From: Jon Burgess <lkml@jburgess.uklinux.net>
To: Andrew Morton <akpm@osdl.org>
Cc: Jon Burgess <lkml@jburgess.uklinux.net>, linux-kernel@vger.kernel.org
Subject: Re: ext2/3 performance regression in 2.6 vs 2.4 for small interleaved writes
Date: Sat, 14 Feb 2004 15:00:27 +0000 [thread overview]
Message-ID: <402E380B.8070806@jburgess.uklinux.net> (raw)
In-Reply-To: <20040212015626.48631555.akpm@osdl.org>
Andrew Morton wrote:
>So you'll see that instead of a single full-bandwidth
>write, we do two half-bandwidth writes. If it weren't for disk writeback
>caching, it would be as much as 4x slower.
>
Write caching does indeed make a big difference. Here is a test run on a
drive with and without write caching (hdparm -W 0/1). The test was done
on 2.6.2 with ext3 and shows the write speed in MB/s:
Write Cache 1 Stream 2 Streams
Enabled 21.54 3.66
Disabled 18.11 0.46
The two stream case is almost 10x slower without write caching.
I don't think this explains the difference between 2.4 and 2.6 unless
one of them changes the write cache mode of the drive.
Jon
prev parent reply other threads:[~2004-02-14 15:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-11 19:04 ext2/3 performance regression in 2.6 vs 2.4 for small interleaved writes Jon Burgess
2004-02-11 20:28 ` Rik van Riel
2004-02-11 21:02 ` Michael Frank
2004-02-11 21:18 ` Diego Calleja
2004-02-12 2:00 ` Dave Olien
2004-02-12 2:23 ` Andrea Arcangeli
2004-02-12 9:42 ` ext2/3 performance regression in 2.6 vs 2.4 for small interl Giuliano Pochini
2004-02-12 10:15 ` John Bradford
2004-02-12 10:27 ` Nick Piggin
2004-02-12 17:05 ` Michael Frank
2004-02-12 17:18 ` Valdis.Kletnieks
2004-02-12 20:55 ` Helge Hafting
2004-02-13 1:57 ` Jamie Lokier
2004-02-13 2:05 ` Nick Piggin
2004-02-12 14:59 ` Andrea Arcangeli
2004-02-13 12:15 ` ext2/3 performance regression in 2.6 vs 2.4 for small interleaved writes Jon Burgess
2004-02-12 10:40 ` Jon Burgess
2004-02-12 20:17 ` Hans Reiser
2004-02-12 9:56 ` Andrew Morton
2004-02-12 20:20 ` Jon Burgess
2004-02-13 8:28 ` Juan Piernas Canovas
2004-02-16 17:51 ` Alex Zarochentsev
2004-02-16 20:03 ` Jon Burgess
2004-02-13 12:35 ` Jon Burgess
2004-02-14 15:00 ` Jon Burgess [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=402E380B.8070806@jburgess.uklinux.net \
--to=lkml@jburgess.uklinux.net \
--cc=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.