First of all:
* yes, my VAIO has a slow 4200 rpm disc :-(
* strace -T indeed showed that lstat() was not guilty
* GIT_DEBUG_LOOKUP=1 git branch produced ugly 2200+ lines
Now to the patch,
On Wed 22.Jul'09 at 19:23:39 -0700, Linus Torvalds wrote:
> > Ooh yes. That would do it. It's going to peel and look up every single ref
> > it finds, so it's going to look up _hundreds_ of objects (all the tags,
> > all the commits they point to, etc etc). Even if it then only shows a
> > couple of branches.
> >
> > Junio, any ideas?
>
> I had one of my own.
>
> Does this fix it?
Yes!
[mafra@Pilar:linux-2.6]$ time git branch
27-stable
28-stable
29-stable
30-stable
dev-private
* master
option
sparse
stern
0.00user 0.01system 0:01.50elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (42major+757minor)pagefaults 0swaps
01.50 is not that good, but it doesn't "feel" terrible as 4 seconds.
[ It is incredible how 4 secs feels really bad while 2 is acceptable... ]
So thank you very much, Linus! A 50% improvement here!
And I am happy to have finally reported it, after quietly suffering for so long
thinking that "git is as fast as possible, so it is probably my fault".
PS: Out of curiosity, how many femtoseconds does it take in your
state-of-the-art machine? :-)
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