Re: [PATCH] packfile: fix perf regression with many packs

Hi Jeff,

On Wed, 12 Aug 2026, Jeff King wrote:

> On Wed, Aug 12, 2026 at 12:51:30PM -0700, Junio C Hamano wrote:
> 
> > "Johannes Schindelin via GitGitGadget" <[email protected]>
> > writes:
> [...]
> but...
> 
> > > --- a/t/perf/p5303-many-packs.sh
> > > +++ b/t/perf/p5303-many-packs.sh
> > > @@ -141,4 +141,8 @@ test_perf "load 10,000 packs" '
> > >  	git rev-parse --verify "HEAD^{commit}"
> > >  '
> > >  
> > > +test_perf "abbreviate with 10,000 packs" '
> > > +	git rev-parse --short HEAD
> > > +'
> 
> ...I wonder what value this is adding. It shows the same slowdown as the
> existing test you can see in the context (and whose results I showed
> above).

I do think that there is value in adding this. It not only directly
reflects what GIT_PS1 runs, but it also exercises a subtly different path:
`--short` has to look for the unique abbreviation, whereas `--verify` can
stop as soon as it found the OID already.

Ciao,
Johannes