Re: Git very slow ?

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

On Sun, Mar 8, 2015 at 12:02 PM, Ken Moffat <zarniwhoop@ntlworld.com> wrote:
>
> The comments on git bisect were for linus'skernel tree, on a local
> disk.  2.3GB of repo, just under 57000 files.

Ugh. I hope you are talking about checked-out size.

    [torvalds@i7 linux]$ du -sh .git
   850M .git

because otherwise it sounds like that repo hasn't been repacked in forever.

To really pack things (which can slow things down for old history as
people said, but on the whole it tends to be a big win due to less
IO), do

   git repack -adf --window=200 --depth=200

and go away for a while. Oh, and make sure your machine has enough
memory and CPU to make that "for a while" not be *too* long.

You should have a few hundred files (just a few tens of files directly
after the repack) and that roughly 850MB of space for the repository
information itself.

But yeah, fully checked out and built with all the modules etc, you
would have much more.

That said, if you have something fairly that is consistently really
slow (like the "git commit" you mentioned), *before* doing the repack,
do

   strace -o ../trace-file -Ttt git commit

and we can get a much better guess about why it's so slow. Send it to
me in private email if you don't want to make it public, and I can
take a look.

> ping between them gives times of 0.25 to 0.3 seconds

.. and I *really* hope that was not seconds, but ms. Otherwise your
nfsv3 setup is going to be really really painful.

                          Linus