Re: [PATCH 3/4] diffcore-pickaxe: further refactor count_match()
René Scharfe <rene.scharfe@lsrfire.ath.cx> writes:
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> I get this (Ubuntu 8.10 x64, Fedora 10 x64 using the same Linux repo,
> Windows Vista x64 using a different Linux repo with the same HEAD on
> NTFS and msysgit, numbers are the elapsed time in seconds, best of five
> runs):
>
> Ubuntu Fedora Windows
> v1.6.2-rc2 8.14 8.16 9.236
> v1.6.2-rc2+[1-4] 2.43 2.45 2.995
> v1.6.2-rc2+[1-4]+memmem 1.31 1.25 2.917
> v1.6.2-rc2+[1-3]+memmem 1.51 1.16 8.455
>
> Ubuntu has glibc 2.8, while Fedora 10 has glibc 2.9, with a new and more
> efficient memmem() implementation. On Windows, we use our own naive
> memmem() implementation.
Yeah, what does glibc use these days? Some variant of Boyer-Moore?
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> So using memmem() is worthwhile. And providing a better fall-back
> version in compat/ can speed up this particular case to the point where
> the fourth patch becomes moot.
>
> Hmm, gnulib (http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=summary)
> contains all parts ready for copy & paste, licensed under the GPL 2 or
> up. That won't cause problems with the libgit2 relicensing effort, as
> memmem() won't end up in there, right?
Junio C Hamano <gitster@pobox.com>