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Re: [Xen-devel] Reducing I/O introduced domain scheduling

To: "Keir Fraser" <keir@xxxxxxx>
Subject: Re: [Xen-devel] Reducing I/O introduced domain scheduling
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Tue, 12 Oct 2010 19:55:12 +1100
Cc: Paul Durrant <Paul.Durrant@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, "Dong, Eddie" <eddie.dong@xxxxxxxxx>, "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>
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Thread-topic: [Xen-devel] Reducing I/O introduced domain scheduling
Gplpv has supported all disks pv since the beginning. Recent versions turn off 
pv for the CDROM as qemu is more flexible (real CDROM works properly etc) but I 
think only under xen 3.4.1 or newer

Sent from my iPhone

On 12/10/2010, at 19:48, "Keir Fraser" <keir@xxxxxxx> wrote:

> On 12/10/2010 08:19, "Dong, Eddie" <eddie.dong@xxxxxxxxx> wrote:
>>> First of all have you tested with PV drivers? Performance tests with
>>> no PV drivers are not that interesting.
>> We used PV driver as more as possible, however the C disk in Windows guest
>> doesn't support PV yet. (A task in BIOS side or Win HAL side?)
> Running the system disk in PV mode certainly works okay with the Citrix PV
> drivers. Might this simply be a current limitation of the GPLPV drivers? If
> so, I definitely think you are better off putting effort into removing that
> limitation, rather than implementing your proposed optimisation. You will
> definitely get a bigger perf boost that way, and no suspicious hypervisor
> hacks needed.
> Cc'ing James Harper, who will best know what the current GPLPV drivers
> can/can't do. Also Paul Durrant, who can likely help with advice on how to
> PV up the Windows system disk.
> -- Keir

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