Re: [PATCH v2] cache.h: eliminate SHA-1 deprecation warnings on OS X 10.8

From: Jeff King <peff@peff.net>
Date: May 11, 2013, 08:22 UTC
Message-ID: <20130511082203.GA953@sigill.intra.peff.net>
In-Reply-To: <CAJDDKr6QkeSk32kNhU_QuvrZSGUEokcEbN7Aq3PcOhvaA_hFgg@mail.gmail.com>

On Sat, May 11, 2013 at 12:11:05AM -0700, David Aguilar wrote:

Show 14 quoted lines

> > Does this perform better or worse than just setting
> > BLK_SHA1=YesPlease?  I'd naively think it could go either way: on one
> > hand adding another library dependency can slow down startup, and on
> > the other hand the implementation may or may not be optimized better
> > than the generic block-sha1/ implementation.
> 
> Pretty much identical.
> 
> Here are the timings (I should probably read t/perf/README and get
> better numbers):
> 
> Best of ten
> $ time git rev-list --all --objects >/dev/null
> [...]

I'm not sure that's a great test of sha1 performance. It will hash the commit and tree objects it loads during the traversal, but that time is almost certainly dwarfed by zlib inflation and by lookup_object.

Adding "--verify-objects" would sha1 the blobs, too, which might be more reasonable (or running "git fsck"). Something like "git add" on a large blob would also be a good test.

-Peff