perf(gix-hash): upgrade sha1dc to 0.1.2 - #3012
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sha1dc 0.1.2 speeds up the collision check: recompression now uses the SHA-1 hardware instructions where available, and the filter for known disturbance vectors got cheaper. The minimum version is raised so dependents of `gix-hash` pick it up too. Performance: On an Apple M4 (4P/6E), against a bare clone of `git/git`: 421,363 objects, 305 MiB pack. Built from the tree of GitoxideLabs#3008 with the `max-pure` feature set and one target directory, with only the SHA-1 backend toggled; fastest of 5 rounds, rotating between builds each round. | operation | `sha1-checked` | `sha1dc` 0.1.1 | `sha1dc` 0.1.2 | vs 0.1.1 | |---|---:|---:|---:|---:| | `gix free pack verify` (1 thread) | 12.85s | 6.11s | 5.65s | **1.08x** | | `gix free pack index create` (1 thread) | 14.69s | 7.77s | 7.30s | **1.06x** | | `gix free pack verify` (all cores) | 2.28s | 1.06s | 1.03s | 1.03x | | `gix free pack index create` (all cores) | 4.28s | 2.80s | 2.69s | 1.04x | The all-cores runs were noisy on this machine, and their medians are on par between 0.1.1 and 0.1.2; the single-threaded gains are consistent across rounds. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Sebastian Thiel (Byron)
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Sep 23, 2026
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sha1dc 0.1.2 speeds up the collision check: recompression now uses the SHA-1 hardware instructions where available, and the filter for known disturbance vectors got cheaper. The minimum version is raised so dependents of
gix-hashpick it up too.Performance: On an Apple M4 (4P/6E), against a bare clone of
git/git: 421,363 objects, 305 MiB pack. Built from the tree of #3008 with themax-purefeature set and one target directory, with only the SHA-1 backend toggled; fastest of 5 rounds, rotating between builds each round.sha1-checkedsha1dc0.1.1sha1dc0.1.2gix free pack verify(1 thread)gix free pack index create(1 thread)gix free pack verify(all cores)gix free pack index create(all cores)The all-cores runs were noisy on this machine, and their medians are on par between 0.1.1 and 0.1.2; the single-threaded gains are consistent across rounds.