
Make all platform optimizations explicit opt-in, mirroring TAMP_ESP32

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c3c81fc
Reject conflicting find_best_match selections at compile time

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9bdf1b6
Document why EXTEND_MATCH must stay a macro

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507b45a
Replace EXTEND_MATCH macros with a shared static inline function

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565a665
Fix stale benchmark preamble: build systems opt in, Tamp does not self-select

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a4705bc
Benchmark options column lists reproduce-flags, not default/non-default

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503129d
Re-measure RP2040 C row; fix runner DTR for pico-sdk USB-CDC

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200d702

Commits on Jul 16, 2026

Update stale RP2040 C row in BENCHMARKS.md

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f37c90c
Speed up decompressor hot loop: drop dead compare, defer output accounting

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7b1569d
Add QEMU-based embedded decompression profiler (tools/qemu-profiler)

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10cfef0
Speed up decompressor: snapshot window updates, fast decode loop

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8cf2356
Fuzz decompressor across chunk sizes and all flag configurations

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b2da57c
Replay fuzz corpora through real ARM binaries under QEMU

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ef10126
Speed up decompressor: two-token unroll, history-window mode, fixed-config flags

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ed107ca
qemu-profiler: count all decode helpers in core metric; add Cortex-M33 core

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396bc50
Re-measure RP2040 fast-loop row after two-token unroll

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c2bc596
Re-measure STM32H7B0 ARMV7EM row after unroll + history-window rounds

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83591b5
Speed up decompressor: 64-bit bit-reservoir refill (TAMP_RESERVOIR_REFILL)

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6acef73
Re-measure STM32H7B0 ARMV7EM row with reservoir refill

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54f10b3
Add code-size column to on-device benchmark table

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121fe55
Document TAMP_HISTORY_WINDOW's classic-stream scope and size lever

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0f4e203

Commits on Jul 17, 2026

Remove TAMP_HISTORY_WINDOW: speedup not worth the flash cost

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9c10ba1
Re-measure STM32H7B0 ARMV7EM row after TAMP_HISTORY_WINDOW removal

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7af92f1
Drop the two-token unroll from the reservoir fast loop: smaller AND faster on M7

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4df8b9d
Parameterize RP2040 harness tamp flags; refresh ARMV7EM profile summary

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09eb85f
RP2040 fastloop row: add TAMP_RESERVOIR_REFILL=1, hardware-verified win

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5c8eea1
Extract the fast decode loop; compile the careful body -Os (TAMP_COMPACT_CAREFUL_BODY)

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f232108
Remove TAMP_RESERVOIR_REFILL; the reservoir is the only fast-loop implementation

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9007409
Apply code-review fixes: guard gap, test coverage, dedup, tooling

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4e1763a