From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Wu Fengguang <wfg@mail.ustc.edu.cn>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 12/33] readahead: min/max sizes
Date: Thu, 25 May 2006 14:50:59 +1000 [thread overview]
Message-ID: <447537B3.7050707@yahoo.com.au> (raw)
In-Reply-To: <348469541.17438@ustc.edu.cn>
Wu Fengguang wrote:
>- Enlarge VM_MAX_READAHEAD to 1024 if new read-ahead code is compiled in.
> This value is no longer tightly coupled with the thrashing problem,
> therefore constrained by it. The adaptive read-ahead logic merely takes
> it as an upper bound, and will not stick to it under memory pressure.
>
I guess this size enlargement is one of the main reasons your
patchset improves performance in some cases.
There is currently some sort of thrashing protection in there.
Obviously you've found it to be unable to cope with some situations
and introduced a lot of really fancy stuff to fix it. Are these just
academic access patterns, or do you have real test cases that
demonstrate this failure (ie. can we try to incrementally improve
the current logic as well as work towards merging your readahead
rewrite?)
--
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2006-05-25 4:51 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-24 11:12 [PATCH 00/33] Adaptive read-ahead V12 Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 15:44 ` Andrew Morton
2006-05-25 19:26 ` Michael Stone
2006-05-25 19:40 ` David Lang
2006-05-25 22:01 ` Andrew Morton
2006-05-25 20:28 ` David Lang
2006-05-26 0:48 ` Michael Stone
2006-05-26 1:19 ` Wu Fengguang
2006-05-26 1:19 ` Wu Fengguang
2006-05-26 2:10 ` Jon Smirl
2006-05-26 3:14 ` Nick Piggin
2006-05-26 14:00 ` Andi Kleen
2006-05-26 16:25 ` Andrew Morton
2006-05-26 23:54 ` Folkert van Heusden
2006-05-27 0:00 ` Con Kolivas
2006-05-27 0:08 ` Con Kolivas
2006-05-28 22:20 ` Diego Calleja
2006-05-28 22:31 ` kernel
2006-05-29 3:04 ` Wu Fengguang
2006-05-29 3:04 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 02/33] radixtree: look-aside cache Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 03/33] radixtree: hole scanning functions Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 16:19 ` Andrew Morton
2006-05-26 7:04 ` Wu Fengguang
2006-05-26 7:04 ` Wu Fengguang
2006-05-26 11:05 ` Wu Fengguang
2006-05-26 11:05 ` Wu Fengguang
2006-05-26 16:19 ` Andrew Morton
2006-05-24 11:12 ` [PATCH 04/33] readahead: page flag PG_readahead Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 16:23 ` Andrew Morton
2006-05-26 7:06 ` Wu Fengguang
2006-05-26 7:06 ` Wu Fengguang
2006-05-24 12:27 ` Peter Zijlstra
2006-05-24 12:37 ` Wu Fengguang
2006-05-24 12:37 ` Wu Fengguang
2006-05-24 12:48 ` Peter Zijlstra
2006-05-24 11:12 ` [PATCH 05/33] readahead: refactor do_generic_mapping_read() Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 06/33] readahead: refactor __do_page_cache_readahead() Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 16:30 ` Andrew Morton
2006-05-25 22:33 ` Paul Mackerras
2006-05-25 22:40 ` Andrew Morton
2006-05-26 7:13 ` Wu Fengguang
2006-05-26 7:13 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 07/33] readahead: insert cond_resched() calls Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 08/33] readahead: common macros Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 5:56 ` Nick Piggin
2006-05-25 10:41 ` Wu Fengguang
2006-05-25 10:41 ` Wu Fengguang
2006-05-26 3:33 ` Nick Piggin
2006-05-26 6:59 ` Wu Fengguang
2006-05-26 6:59 ` Wu Fengguang
2006-05-25 13:42 ` Wu Fengguang
2006-05-25 13:42 ` Wu Fengguang
2006-05-25 14:38 ` Andrew Morton
2006-05-25 16:33 ` Andrew Morton
2006-05-24 11:12 ` [PATCH 09/33] readahead: events accounting Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 16:36 ` Andrew Morton
2006-05-26 7:09 ` Wu Fengguang
2006-05-26 7:09 ` Wu Fengguang
2006-05-27 13:20 ` Wu Fengguang
2006-05-27 13:20 ` Wu Fengguang
2006-05-29 8:19 ` Martin Peschke
2006-05-24 11:12 ` [PATCH 10/33] readahead: support functions Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 5:13 ` Nick Piggin
2006-05-25 11:13 ` Wu Fengguang
2006-05-25 11:13 ` Wu Fengguang
2006-05-25 16:48 ` Andrew Morton
2006-05-26 7:31 ` Wu Fengguang
2006-05-26 7:31 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 11/33] readahead: sysctl parameters Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-25 4:50 ` Nick Piggin [this message]
2006-05-25 12:12 ` [PATCH 12/33] readahead: min/max sizes Wu Fengguang
2006-05-25 12:12 ` Wu Fengguang
2006-05-24 11:12 ` [PATCH 13/33] readahead: state based method - aging accounting Wu Fengguang
2006-05-24 11:12 ` Wu Fengguang
2006-05-26 17:04 ` Andrew Morton
2006-05-27 6:22 ` Wu Fengguang
2006-05-27 6:22 ` Wu Fengguang
2006-05-27 7:00 ` Andrew Morton
2006-05-27 7:22 ` Wu Fengguang
2006-05-27 7:22 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 14/33] readahead: state based method - data structure Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-25 6:03 ` Nick Piggin
2006-05-25 10:43 ` Wu Fengguang
2006-05-25 10:43 ` Wu Fengguang
2006-05-26 17:05 ` Andrew Morton
2006-05-27 7:02 ` Wu Fengguang
2006-05-27 7:02 ` Wu Fengguang
2006-05-27 8:27 ` Wu Fengguang
2006-05-27 8:27 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 15/33] readahead: state based method - routines Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-26 17:15 ` Andrew Morton
2006-05-27 2:06 ` Wu Fengguang
2006-05-27 2:06 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 17/33] readahead: context based method Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-25 5:26 ` Nick Piggin
2006-05-25 8:03 ` Wu Fengguang
2006-05-25 8:03 ` Wu Fengguang
2006-05-26 17:23 ` Andrew Morton
2006-05-27 2:12 ` Wu Fengguang
2006-05-27 2:12 ` Wu Fengguang
2006-05-26 17:27 ` Andrew Morton
2006-05-27 8:04 ` Wu Fengguang
2006-05-27 8:04 ` Wu Fengguang
2006-05-24 12:37 ` Peter Zijlstra
2006-05-24 13:33 ` Wu Fengguang
2006-05-24 13:33 ` Wu Fengguang
2006-05-24 15:53 ` Peter Zijlstra
2006-05-25 1:25 ` Wu Fengguang
2006-05-25 1:25 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 18/33] readahead: initial method - guiding sizes Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 19/33] readahead: initial method - thrashing guard size Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 20/33] readahead: initial method - expected read size Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-25 5:34 ` [PATCH 22/33] readahead: initial method Nick Piggin
2006-05-25 8:59 ` Wu Fengguang
2006-05-25 8:59 ` Wu Fengguang
2006-05-26 17:29 ` [PATCH 20/33] readahead: initial method - expected read size Andrew Morton
2006-05-27 6:38 ` Wu Fengguang
2006-05-27 6:38 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 23/33] readahead: backward prefetching method Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-26 17:37 ` Nate Diller
2006-05-26 19:22 ` Nathan Scott
2006-05-28 12:30 ` Wu Fengguang
2006-05-28 12:30 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 24/33] readahead: seeking reads method Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 25/33] readahead: thrashing recovery method Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 26/33] readahead: call scheme Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 27/33] readahead: laptop mode Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-26 17:38 ` Andrew Morton
2006-05-24 11:13 ` [PATCH 28/33] readahead: loop case Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 14:01 ` Limin Wang
2006-05-25 15:48 ` wfg
2006-05-25 15:48 ` wfg
2006-05-24 11:13 ` [PATCH 29/33] readahead: nfsd case Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 30/33] readahead: turn on by default Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 31/33] readahead: debug radix tree new functions Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 32/33] readahead: debug traces showing accessed file names Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
2006-05-24 11:13 ` [PATCH 33/33] readahead: debug traces showing read patterns Wu Fengguang
2006-05-24 11:13 ` Wu Fengguang
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