Re: git-fetch per-repository speed issues

[Junio C Hamano <junkio@cox.net>]

Linus Torvalds <torvalds@osdl.org> writes:

> Ok, a "git fetch" really shouldn't take any longer than a single 
> connection. However, the fact that you have 32 heads, and it takes pretty 
> close to _exactly_ 32 times 0.410 seconds (32*0.410s = 13.1s) makes me 
> suspect that "git fetch" is just broken and fetches one branch at a time. 
>
> Which would be just stupid.
>
> But look as I might, I see only that one "git-fetch-pack" in git-fetch.sh 
> that should trigger. Once. Not 32 times. But your timings sure sound like 
> it's doing a _lot_ more than it should.
>
> Junio, any ideas?

Isn't that because the repository have 32 subprojects, totally
unrelated content-wise?  If you have real stuff to pull from
there your pack generation needs to do 32 time as much work as
you would for a single head in that case.

If you are discussing "peek-remote runs, find out the 32 heads
are all up to date and no pack is generated" case, then you are
right.  There is one single fetch-pack to grab the specified
heads, and after that, an optional single ls-remote and
fetch-pack runs only once to follow all new tags.