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Re: [Xen-users] SMP enabled Dom0 or not?

To: "Stefan de Konink" <skinkie@xxxxxxxxx>
Subject: Re: [Xen-users] SMP enabled Dom0 or not?
From: "Todd Deshane" <deshantm@xxxxxxxxx>
Date: Sat, 14 Jun 2008 19:51:09 -0400
Cc: xen-users <xen-users@xxxxxxxxxxxxxxxxxxx>
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Hi Stefan,

On Sat, Jun 14, 2008 at 7:27 PM, Stefan de Konink <skinkie@xxxxxxxxx> wrote:
Hello,


I wonder if the performance of a Xen machine can be increased by disabling SMP in the Linux kernel by default, basically having one of the 8 processors tied to dom0.

In my scenario I use NFS or iSCSI as file backend. Looking at NFS there will be a lot of tapdrives, while in the iSCSI scenario there is fewer overhead in userspace processes.

Could anyone give me a hint on the performance increase or decrease using SMP vs Uniprocessor?


In the original "Xen and the Art of Virtualization" they actually disabled SMP and had better IO performance. I don't know if this is still true.

Take a look at:
http://research.microsoft.com/~tharris/papers/2003-sosp.pdf
www.clarkson.edu/class/cs644/xen/files/repeatedxen-usenix04.pdf

Cheers,
Todd

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