Re: [PATCH 0/4] Add a compile-time option to use the new, very fast sha1dc Rust crate
- From
Johannes Schindelin <johannes.schindelin@gmx.de>
- Date
- Sep 28, 2026, 16:20 UTC
- Message-ID
- <2f7509d7-1166-1303-87b4-58974702c73d@gmx.de>
- In-Reply-To
- <pull.2240.git.1790610691.gitgitgadget@gmail.com>
Hi,
On Mon, 28 Sep 2026, Johannes Schindelin via GitGitGadget wrote:
> 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,
^^^^^^^^^^^^^^^^^^^ in Git for Windows
My sincerest apologies; I am using Cohere Transcribe to compensate for my inadequate typing speed, which typically works very, very well for me, yet missed this typo. Likewise:
Show 8 quoted lines
> 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
^ , and
Sorry about that, Johannes
Show 35 quoted lines
> 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 >