From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 17 Jun 2014 18:03:46 GMT
Subject: Re: [PATCH v10 1/1] refs.c: SSE2 optimizations for check_refname_component
Message-ID: <xmqq8uovmn0d.fsf@gitster.dls.corp.google.com>
In-Reply-To: <1403025199-21360-2-git-send-email-dturner@twitter.com>

David Turner <dturner@twopensource.com> writes:

> Optimize check_refname_component using SSE2 on x86_64.
>
> git rev-parse HEAD is a good test-case for this, since it does almost
> nothing except parse refs.  For one particular repo with about 60k
> refs, almost all packed, the timings are:
>
> Look up table: 29 ms
> SSE2:          23 ms
>
> This cuts about 20% off of the runtime.
>
> Ondřej Bílka <neleai@seznam.cz> suggested an SSE2 approach to the
> substring searches, which netted a speed boost over the SSE4.2 code I
> had initially written.
>
> Signed-off-by: David Turner <dturner@twitter.com>
> ---

When applied on top of your dde8a902 (refs.c: optimize
check_refname_component(), 2014-06-03), this seems to fail t1402 for
me.

Test Summary Report
-------------------
t1402-check-ref-format.sh (Wstat: 256 Tests: 93 Failed: 9)
  Failed tests:  28, 36, 38, 40, 63, 75, 77, 85-86
  Non-zero exit status: 1

#28 is the one that runs "check-ref-format heads/v@{ation".