On Tue, Jan 15, 2013 at 5:38 AM, Ross Lagerwall <rosslagerw...@gmail.com> wrote: > Hi, > > I have noticed a performance regression in git grep between v1.8.1 and > v1.8.1.1: > > On the kernel tree: > For git 1.8.1: > $ time git grep foodsgsg > > real 0m0.158s > user 0m0.290s > sys 0m0.207s > > For git 1.8.1.1: > $ time /tmp/g/bin/git grep foodsgsg > > real 0m0.501s > user 0m0.707s > sys 0m0.493s
Interesting. I see the regression on linux-2.6 too (0.6s real vs 0.9s). > A bisect seems to indicate that it was introduced by 94bc67: > commit 94bc671a1f2e8610de475c2494d2763355a99f65 > Author: Jean-Noël AVILA <avila...@gmail.com> > Date: Sat Dec 8 21:04:39 2012 +0100 > > Add directory pattern matching to attributes > > The manpage of gitattributes says: "The rules how the pattern > matches paths are the same as in .gitignore files" and the gitignore > pattern matching has a pattern ending with / for directory matching. > > This rule is specifically relevant for the 'export-ignore' rule used > for git archive. Not the real contributor to the regression, but it should be noted that glibc's strrchr does not employ a typical loop. Instead it advances with strchr with a note that strchr is much faster. It looks like strchr compares a word at a time instead of a byte. We might want to do the same. I don't have time to look into details now, but by enabling DEBUG_ATTR, it looks like this commit makes it push and pop patterns a lot more than without the commit. -- Duy -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
