From: Wu Fengguang <wfg@mail.ustc.edu.cn>
To: Jens Axboe <axboe@suse.de>
Cc: linux-kernel@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>,
Andrew Morton <akpm@osdl.org>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Badari Pulavarty <pbadari@us.ibm.com>
Subject: Re: [RFC] kernel facilities for cache prefetching
Date: Tue, 2 May 2006 16:20:10 +0800 [thread overview]
Message-ID: <346557995.03234@ustc.edu.cn> (raw)
Message-ID: <20060502082009.GA9038@mail.ustc.edu.cn> (raw)
In-Reply-To: <20060502080935.GS3814@suse.de>
On Tue, May 02, 2006 at 10:09:36AM +0200, Jens Axboe wrote:
> I tried something very similar to this years ago, except I made it
> explicit instead of hiding it in the blk_run_backing_dev() which we
> didn't have at that time. My initial results showed that you would get a
> load of requests for different pages so would end up doing io randomly
> instead again.
Yes, the hard one would be _not_ to impact normal I/Os in any way.
A simple solution for the case of deadline scheduler would be:
- static const int read_expire = HZ / 2; /* max time before a read is submitted. */
+ static const int read_expire = HZ / 2; /* max time before a impending read is submitted. */
+ static const int reada_expire = HZ * 30; /* max time before a read-ahead is submitted. */
Wu
next prev parent reply other threads:[~2006-05-02 8:19 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20060502075049.GA5000@mail.ustc.edu.cn>
2006-05-02 7:50 ` [RFC] kernel facilities for cache prefetching Wu Fengguang
2006-05-02 12:46 ` Diego Calleja
[not found] ` <20060502144203.GA10594@mail.ustc.edu.cn>
2006-05-02 14:42 ` Wu Fengguang
2006-05-02 16:07 ` Diego Calleja
[not found] ` <20060503064503.GA4781@mail.ustc.edu.cn>
2006-05-03 6:45 ` Wu Fengguang
2006-05-03 18:14 ` Diego Calleja
2006-05-03 23:39 ` Zan Lynx
2006-05-04 1:37 ` Diego Calleja
2006-05-02 15:55 ` Linus Torvalds
2006-05-02 16:35 ` Andi Kleen
[not found] ` <20060503041106.GC5915@mail.ustc.edu.cn>
2006-05-03 4:11 ` Wu Fengguang
2006-05-03 17:28 ` Badari Pulavarty
[not found] ` <346733486.30800@ustc.edu.cn>
2006-05-04 15:03 ` Linus Torvalds
2006-05-04 16:57 ` Badari Pulavarty
[not found] ` <20060505144451.GA6134@mail.ustc.edu.cn>
2006-05-05 14:44 ` Wu Fengguang
[not found] ` <20060503071325.GC4781@mail.ustc.edu.cn>
2006-05-03 7:13 ` Wu Fengguang
2006-05-03 12:59 ` Nikita Danilov
2006-05-03 22:20 ` Rik van Riel
[not found] ` <20060506011125.GA9099@mail.ustc.edu.cn>
2006-05-06 1:11 ` Wu Fengguang
2006-05-04 0:28 ` Linda Walsh
2006-05-04 1:31 ` Linus Torvalds
2006-05-04 7:08 ` Ph. Marek
2006-05-04 7:33 ` Arjan van de Ven
[not found] ` <20060504121454.GB6008@mail.ustc.edu.cn>
2006-05-04 12:14 ` Wu Fengguang
2006-05-04 12:34 ` Arjan van de Ven
2006-05-03 21:45 ` Linda Walsh
[not found] ` <20060504121212.GA6008@mail.ustc.edu.cn>
2006-05-04 12:12 ` Wu Fengguang
2006-05-04 18:57 ` Linda Walsh
[not found] ` <20060505152007.GB6134@mail.ustc.edu.cn>
2006-05-05 15:20 ` Wu Fengguang
2006-05-04 9:02 ` Helge Hafting
2006-05-02 7:58 ` Arjan van de Ven
[not found] ` <20060502080619.GA5406@mail.ustc.edu.cn>
2006-05-02 8:06 ` Wu Fengguang
2006-05-02 8:30 ` Arjan van de Ven
[not found] ` <20060502085325.GA9190@mail.ustc.edu.cn>
2006-05-02 8:53 ` Wu Fengguang
2006-05-06 6:49 ` Denis Vlasenko
2006-05-02 8:55 ` Arjan van de Ven
2006-05-02 11:39 ` Jan Engelhardt
[not found] ` <20060502114853.GA9983@mail.ustc.edu.cn>
2006-05-02 11:48 ` Wu Fengguang
2006-05-02 22:03 ` Dave Jones
2006-05-02 8:09 ` Jens Axboe
[not found] ` <20060502082009.GA9038@mail.ustc.edu.cn>
2006-05-02 8:20 ` Wu Fengguang [this message]
2006-05-03 22:05 ` Benjamin LaHaise
2006-05-02 19:10 ` Pavel Machek
2006-05-02 23:36 ` Nigel Cunningham
[not found] ` <20060503023505.GB5915@mail.ustc.edu.cn>
2006-05-03 2:35 ` Wu Fengguang
[not found] ` <20060503023223.GA5915@mail.ustc.edu.cn>
2006-05-03 2:32 ` Wu Fengguang
[not found] ` <20060503071948.GD4781@mail.ustc.edu.cn>
2006-05-03 7:19 ` Wu Fengguang
[not found] ` <20060504122830.GA6205@mail.ustc.edu.cn>
2006-05-04 12:28 ` Wu Fengguang
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