Re: performance problem: "git commit filename"

[Linus Torvalds <torvalds@linux-foundation.org>]

On Sun, 13 Jan 2008, Junio C Hamano wrote:
> 
> I've reworked the patch, and in the kernel repository, a
> single-path commit after touching that path now calls 23k
> lstat(2).  It used to call 46k lstat(2) after your fix.

Ok, I really like what the patch does, and how it looks.

At the same time, I *really* hate how we now edit the cache entries in 
place for these kinds of things that really have nothing to do with the 
on-disk format. That's not a new thing (CE_UPDATE is the same), but it 
definitely got uglier.

So I think this patch is good, but I think it would be even better if we 
just bit the bullet and started looking at having a different in-memory 
representation from the on-disk one. Possibly not *that* much different: 
perhaps just keeping a pointer to the on-disk one along with a flags 
value.

That would be a fairly painful change, though (and quite independent from 
this particular one - apart from the fact that CE_UPTODATE is one of the 
users that could be cleaned up if we did that).

Comments?

			Linus