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From: "Ouyang Zhaowei (Charles)" <ouyangzhaowei@huawei.com>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: <linux-kernel@vger.kernel.org>, <suoben@huawei.com>,
	<liuyingdong@huawei.com>, <weiping.ding@huawei.com>
Subject: xen-blkfront: weird behavior of "iostat" after VM live-migrate which xen-blkfront module has indirect descriptors
Date: Fri, 23 Jan 2015 15:59:00 +0800	[thread overview]
Message-ID: <54C1FF44.1090902@huawei.com> (raw)

Hi Roger,

We are testing the indirect feature of xen-blkfront module these days.
And we found that, after VM live-migrate a couple of times, the "%util" of iostat keeps being 100%, and there are several requests stock in "avgqu-sz".
We have checked some later version of Linux, and it happens on Ubuntu 14.04, Ubuntu 14.10 and RHEL 7.0.

The iostat shows like below:

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.00    0.00    0.00    0.00    0.00  100.00

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
xvda              0.00     0.00    0.00    0.00     0.00     0.00     0.00     4.00    0.00    0.00    0.00   0.00 100.00
dm-0              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
dm-1              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00

Could you tell us that why is this happening, is this a bug?

Thanks!

Ouyang Zhaowei


             reply	other threads:[~2015-01-23  8:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-23  7:59 Ouyang Zhaowei (Charles) [this message]
2015-01-23 11:15 ` Roger Pau Monné
2015-01-26  2:30   ` Ouyang Zhaowei (Charles)
2015-01-30  8:37     ` Ouyang Zhaowei (Charles)

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