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From: Pradeep Kiruvale <pradeepkiruvale@gmail.com>
To: qemu-devel@nongnu.org,
	"qemu-discuss@nongnu.org" <qemu-discuss@nongnu.org>
Subject: [Qemu-devel] Virtio-9p and cgroup io-throttling
Date: Thu, 7 Apr 2016 11:48:27 +0200	[thread overview]
Message-ID: <CAJ2SuLkmYnN+mrZNX0Ke77P=3+9B1a_U8wO+hPQe9ejBDLTsfA@mail.gmail.com> (raw)

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Hi All,

I am using virtio-9p for sharing the file between host and guest. To test
the shared file I do read/write options in the guest.To have controlled io,
I am using cgroup blkio.

While using cgroup I am facing two issues,Please find the issues below.

1. When I do IO throttling using the cgroup the read throttling works fine
but the write throttling does not wok. It still bypasses these throttling
control and does the default, am I missing something here?

I use the following commands to create VM, share the files and to
read/write from guest.

*Create vm*
qemu-system-x86_64 -balloon none .......-name vm0 -cpu host -m 128 -smp 1
-enable-kvm -parallel .... -fsdev
local,id=sdb1,path=/mnt/sdb1,security_model=none,writeout=immediate -device
virtio-9p-pci,fsdev=sdb1,mount_tag=sdb1

*Mount file*
mount -t 9p -o trans=virtio,version=9p2000.L sdb1 /sdb1_ext4 2>>dd.log &&
sync

touch /sdb1_ext4/dddrive

*Write test*
dd if=/dev/zero of=/sdb1_ext4/dddrive bs=4k count=800000 oflag=direct >>
dd.log 2>&1 && sync

*Read test*
dd if=/sdb1_ext4/dddrive of=/dev/null >> dd.log 2>&1 && sync

2. The other issue is when I run "dd" command inside guest  it creates
multiple threads to write/read. I can see those on host using iotop is this
expected behavior?

Regards,
Pradeep

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             reply	other threads:[~2016-04-07  9:48 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-07  9:48 Pradeep Kiruvale [this message]
2016-04-08  8:10 ` [Qemu-devel] Virtio-9p and cgroup io-throttling Greg Kurz
2016-04-08  9:51   ` Pradeep Kiruvale
2016-04-08 12:40     ` Greg Kurz
2016-04-08 12:55       ` Pradeep Kiruvale
2016-04-08 14:58         ` Greg Kurz
2016-04-11 14:18           ` Pradeep Kiruvale

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