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Date: Mon, 11 Jan 2010 09:32:44 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Re: [RFC][PATCH] performance improvement for windows
	guests, running on top of virtio block device
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To: Avi Kivity <avi@redhat.com>
Cc: Vadim Rozenfeld <vrozenfe@redhat.com>, Dor Laor <dlaor@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Christoph Hellwig <hch@lst.de>

On 01/11/2010 09:31 AM, Avi Kivity wrote:
> On 01/11/2010 05:22 PM, Anthony Liguori wrote:
>>
>> Based on our experiences with virtio-net, what I'd suggest is to make 
>> a lot of tunable options (ring size, various tx mitigation schemes, 
>> timeout durations, etc) and then we can do some deep performance 
>> studies to see how things interact with each other.
>>
>> I think we should do that before making any changes because I'm 
>> deeply concerned that we'll introduce significant performance 
>> regressions.
>>
>
> I agree.  We can start with this patch, with a tunable depth, 
> defaulting to current behaviour.

I wouldn't be opposed to that provided we made it clear that these 
options were not supported long term.  I don't want management tools 
(like libvirt) to start relying on them.

Regards,

Anthony Liguori