From: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
To: Shaohua Li <shaohua.li@intel.com>
Cc: linux-kernel@vger.kernel.org, jens.axboe@oracle.com,
jmoyer@redhat.com, czoccolo@gmail.com, yanmin.zhang@intel.com
Subject: Re: cfq-iosched: tiobench regression
Date: Thu, 24 Dec 2009 15:48:38 +0800 [thread overview]
Message-ID: <4B331CD6.1070207@cn.fujitsu.com> (raw)
In-Reply-To: <20091224005506.GA7879@sli10-desk.sh.intel.com>
Shaohua Li wrote:
> We see about 30% regression in tiobench 32 threads 80M file sequential read.
> The regression is caused by below commits.
>
> 5db5d64277bf390056b1a87d0bb288c8b8553f96
> The commit makes the slice too small. In the test, the slice is limitted
> to 2 * idle_slice(300ms/32 < 2*idle_slice). This dramatically impacts io
> thoughput. The low_latency knob used to be only impact random io, now it
> impacts sequential io too. Any idea to fix it?
Hi Shaohua,
IMHO this shouldn't be a problem. Currently, low_latency is used to improve
the latency for the whole system. If someone would like to achieve high throughput,
just turn off low_latency knob.
next prev parent reply other threads:[~2009-12-24 7:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-24 0:55 cfq-iosched: tiobench regression Shaohua Li
2009-12-24 7:48 ` Gui Jianfeng [this message]
2009-12-24 9:19 ` Shaohua Li
2009-12-24 11:40 ` Corrado Zoccolo
2009-12-25 10:16 ` Corrado Zoccolo
2009-12-28 2:02 ` Shaohua Li
2009-12-28 2:03 ` [PATCH]cfq-iosched: don't take requests with long distence as close Shaohua Li
2009-12-28 8:36 ` Corrado Zoccolo
2009-12-28 8:46 ` Shaohua Li
2009-12-28 9:11 ` Corrado Zoccolo
2009-12-28 9:28 ` Shaohua Li
2009-12-28 9:40 ` Corrado Zoccolo
2009-12-28 12:16 ` Jens Axboe
2010-01-04 14:58 ` Jeff Moyer
2010-01-05 21:16 ` Jeff Moyer
2010-01-06 1:19 ` Li, Shaohua
2010-01-07 13:44 ` Corrado Zoccolo
2010-01-07 14:30 ` Jeff Moyer
2010-01-11 5:20 ` Zhang, Yanmin
2010-01-11 15:05 ` Corrado Zoccolo
2010-01-12 2:43 ` Zhang, Yanmin
2010-01-15 19:32 ` Corrado Zoccolo
2010-01-15 19:45 ` Jeff Moyer
2010-01-15 20:24 ` Corrado Zoccolo
2010-01-15 20:26 ` Jeff Moyer
2009-12-28 3:19 ` [PATCH]cfq-iosched: split seeky coop queues after one slice Shaohua Li
2009-12-28 8:40 ` Corrado Zoccolo
2009-12-28 8:52 ` Shaohua Li
2010-01-04 15:04 ` Jeff Moyer
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