From: Jeff King <peff@peff.net>
To: Uri Moszkowicz <uri@4refs.com>
Cc: git@vger.kernel.org
Subject: Re: Long clone time after "done."
Date: Thu, 8 Nov 2012 17:33:19 -0500 [thread overview]
Message-ID: <20121108223319.GA11734@sigill.intra.peff.net> (raw)
In-Reply-To: <CAMJd5ATX5Ru9Orp2t3p39q7tsNRfGjqDYGnf4-9QYNSTpQ-YuA@mail.gmail.com>
On Thu, Nov 08, 2012 at 04:16:59PM -0600, Uri Moszkowicz wrote:
> I ran "git cat-file commit some-tag" for every tag. They seem to be
> roughly uniformly distributed between 0s and 2s and about 2/3 of the
> time seems to be system. My disk is mounted over NFS so I tried on the
> local disk and it didn't make a difference.
>
> I have only one 1.97GB pack. I ran "git gc --aggressive" before.
Ah. NFS. That is almost certainly the source of the problem. Git will
aggressively mmap. I would not be surprised to find that RHEL4's NFS
implementation is not particularly fast at mmap-ing 2G files, and is
spending a bunch of time in the kernel servicing the requests.
Aside from upgrading your OS or getting off of NFS, I don't have a lot
of advice. The performance characteristics you are seeing are so
grossly off of what is normal that using git is probably going to be
painful. Your 2s cat-files should be more like .002s. I don't think
there's anything for git to fix here.
You could try building with NO_MMAP, which will emulate it with pread.
That might fare better under your NFS implementation. Or it might be
just as bad.
-Peff
next prev parent reply other threads:[~2012-11-08 22:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-23 18:30 Long clone time after "done." Uri Moszkowicz
2012-10-24 4:29 ` Nguyen Thai Ngoc Duy
2012-10-24 17:14 ` Uri Moszkowicz
2012-11-07 17:32 ` Uri Moszkowicz
2012-11-08 15:56 ` Jeff King
2012-11-08 17:20 ` Uri Moszkowicz
2012-11-08 20:33 ` Jeff King
2012-11-08 21:49 ` Uri Moszkowicz
2012-11-08 22:11 ` Jeff King
2012-11-08 22:16 ` Uri Moszkowicz
2012-11-08 22:33 ` Jeff King [this message]
2012-11-08 23:35 ` Uri Moszkowicz
2012-11-26 18:06 ` Uri Moszkowicz
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