From: Johannes Schindelin via GitGitGadget Date: Mon, 28 Sep 2026 15:51:27 GMT Subject: [PATCH 0/4] Add a compile-time option to use the new, very fast sha1dc Rust crate Message-ID: I stumbled across this new Rust crate last week. Its performance numbers are quite impressive. Naturally, I want to make use of this and get for Windows, which is used on many monorepos where this makes a real difference: In a pretty fast and loose test, I verified that a git index-pack runs roughly three times faster solely due to using those SIMD-based optimizations! As a safety precaution, because this sha1dc crate is quite new, I wanted to introduce an escape hatch: core.sha1dcBackend=c, but turn it on by default, which is the reason for the three additional patches. Should these patches be undesirable for the Git project? I would not be mad at all if they were simply dropped. Johannes Schindelin (4): libgitcore: add `sha1dc` as an optional feature sha1dc: allow selecting the C backend without rebuilding pthread: provide `pthread_once()` shims for Windows and for NO_PTHREADS sha1dc: make `sha1dc_init()` thread-safe Cargo.toml | 4 ++ Documentation/config/core.adoc | 5 ++ Makefile | 29 +++++++++ compat/win32/pthread.c | 16 +++++ compat/win32/pthread.h | 5 ++ hash.h | 5 ++ sha1dc_git.c | 109 +++++++++++++++++++++++++++++++-- sha1dc_git.h | 5 +- sha1dc_rs.h | 37 +++++++++++ src/lib.rs | 2 + src/sha1dc_rs.rs | 78 +++++++++++++++++++++++ t/helper/test-sha1.c | 19 +++++- t/t0013-sha1dc.sh | 21 ++++++- thread-utils.h | 16 +++++ 14 files changed, 343 insertions(+), 8 deletions(-) create mode 100644 sha1dc_rs.h create mode 100644 src/sha1dc_rs.rs base-commit: 3bc0341126508f78f5869cbfc0005e987efdf0c7 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2240%2Fdscho%2Foptionally-use-sha1dc-rs-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2240/dscho/optionally-use-sha1dc-rs-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/2240 -- gitgitgadget