Re: [Xen-users] Performance of PVM and HVM

["Fajar A. Nugraha" <list@xxxxxxxxx>]

On Mon, Sep 17, 2012 at 10:12 AM, Robin hp <pingh.cd@xxxxxxxxx> wrote:
> Recently, I met a strange issue about vm's performance.
>
> I downloaded Jeremy's branch of xen/next-2.6.32 (version:2.6.32.57)for dom0,
> and compiled xen-4.1.3 source code for xend service, then I used Unixbench
> to test the performance of native, dom0, and domU(HVM and PVM). By the way,
> I set 4 vcpus and 2048M memory for each VM. And I got the following results:
>
> It seems that dom0's performance is so bad from native, and PVM so on.

How do you test native?

For "fair" comparison, you need to make sure that native has the same
cpu and memory as dom0/domU tested. For cpu, you can disable some of
them using /sys/devices/system/cpu/cpu1/online, and for memory you
might need to use "mem=2G" kernel boot parameter.

> But
> HVM's performance is better than my expected, it's so close to native.

Do you file:/ ? If yes, that would be the effect of dom0 cache. Try
using block devices with phy:/

Others might comment more about this.

-- 
Fajar

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