From: Andrew Morton <akpm@osdl.org>
To: Jens Axboe <axboe@suse.de>
Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, npiggin@suse.de,
linux-mm@kvack.org
Subject: Re: Lockless page cache test results
Date: Wed, 26 Apr 2006 13:12:00 -0700 [thread overview]
Message-ID: <20060426131200.516cbabc.akpm@osdl.org> (raw)
In-Reply-To: <20060426191557.GA9211@suse.de>
Jens Axboe <axboe@suse.de> wrote:
>
> With a 16-page gang lookup in splice, the top profile for the 4-client
> case (which is now at 4GiB/sec instead of 3) are:
>
> samples % symbol name
> 30396 36.7217 __do_page_cache_readahead
> 25843 31.2212 find_get_pages_contig
> 9699 11.7174 default_idle
__do_page_cache_readahead() should use gang lookup. We never got around to
that, mainly because nothing really demonstrated a need.
It's a problem that __do_page_cache_readahead() is being called at all -
with everything in pagecache we should be auto-turning-off readahead. This
happens because splice is calling the low-level do_pagecache_readahead().
If you convert it to use page_cache_readahead(), that will all vanish if
readahead is working right.
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@osdl.org>
To: Jens Axboe <axboe@suse.de>
Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, npiggin@suse.de,
linux-mm@kvack.org
Subject: Re: Lockless page cache test results
Date: Wed, 26 Apr 2006 13:12:00 -0700 [thread overview]
Message-ID: <20060426131200.516cbabc.akpm@osdl.org> (raw)
In-Reply-To: <20060426191557.GA9211@suse.de>
Jens Axboe <axboe@suse.de> wrote:
>
> With a 16-page gang lookup in splice, the top profile for the 4-client
> case (which is now at 4GiB/sec instead of 3) are:
>
> samples % symbol name
> 30396 36.7217 __do_page_cache_readahead
> 25843 31.2212 find_get_pages_contig
> 9699 11.7174 default_idle
__do_page_cache_readahead() should use gang lookup. We never got around to
that, mainly because nothing really demonstrated a need.
It's a problem that __do_page_cache_readahead() is being called at all -
with everything in pagecache we should be auto-turning-off readahead. This
happens because splice is calling the low-level do_pagecache_readahead().
If you convert it to use page_cache_readahead(), that will all vanish if
readahead is working right.
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next prev parent reply other threads:[~2006-04-26 20:09 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-26 13:53 Lockless page cache test results Jens Axboe
2006-04-26 14:43 ` Nick Piggin
2006-04-26 14:43 ` Nick Piggin
2006-04-26 19:46 ` Jens Axboe
2006-04-26 19:46 ` Jens Axboe
2006-04-27 5:39 ` Chen, Kenneth W
2006-04-27 5:39 ` Chen, Kenneth W
2006-04-27 6:07 ` Nick Piggin
2006-04-27 6:07 ` Nick Piggin
2006-04-27 6:15 ` Andi Kleen
2006-04-27 6:15 ` Andi Kleen
2006-04-27 7:51 ` Chen, Kenneth W
2006-04-27 7:51 ` Chen, Kenneth W
2006-04-26 16:55 ` Andrew Morton
2006-04-26 16:55 ` Andrew Morton
2006-04-26 17:42 ` Jens Axboe
2006-04-26 17:42 ` Jens Axboe
2006-04-26 18:10 ` Andrew Morton
2006-04-26 18:10 ` Andrew Morton
2006-04-26 18:23 ` Jens Axboe
2006-04-26 18:23 ` Jens Axboe
2006-04-26 18:46 ` Andrew Morton
2006-04-26 18:46 ` Andrew Morton
2006-04-26 19:21 ` Jens Axboe
2006-04-26 19:21 ` Jens Axboe
2006-04-27 5:58 ` Nick Piggin
2006-04-27 5:58 ` Nick Piggin
2006-04-26 18:34 ` Christoph Lameter
2006-04-26 18:34 ` Christoph Lameter
2006-04-26 18:47 ` Andrew Morton
2006-04-26 18:47 ` Andrew Morton
2006-04-26 18:48 ` Christoph Lameter
2006-04-26 18:48 ` Christoph Lameter
2006-04-26 18:49 ` Jens Axboe
2006-04-26 18:49 ` Jens Axboe
2006-04-26 20:31 ` Christoph Lameter
2006-04-26 20:31 ` Christoph Lameter
2006-04-28 14:01 ` David Chinner
2006-04-28 14:01 ` David Chinner
2006-04-28 14:10 ` David Chinner
2006-04-28 14:10 ` David Chinner
2006-04-30 9:49 ` Nick Piggin
2006-04-30 11:20 ` Nick Piggin
2006-04-30 11:20 ` Nick Piggin
2006-04-30 11:39 ` Jens Axboe
2006-04-30 11:39 ` Jens Axboe
2006-04-30 11:44 ` Nick Piggin
2006-04-26 18:58 ` Christoph Hellwig
2006-04-26 18:58 ` Christoph Hellwig
2006-04-26 19:02 ` Jens Axboe
2006-04-26 19:02 ` Jens Axboe
2006-04-26 19:00 ` Linus Torvalds
2006-04-26 19:00 ` Linus Torvalds
2006-04-26 19:15 ` Jens Axboe
2006-04-26 19:15 ` Jens Axboe
2006-04-26 20:12 ` Andrew Morton [this message]
2006-04-26 20:12 ` Andrew Morton
2006-04-27 7:45 ` Jens Axboe
2006-04-27 7:47 ` Jens Axboe
2006-04-27 7:47 ` Jens Axboe
2006-04-27 7:57 ` Nick Piggin
2006-04-27 7:57 ` Nick Piggin
2006-04-27 8:02 ` Nick Piggin
2006-04-27 8:02 ` Nick Piggin
2006-04-27 9:00 ` Jens Axboe
2006-04-27 9:00 ` Jens Axboe
2006-04-27 13:36 ` Nick Piggin
2006-04-27 13:36 ` Nick Piggin
2006-04-27 8:36 ` Jens Axboe
2006-04-27 8:36 ` Jens Axboe
2006-04-28 11:28 ` Wu Fengguang
2006-04-28 11:28 ` Wu Fengguang
2006-04-28 11:28 ` Wu Fengguang
2006-04-27 5:49 ` Nick Piggin
2006-04-27 5:49 ` Nick Piggin
2006-04-27 15:12 ` Linus Torvalds
2006-04-27 15:12 ` Linus Torvalds
2006-04-28 4:54 ` Nick Piggin
2006-04-28 4:54 ` Nick Piggin
2006-04-28 5:34 ` Linus Torvalds
2006-04-28 5:34 ` Linus Torvalds
2006-04-27 9:35 ` Jens Axboe
2006-04-27 5:22 ` Nick Piggin
2006-04-27 5:22 ` Nick Piggin
2006-04-26 18:57 ` Jens Axboe
2006-04-27 2:19 ` KAMEZAWA Hiroyuki
2006-04-27 2:19 ` KAMEZAWA Hiroyuki
2006-04-27 8:03 ` Jens Axboe
2006-04-27 8:03 ` Jens Axboe
2006-04-27 11:16 ` Jens Axboe
2006-04-27 11:16 ` Jens Axboe
2006-04-27 11:41 ` KAMEZAWA Hiroyuki
2006-04-27 11:41 ` KAMEZAWA Hiroyuki
2006-04-27 11:45 ` Jens Axboe
2006-04-27 11:45 ` Jens Axboe
2006-04-28 9:10 ` Pavel Machek
2006-04-28 9:10 ` Pavel Machek
2006-04-28 9:21 ` Jens Axboe
2006-04-28 9:21 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2006-04-28 16:58 Al Boldi
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