From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39637) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avQdK-0005cB-Hh for qemu-devel@nongnu.org; Wed, 27 Apr 2016 10:40:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1avQdG-00084w-AY for qemu-devel@nongnu.org; Wed, 27 Apr 2016 10:40:06 -0400 MIME-Version: 1.0 In-Reply-To: <20160427083840.GA27160@igalia.com> References: <20160427083840.GA27160@igalia.com> Date: Wed, 27 Apr 2016 16:39:58 +0200 Message-ID: From: Pradeep Kiruvale Content-Type: multipart/alternative; boundary=001a114253264c0e040531786294 Subject: Re: [Qemu-devel] [Qemu-discuss] iolimits for virtio-9p List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alberto Garcia Cc: qemu-devel@nongnu.org, "qemu-discuss@nongnu.org" --001a114253264c0e040531786294 Content-Type: text/plain; charset=UTF-8 On 27 April 2016 at 10:38, Alberto Garcia wrote: > On Wed, Apr 27, 2016 at 09:29:02AM +0200, Pradeep Kiruvale wrote: > > > Thanks for the reply. I am still in the early phase, I will let you > > know if any changes are needed for the APIs. > > > > We might also have to implement throttle-group.c for 9p devices, if > > we want to apply throttle for group of devices. > > Fair enough, but again please note that: > > - throttle-group.c is not meant to be generic, but it's tied to > BlockDriverState / BlockBackend. > - it is currently being rewritten: > https://lists.gnu.org/archive/html/qemu-block/2016-04/msg00645.html > > If you can explain your use case with a bit more detail we can try to > see what can be done about it. > > We want to use virtio-9p for block io instead of virtio-blk-pci. But in case of virtio-9p we can just use fsdev devices, so we want to apply throttling (QoS) on these devices and as of now the io throttling only possible with the -drive option. As a work around we are doing the throttling using cgroup. It has its own costs. So, we want to have throttling for fsdev devices inside the qemu itself. I am just trying to understand and estimate time required for implementing it for the fsdevices. -Pradeep --001a114253264c0e040531786294 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On 27 April 2016 at 10:38, Alberto Garcia <berto@igalia.com> wrote:
On Wed, Apr 2= 7, 2016 at 09:29:02AM +0200, Pradeep Kiruvale wrote:

> Thanks for the reply. I am still in the early phase, I will let you > know if any changes are needed for the APIs.
>
> We might also have to implement throttle-group.c for 9p devices, if > we want to apply throttle for group of devices.

Fair enough, but again please note that:

- throttle-group.c is not meant to be generic, but it's tied to
=C2=A0 BlockDriverState / BlockBackend.
- it is currently being rewritten:
=C2=A0 https://lists.gnu.org/arch= ive/html/qemu-block/2016-04/msg00645.html

If you can explain your use case with a bit more detail we can try to
see what can be done about it.


We want to use =C2=A0virtio-9p for blo= ck io instead of virtio-blk-pci. But in case of
virtio-9p we can = just use fsdev devices, so we want to apply throttling (QoS)
on t= hese devices and as of now the io throttling only possible with the -drive = option.

As a work around we are doing the throttli= ng using cgroup. It has its own costs.
So, we want to have thrott= ling for fsdev devices inside the qemu itself. I am just
trying t= o understand and estimate time required for implementing it for the fsdevic= es.


-Pradeep


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