RE:

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

On Thu, 7 May 2009, Bevan Watkiss wrote:
> 
> Basically I have a copy of my tree where only git can write to it, so I know
> the files are right.  The NAS box I have the tree on is slow, so reading the
> tree adds about 10 minutes to the process when I only want to update a few
> files.

Ouch.

You could try doing

	[core]
		preloadindex = true

and see if that helps some of your loads. It does limit even the parallel 
tree stat to 20 or so, but if most of your cost is in just doing the 
lstat() over the files to see that they haven't changed, you might be 
getting a factor-of-20 speedup for at least _some_ of what you do.

If you can, it might also be interesting to see system call trace patterns 
(with times!) to see if there is something obviously horribly bad going 
on. If you're running under Linux, and don't think the data contains 
anything very private, send me the output of "strace -f -T" of the most 
problematic operations, and maybe I can see if I can come up with anything 
interesting.

I have long refused to use networked filesystems because I used to find 
them -so- painful when working with CVS, so none of my performance work 
has ever really directly concentrated on long-latency filesystems. Even 
the index preload was all done "blind" with other people reporting issues 
(and happily I could see some of the effects with local filesystems and 
multiple CPU's ;).

			Linus