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From: Wu Fengguang <wfg@mail.ustc.edu.cn>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH 04/16] radix-tree: look-aside cache
Date: Thu, 10 Nov 2005 16:30:19 +0800	[thread overview]
Message-ID: <20051110083019.GA5797@mail.ustc.edu.cn> (raw)
In-Reply-To: <4372EDA1.3000103@yahoo.com.au>

On Thu, Nov 10, 2005 at 05:50:09PM +1100, Nick Piggin wrote:
> But it isn't *really* constant time lookups? I mean you'll
> always have the O(logn) lookup. Amortised I guess that
> becomes insignificant?

For sequential scan, I get 64*O(1) + 1*O(logn), that's pretty much gain.

> Briefly: is there a reason why you couldn't use gang lookups
> instead? (Sorry I haven't been able to read and understand your
> actual readahead code).

Because they have different semantics, one cannot replace the another.

> Profile numbers would be great for the cached / non-cached cases.

Ok, I'll do it, but at some time later. Currently I have several tasks that
need immediate handling, and that will take about a week. See you then :)

Regards,
Wu

  reply	other threads:[~2005-11-10  8:30 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-09 13:49 [PATCH 00/16] Adaptive read-ahead V7 Wu Fengguang
2005-11-09 13:49 ` [PATCH 01/16] mm: delayed page activation Wu Fengguang
2005-11-10  0:21   ` Nick Piggin
2005-11-10  3:15     ` Wu Fengguang
2005-11-10  9:17   ` Peter Zijlstra
2005-11-10 10:30     ` Wu Fengguang
2005-11-09 13:49 ` [PATCH 02/16] mm: balance page aging between zones Wu Fengguang
2005-11-09 13:49 ` [PATCH 03/16] radixtree: sync with mainline Wu Fengguang
2005-11-09 13:49 ` [PATCH 04/16] radix-tree: look-aside cache Wu Fengguang
2005-11-09 23:31   ` Nick Piggin
2005-11-10  5:25     ` Wu Fengguang
2005-11-10  6:50       ` Nick Piggin
2005-11-10  8:30         ` Wu Fengguang [this message]
2005-11-18 11:25         ` Wu Fengguang
2005-11-18 12:12           ` Wu Fengguang
2005-11-09 13:49 ` [PATCH 05/16] readahead: some preparation Wu Fengguang
2005-11-18  7:46   ` 2.6.15-rc1-mm2 Andrew Morton
2005-11-18  8:56     ` 2.6.15-rc1-mm2 Benoit Boissinot
2005-11-18  9:04       ` 2.6.15-rc1-mm2 Andrew Morton
2005-11-18  9:13         ` 2.6.15-rc1-mm2 Benoit Boissinot
2005-11-18 13:43         ` 2.6.15-rc1-mm2 Rafael J. Wysocki
2005-11-18 10:10     ` 2.6.15-rc1-mm2 Mauro Carvalho Chehab
2005-11-18 10:55     ` 2.6.15-rc1-mm2 Wu Fengguang
2005-11-18 11:29     ` 2.6.15-rc1-mm2 Andy Whitcroft
2005-11-18 16:29     ` 2.6.15-rc1-mm2 Michael Krufky
2005-11-20  0:23     ` 2.6.15-rc1-mm2 Michal Piotrowski
2005-11-20  8:04       ` 2.6.15-rc1-mm2 Hugh Dickins
2005-11-20 12:53         ` 2.6.15-rc1-mm2 Michal Piotrowski
2005-11-09 13:49 ` [PATCH 06/16] readahead: call scheme Wu Fengguang
2005-11-09 13:49 ` [PATCH 07/16] readahead: tunable parameters Wu Fengguang
2005-11-09 13:49 ` [PATCH 08/16] readahead: state based method Wu Fengguang
2005-11-09 13:49 ` [PATCH 09/16] readahead: context " Wu Fengguang
2005-11-09 13:49 ` [PATCH 10/16] readahead: other methods Wu Fengguang
2005-11-09 13:49 ` [PATCH 11/16] readahead: mandatory thrashing protection Wu Fengguang
2005-11-09 13:49 ` [PATCH 12/16] readahead: events accounting Wu Fengguang
2005-11-09 13:49 ` [PATCH 13/16] readahead: page aging accounting Wu Fengguang
2005-11-09 13:49 ` [PATCH 14/16] readahead: laptop mode support Wu Fengguang
2005-11-09 13:49 ` [PATCH 15/16] readahead: disable look-ahead for loopback file Wu Fengguang
2005-11-09 13:49 ` [PATCH 16/16] io: reduce lantency Wu Fengguang
2005-11-09 20:39 ` [PATCH 00/16] Adaptive read-ahead V7 Christoph Lameter
2005-11-10 10:19   ` Wu Fengguang

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