From: Steven Pratt <slpratt@austin.ibm.com>
To: Ray Bryant <raybry@sgi.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH/RFC] Simplified Readahead
Date: Mon, 27 Sep 2004 16:04:51 -0500 [thread overview]
Message-ID: <41588073.70102@austin.ibm.com> (raw)
In-Reply-To: <4158782B.9000509@sgi.com>
Ray Bryant wrote:
> Hi Steve,
>
> On question I have (and I'm sorry, I haven't had time to look at your
> patch to sort this out) is what happens if the user supplies a rather
> serious I/O size, will you read ahead multiples of that, or what
> happens? Or, for that matter, how well will it perform?
Same behavior as the old code. I/Os are broken up into at most
max_readahead size pieces. In the case of the old code only 1 of these
could be outstanding. In the new code there could be at most 2
outstanding at any point in time.
>
> I've heard about HPC applications for IRIX that issue a 2GB read. :-)
This is why for these types of applications, especially on RAID arrays,
you need to set max_readahead into the MBs. (But that is a different topic).
Steve
next prev parent reply other threads:[~2004-09-27 21:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-23 16:06 [PATCH/RFC] Simplified Readahead Steven Pratt
2004-09-23 22:14 ` Joel Schopp
2004-09-24 0:21 ` Nick Piggin
2004-09-24 2:42 ` Andrew Morton
2004-09-24 15:40 ` Steven Pratt
2004-09-24 16:16 ` Nick Piggin
2004-09-24 16:48 ` Steven Pratt
2004-09-24 22:05 ` Andrew Morton
2004-09-24 22:43 ` Steven Pratt
2004-09-24 23:01 ` Andrew Morton
2004-09-27 15:39 ` Steven Pratt
2004-09-27 19:26 ` Andrew Morton
2004-09-28 10:13 ` Jens Axboe
2004-09-24 22:55 ` Steven Pratt
2004-09-27 20:29 ` Ray Bryant
2004-09-27 21:04 ` Steven Pratt [this message]
2004-09-25 0:45 ` Nick Piggin
2004-09-25 1:01 ` Ram Pai
2004-09-25 6:07 ` Ram Pai
2004-09-27 15:30 ` Steven Pratt
2004-09-27 18:42 ` Ram Pai
2004-09-27 20:07 ` Steven Pratt
2004-09-29 18:46 ` Ram Pai
2004-09-29 22:33 ` Steven Pratt
2004-09-29 23:13 ` Andreas Dilger
2004-09-30 2:26 ` Ram Pai
2004-09-30 5:29 ` Andrew Morton
2004-09-30 20:20 ` Stephen C. Tweedie
2004-09-30 1:12 ` Ram Pai
2004-10-01 21:02 ` Steven Pratt
2004-10-05 17:52 ` Ram Pai
[not found] <372479081@toto.iv>
2004-09-24 5:00 ` Peter Chubb
2004-09-24 22:57 ` Steven Pratt
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