From: Ulrich Drepper <drepper@redhat.com>
To: Peter Chubb <peter@chubb.wattle.id.au>
Cc: viro@parcelfarce.linux.theplanet.co.uk,
"David S. Miller" <davem@redhat.com>,
Chris Wedgwood <cw@f00f.org>,
linux-kernel@vger.kernel.org
Subject: Re: stat very inefficient
Date: Thu, 29 Jul 2004 00:45:30 -0700 [thread overview]
Message-ID: <4108AB1A.1050706@redhat.com> (raw)
In-Reply-To: <16648.42669.907048.112765@wombat.chubb.wattle.id.au>
Peter Chubb wrote:
> With hot cache the system time is really small.
But this is not all you'll have to look at.
Single application performs does not really tell the whole story. If
you touch more memory, more cache is used. In SMP machines the cost of
cacheline transfers are added. And in multi-core processors the cores
even share some cache which means every bit used might decrease system
performance ever so slightly.
If the added complexity is manageable the avoided memory operations
should be a win even if you cannot directly measure it.
--
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
next prev parent reply other threads:[~2004-07-29 7:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <233602095@toto.iv>
2004-07-28 22:33 ` stat very inefficient 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
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 [this message]
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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