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From: Jens Axboe <jens.axboe@oracle.com>
To: Corrado Zoccolo <czoccolo@gmail.com>
Cc: Linux-Kernel <linux-kernel@vger.kernel.org>,
	Jeff Moyer <jmoyer@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
	Shaohua Li <shaohua.li@intel.com>,
	Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Subject: Re: [PATCH] cfq-iosched: non-rot devices do not need queue merging
Date: Wed, 30 Dec 2009 19:45:35 +0100	[thread overview]
Message-ID: <20091230184535.GE4489@kernel.dk> (raw)
In-Reply-To: <1262175004-2132-1-git-send-email-czoccolo@gmail.com>

On Wed, Dec 30 2009, Corrado Zoccolo wrote:
> Non rotational devices' performances are not affected by
> distance of requests, so there is no point in having overhead
> to merge queues of nearby requests.

If the distance is zero, it may still make a big difference (at least
for writes). This check would be better as "ncq and doesn't suck", ala

        blk_queue_nonrot(q) && tagged

like we do elsewhere.

-- 
Jens Axboe


  reply	other threads:[~2009-12-30 18:45 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-30 12:10 Corrado Zoccolo
2009-12-30 18:45 ` Jens Axboe [this message]
2009-12-30 20:31   ` Corrado Zoccolo
2009-12-30 21:11     ` Jens Axboe
2009-12-30 21:21       ` Corrado Zoccolo
2009-12-30 21:34         ` Jens Axboe
2009-12-30 22:22           ` [PATCH] cfq-iosched: non-rot devices do not need read " Corrado Zoccolo
2010-01-04 14:47             ` Vivek Goyal
2010-01-04 16:36               ` Corrado Zoccolo
2010-01-04 16:51                 ` Jeff Moyer
2010-01-04 18:32                   ` Vivek Goyal
2010-01-04 18:37                   ` Corrado Zoccolo
2010-01-04 18:51                     ` Vivek Goyal
2010-01-04 19:04                       ` Jeff Moyer
2010-01-04 20:37                         ` Corrado Zoccolo
2010-01-05 14:58                           ` Jeff Moyer
2010-01-05 15:13                             ` Vivek Goyal
2010-01-05 21:19                               ` Jeff Moyer
2010-01-05 21:48                                 ` Corrado Zoccolo
2010-01-07 10:56                                   ` Kirill Afonshin
2010-01-07 13:38                                     ` Corrado Zoccolo
2010-01-07 14:36                                       ` Vivek Goyal
2010-01-07 17:00                                         ` Corrado Zoccolo
2010-01-07 18:37                                           ` Vivek Goyal
2010-01-07 20:16                                             ` Corrado Zoccolo
2010-01-08 18:53                                               ` Vivek Goyal
2010-01-10 12:55                                   ` Corrado Zoccolo
2010-01-10 21:04             ` [PATCH] cfq-iosched: NCQ SSDs " Corrado Zoccolo
2010-01-10 21:08               ` Corrado Zoccolo
2010-01-11 11:25               ` Jeff Garzik
2010-01-11 12:26                 ` Corrado Zoccolo
2010-01-11 13:13                   ` Jens Axboe
2010-01-11 13:18                     ` Jeff Garzik
2010-01-11 13:24                       ` Jens Axboe
2010-01-11 14:53                       ` Corrado Zoccolo
2010-01-11 16:44                         ` Vivek Goyal
2010-01-11 17:00                           ` Corrado Zoccolo
2010-01-11 17:07                             ` Vivek Goyal
2010-01-11 19:05                               ` Corrado Zoccolo
2010-01-11 17:11                             ` Vivek Goyal
2010-01-11 19:09                               ` Corrado Zoccolo

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