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Re: [Xen-devel] Is QoS of virtual disk not necessary?


  • To: Satoshi Uchida <s-uchida@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
  • Date: Wed, 22 Aug 2007 13:39:43 +0100
  • Delivery-date: Wed, 22 Aug 2007 05:40:28 -0700
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-index: Acfkn1AvjVodwXJpTAeEc3jziy7dgwAGjNU+
  • Thread-topic: [Xen-devel] Is QoS of virtual disk not necessary?

First impression was a lot of plumbing and not much in the way of moving
parts. Also of course we have CFQ on Linux -- I suspect the kinds of changes
you are suggesting would not be popular with kernel maintainers since they
will argue there is already an I/O scheduling subsystem. :-)

On the other hand, if you want to run a block driver in a driver domain (and
so outside dom0) then having a programmatic scheduling interface via
xenstore is quite nice...

 -- Keir

On 22/8/07 10:32, "Satoshi Uchida" <s-uchida@xxxxxxxxxxxxx> wrote:

> Hi,
> 
> I sent RFC and a patch-set of I/O framework for virtual disk in order to
> introduce QoS in end of July.
>> http://lists.xensource.com/archives/html/xen-devel/2007-07/msg00863.html
> But no one responded to it.
> 
> I think that when many virtual machines run on one physical machine, QoS of
> machine resources will be necessary.
> For example, in server consolidation, integrated servers have various roles
> and are different in the desired resources.
> So, distribution of resources is very important for stabilization.
> As other example, it will be avoided to be affected by jobs of other people in
> consolidation of office platform.
> 
> CPU and memory are controlled (allocated) at Xen hypervisor. (This is OS
> agnostic)
> Is similar controller for I/O not necessary?
> 
> Linux adopts CFQ which is fair scheduler which is suitable for desktop system.
> But, privileged domain will be not only Linux in future.
> I think that such function should be developed in Xen hypervisor or virtual
> block driver framework.
> 
> Does anyone have opinions or idea?
> Please reply comments.
> 
>  --------------------------------------------------
>  Satoshi UCHIDA 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



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