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From: Chris Wedgwood <cw@f00f.org>
To: "David S. Miller" <davem@redhat.com>
Cc: peter@chubb.wattle.id.au, viro@parcelfarce.linux.theplanet.co.uk,
	linux-kernel@vger.kernel.org
Subject: Re: stat very inefficient
Date: Wed, 28 Jul 2004 17:24:13 -0700	[thread overview]
Message-ID: <20040729002413.GA30647@taniwha.stupidest.org> (raw)
In-Reply-To: <20040728171414.5de8da96.davem@redhat.com>

On Wed, Jul 28, 2004 at 05:14:14PM -0700, David S. Miller wrote:

> Run "time find . -type f" on the kernel tree, both before and
> after removing the third unnecessary copy.  Many machines sit all
> day and stat files.

On an old crappy ia32 machine:

    cw@taniwha:~/wk/linux/cw-current$ time find . -noleaf | wc
      42372   42372 1549653

    real    0m0.188s
    user    0m0.042s
    sys     0m0.146s

that 0.2s to make almost 50K stat64 calls (if you strace and grep you
can see that count).

Since I have to do something with that data (ie. build a kernel) and
that's *probably* going to take many seconds, even making the stat
overhead 0 wouldn't put much of dent into the overall time.

What am I missing?


  --cw

  reply	other threads:[~2004-07-29  0:25 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <233602095@toto.iv>
2004-07-28 22:33 ` Peter Chubb
2004-07-28 22:45   ` David S. Miller
2004-07-29  0:08     ` Chris Wedgwood
2004-07-29  0:14       ` David S. Miller
2004-07-29  0:24         ` Chris Wedgwood [this message]
2004-07-29  0:29         ` viro
2004-07-29  7:26           ` Peter Chubb
2004-07-29  7:42             ` Andrew Morton
2004-07-29  8:49               ` Paul Jackson
2004-07-29  9:02                 ` Andrew Morton
2004-07-29  9:17                   ` Peter Chubb
2004-07-29  7:45             ` Ulrich Drepper
2004-07-29 11:42         ` Nigel Rantor
2004-07-29  1:07     ` Ulrich Drepper
2004-07-29  2:22       ` Paul Jackson
2004-07-29  4:10         ` Ulrich Drepper
2004-07-29  6:18           ` Paul Jackson
     [not found] <2mN94-3MP-9@gated-at.bofh.it>
2004-07-28 10:16 ` Andi Kleen
2004-07-28 15:38   ` David S. Miller
2004-07-28  3:13 David S. Miller
2004-07-28 18:07 ` viro

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