From: Jeff Garzik <jeff@garzik.org>
To: Corrado Zoccolo <czoccolo@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>,
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: NCQ SSDs do not need read queue merging
Date: Mon, 11 Jan 2010 06:25:29 -0500 [thread overview]
Message-ID: <4B4B0AA9.5020900@garzik.org> (raw)
In-Reply-To: <1263157461-12294-1-git-send-email-czoccolo@gmail.com>
On 01/10/2010 04:04 PM, Corrado Zoccolo wrote:
> NCQ SSDs' performances are not affected by
> distance of read requests, so there is no point in having
> overhead to merge such queues.
>
> Non-NCQ SSDs showed regression in some special cases, so
> they are ruled out by this patch.
>
> This patch intentionally doesn't affect writes, so
> it changes the queued[] field, to be indexed by
> READ/WRITE instead of SYNC/ASYNC, and only compute proximity
> for queues with WRITE requests.
>
> Signed-off-by: Corrado Zoccolo<czoccolo@gmail.com>
That's not really true. Overhead always increases as the total number
of ATA commands issued increases.
Jeff
next prev parent reply other threads:[~2010-01-11 11:25 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-30 12:10 [PATCH] cfq-iosched: non-rot devices do not need " Corrado Zoccolo
2009-12-30 18:45 ` Jens Axboe
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 [this message]
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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