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Date: Wed, 04 Aug 2010 19:44:27 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with
	Linux 2.6.35?
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org, "Richard W.M. Jones" <rjones@redhat.com>, Gleb Natapov <gleb@redhat.com>, qemu-devel@nongnu.org

  On 08/04/2010 03:53 PM, Anthony Liguori wrote:
>
> So how do we enable support for more than 20 disks?  I think a 
> virtio-scsi is inevitable..

Not only for large numbers of disks, also for JBOD performance.  If you 
have one queue per disk you'll have low queue depths and high interrupt 
rates.  Aggregating many spindles into a single queue is important for 
reducing overhead.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.