From: Rik van Riel <riel@redhat.com>
To: Shaohua Li <shli@kernel.org>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
fengguang.wu@intel.com, minchan@kernel.org
Subject: Re: [patch v2]swap: add a simple random read swapin detection
Date: Mon, 27 Aug 2012 08:57:00 -0400 [thread overview]
Message-ID: <503B6E9C.50904@redhat.com> (raw)
In-Reply-To: <20120827040037.GA8062@kernel.org>
On 08/27/2012 12:00 AM, Shaohua Li wrote:
> The swapin readahead does a blind readahead regardless if the swapin is
> sequential. This is ok for harddisk and random read, because read big size has
> no penality in harddisk, and if the readahead pages are garbage, they can be
> reclaimed fastly. But for SSD, big size read is more expensive than small size
> read. If readahead pages are garbage, such readahead only has overhead.
>
> This patch addes a simple random read detection like what file mmap readahead
> does. If random read is detected, swapin readahead will be skipped. This
> improves a lot for a swap workload with random IO in a fast SSD.
>
> I run anonymous mmap write micro benchmark, which will triger swapin/swapout.
> runtime changes with path
> randwrite harddisk -38.7%
> seqwrite harddisk -1.1%
> randwrite SSD -46.9%
> seqwrite SSD +0.3%
>
> For both harddisk and SSD, the randwrite swap workload run time is reduced
> significant. sequential write swap workload hasn't chanage.
Very nice results!
> Signed-off-by: Shaohua Li <shli@fusionio.com>
Acked-by: Rik van Riel <riel@redhat.com>
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next prev parent reply other threads:[~2012-08-27 12:57 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-27 4:00 [patch v2]swap: add a simple random read swapin detection Shaohua Li
2012-08-27 12:57 ` Rik van Riel [this message]
2012-08-27 14:52 ` Konstantin Khlebnikov
2012-08-30 10:36 ` [patch v3]swap: " Shaohua Li
2012-08-30 16:03 ` Rik van Riel
2012-08-30 17:42 ` Minchan Kim
2012-09-03 7:21 ` [patch v4]swap: " Shaohua Li
2012-09-03 8:32 ` Minchan Kim
2012-09-03 11:46 ` Shaohua Li
2012-09-03 19:02 ` Konstantin Khlebnikov
2012-09-03 19:05 ` Rik van Riel
2012-09-04 7:34 ` Konstantin Khlebnikov
2012-09-04 14:15 ` Rik van Riel
2012-09-06 11:08 ` [PATCH RFC] mm/swap: automatic tuning for swapin readahead Konstantin Khlebnikov
2012-09-06 11:08 ` Konstantin Khlebnikov
2012-10-01 23:00 ` Hugh Dickins
2012-10-01 23:00 ` Hugh Dickins
2012-10-02 8:58 ` Konstantin Khlebnikov
2012-10-02 8:58 ` Konstantin Khlebnikov
2012-10-03 21:07 ` Hugh Dickins
2012-10-03 21:07 ` Hugh Dickins
2012-10-04 16:23 ` Konstantin Khlebnikov
2012-10-08 22:09 ` Hugh Dickins
2012-10-08 22:09 ` Hugh Dickins
2012-10-08 22:16 ` Andrew Morton
2012-10-08 22:16 ` Andrew Morton
2012-10-09 7:53 ` Konstantin Khlebnikov
2012-10-09 7:53 ` Konstantin Khlebnikov
2012-10-16 0:50 ` Shaohua Li
2012-10-16 0:50 ` Shaohua Li
2012-10-22 7:36 ` Shaohua Li
2012-10-22 7:36 ` Shaohua Li
2012-10-23 5:16 ` Hugh Dickins
2012-10-23 5:16 ` Hugh Dickins
2012-10-23 5:51 ` Shaohua Li
2012-10-23 5:51 ` Shaohua Li
2012-10-23 13:41 ` Rik van Riel
2012-10-23 13:41 ` Rik van Riel
2012-10-24 1:13 ` Shaohua Li
2012-10-24 1:13 ` Shaohua Li
2012-11-06 5:36 ` Shaohua Li
2012-11-06 5:36 ` Shaohua Li
2012-11-14 9:48 ` Hugh Dickins
2012-11-14 9:48 ` Hugh Dickins
2012-11-19 2:33 ` Shaohua Li
2012-11-19 2:33 ` Shaohua Li
2012-09-03 22:03 ` [patch v4]swap: add a simple random read swapin detection Minchan Kim
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