From: Anton Blanchard <anton@samba.org>
To: "David S. Miller" <davem@redhat.com>
Cc: ak@suse.de, mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: speed difference between using hard-linked and modular drives?
Date: Sat, 10 Nov 2001 16:20:06 +1100 [thread overview]
Message-ID: <20011110162006.C767@krispykreme> (raw)
In-Reply-To: <20011109064540.A13498@wotan.suse.de> <20011108.220444.95062095.davem@redhat.com> <20011109073946.A19373@wotan.suse.de> <20011108.231632.18311891.davem@redhat.com>
In-Reply-To: <20011108.231632.18311891.davem@redhat.com>
Hi,
> It _IS_ a big deal. Fetching _ONE_ hash chain cache line
> is always going to be cheaper than fetching _FIVE_ to _TEN_
> page struct cache lines while walking the list.
Exactly, the reason I found the pagecache hash was too small was because
__find_page_nolock was one of the worst offenders when doing zero copy
web serving of a large dataset.
> Even if prefetch would kill all of this overhead (sorry, it won't), it
> is _DUMB_ and _STUPID_ to bring those _FIVE_ to _TEN_ cache lines into
> the processor just to lookup _ONE_ page.
Yes you cant expect prefetch to help you when you use the data 10
instructions after you issue the prefetch. (ie walking the hash chain)
Anton
next prev parent reply other threads:[~2001-11-10 5:24 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.LNX.4.33.0111081802380.15975-100000@localhost.localdomain.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.33.0111081836080.15975-100000@localhost.localdomain.suse.lists.linux.kernel>
2001-11-08 23:00 ` speed difference between using hard-linked and modular drives? Andi Kleen
2001-11-09 0:05 ` Anton Blanchard
2001-11-09 5:45 ` Andi Kleen
2001-11-09 6:04 ` David S. Miller
2001-11-09 6:39 ` Andi Kleen
2001-11-09 6:54 ` Andrew Morton
2001-11-09 7:17 ` David S. Miller
2001-11-09 7:16 ` Andrew Morton
2001-11-09 7:24 ` David S. Miller
2001-11-09 8:21 ` Ingo Molnar
2001-11-09 7:35 ` Andrew Morton
2001-11-09 7:44 ` David S. Miller
2001-11-09 7:14 ` David S. Miller
2001-11-09 7:16 ` David S. Miller
2001-11-09 12:59 ` Alan Cox
2001-11-09 12:54 ` David S. Miller
2001-11-09 13:15 ` Philip Dodd
2001-11-09 13:26 ` David S. Miller
2001-11-09 20:45 ` Mike Fedyk
2001-11-09 13:17 ` Andi Kleen
2001-11-09 13:25 ` David S. Miller
2001-11-09 13:39 ` Andi Kleen
2001-11-09 13:41 ` David S. Miller
2001-11-10 5:20 ` Anton Blanchard [this message]
2001-11-10 4:56 ` Anton Blanchard
2001-11-10 5:09 ` Andi Kleen
2001-11-10 13:29 ` David S. Miller
2001-11-10 13:44 ` David S. Miller
2001-11-10 13:52 ` David S. Miller
2001-11-10 14:29 ` Numbers: ext2/ext3/reiser Performance (ext3 is slow) Oktay Akbal
2001-11-10 14:47 ` arjan
2001-11-10 17:41 ` Oktay Akbal
2001-11-10 17:56 ` Arjan van de Ven
2001-11-15 17:24 ` Stephen C. Tweedie
2001-11-12 16:59 ` [patch] arbitrary size memory allocator, memarea-2.4.15-D6 Ingo Molnar
2001-11-12 18:19 ` Jeff Garzik
2001-11-12 23:26 ` Ingo Molnar
2001-11-13 15:59 ` Riley Williams
2001-11-14 20:49 ` Tom Gall
2001-11-15 1:11 ` Anton Blanchard
2001-11-17 18:00 ` Eric W. Biederman
2001-11-09 3:12 ` speed difference between using hard-linked and modular drives? Rusty Russell
2001-11-09 5:59 ` Andi Kleen
2001-11-09 11:16 ` Helge Hafting
2001-11-12 9:59 ` Rusty Russell
2001-11-12 23:23 ` David S. Miller
2001-11-12 23:14 ` Rusty Russell
2001-11-13 1:30 ` Mike Fedyk
2001-11-13 1:15 ` David Lang
2001-11-08 16:01 Roy Sigurd Karlsbakk
2001-11-08 17:02 ` Ingo Molnar
2001-11-08 17:37 ` Ingo Molnar
2001-11-08 23:59 ` Anton Blanchard
2001-11-09 5:11 ` Keith Owens
2001-11-10 3:35 ` Anton Blanchard
2001-11-10 7:26 ` Keith Owens
2001-11-08 17:53 ` Robert Love
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