From: Andrew Morton <akpm@osdl.org>
To: Doug Ledford <dledford@redhat.com>
Cc: antlarr@tedial.com, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org
Subject: Re: iowait problems on 2.6, not on 2.4
Date: Sat, 29 May 2004 21:52:26 -0700 [thread overview]
Message-ID: <20040529215226.68605319.akpm@osdl.org> (raw)
In-Reply-To: <1085877991.18642.336.camel@compaq.xsintricity.com>
Doug Ledford <dledford@redhat.com> wrote:
>
> But, I could be wrong. Give it a try and see what happens. In the 2.4
> kernels I would tell you to tweak /proc/sys/vm/{min,max}-readahead,
> don't know if those two knobs still exist in 2.6 and if they have the
> same effect. Andrew?
blockdev --setra N /dev/sda (N is in 512 byte units)
echo N > /sys/block/sda/queue/read_ahead_kb (N is in kilobytes)
Also there was breakage (recently fixed) in which /dev/sdaN's readahead
setting was being inherited from the blockdev on which /dev resides. But
reading regular files is OK.
next prev parent reply other threads:[~2004-05-30 4:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200405261743.28111.antlarr@tedial.com>
[not found] ` <20040526205225.7a0866aa.akpm@osdl.org>
[not found] ` <200405281516.41901.antlarr@tedial.com>
2004-05-28 22:45 ` iowait problems on 2.6, not on 2.4 Andrew Morton
2004-05-30 0:46 ` Doug Ledford
2004-05-30 4:52 ` Andrew Morton [this message]
2004-05-31 11:24 ` Antonio Larrosa Jiménez
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