From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 21 Jul 2025 18:33:52 GMT
Subject: Re: [PATCH 0/7] RFC: Accelerate xdiff and begin its rustification
Message-ID: <xmqq4iv5z94f.fsf@gitster.g>
In-Reply-To: <45ea5d1d-05dd-4f7a-bee5-ea3936d23d0a@gmail.com>

Phillip Wood <phillip.wood123@gmail.com> writes:

> ... by 15%. Just over half of that seems to come from hoisting the
> check for whitespace flags in xdl_hash_record() out of the loop
> in xdl_prepare_ctx() and the rest comes from the change in hash
> function.

The first half of that alone is interesting enough ;-).

> As I understand it the hash is implemented using SIMD
> compiler intrinsics and the rust implementation is basically a
> copy of the C code in libxxhash. I wonder how well xxhash performs
> compared to our existing hash on platforms without an optimized
> implementation.

Yeah, that indeed is worth investigating.

Thanks.