Re: segfault for git log --graph --no-walk --grep a

From: Jeff King <peff@peff.net>
Date: Feb 9, 2013, 01:08 UTC
Message-ID: <20130209010837.GA10616@sigill.intra.peff.net>
In-Reply-To: <20130209010524.GB5469@sigill.intra.peff.net>

On Fri, Feb 08, 2013 at 08:05:24PM -0500, Jeff King wrote:

Show 14 quoted lines

> On Fri, Feb 08, 2013 at 04:47:01PM -0800, Junio C Hamano wrote:
> 
> > > Yeah, that actually is a good point.  We should be using logmsg_reencode
> > > so that we look for strings in the user's encoding.
> > 
> > Perhaps like this.  Just like the previous one (which should be
> > discarded), this makes the function always use the temporary strbuf,
> > so doing this upfront actually loses more code than it adds ;-)
> 
> I like code simplification, but I worry a little about paying for the
> extra copy in the common case. I did a best-of-five "git rev-list
> --count --grep=foo HEAD" before and after your patch, though, and the
> difference was well within the noise. So maybe it's not worth caring
> about.

Oh, hold on, I'm incompetent. I measured the wrong build of git. Here are the timings for git.git:

  [before]
  $ best-of-five git rev-list --count --grep=foo HEAD
  Attempt 1: 0.503
  Attempt 2: 0.5
  Attempt 3: 0.501
  Attempt 4: 0.502
  Attempt 5: 0.5

  real    0m0.500s
  user    0m0.488s
  sys     0m0.008s

  [after]
  $ best-of-five git rev-list --count --grep=foo HEAD
  Attempt 1: 0.514
  Attempt 2: 0.525
  Attempt 3: 0.517
  Attempt 4: 0.523
  Attempt 5: 0.518

  real    0m0.514s
  user    0m0.480s
  sys     0m0.028s

So not huge, but measurable.

-Peff