Re: [Xen-users] VCPU amount

["Ferreira, N. L. (Nuno)" <n.l.ferreira@xxxxx>]

Hi Fajar

And BTW, are these domU HVM settings also applicable to a PV domU?
Cheers,
Nuno

Fajar A. Nugraha wrote:
> On all domU config I use something like this
> (relevant cpu settings for windows HVM)
>
> vcpus=1
> cpus="1-7"
> cpu_cap=100
> cpu_weight=128
>
> it means I only use 1 vcpu, and it can be in cpu 1-7 (thus leaving
> cpu0 for dom0 exclusive usage). This ensures dom0 can handle disk and
> network requests for domUs at all times.
>
> If you want to give some domU priority over another, adjust cpu_weight
> as necessary.
>
> Note that on Windows HVM you probably need GPLPV to have a usable
> performance. However when using GPLPV,  I/O throughput with vcpus >1
> is lower when compared to vcpus=1 (although it's still MUCH higher
> compared to emulated QEMU drivers). So you see, adding vcpu does not
> always mean higher performance.
>
> You need to experiment and see which settings suit you best. Probably
> vcpus=1 for db server and vcpus=6 for terminal server (that is
> assuming your windows version can handle 6 cpus).
>
> Regards,
>
> Fajar
>
> _______________________________________________
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> http://lists.xensource.com/xen-users
>   

--
==============================================
Nuno Ricardo Santos Loureiro da Silva Ferreira

NMR Spectroscopy Research Group
Bijvoet Center for Biomolecular Research
Utrecht University
Bloembergen gebouw
Padualaan 8, 3584 CH Utrecht
The Netherlands

P: +31.(0)30.253 9932
F: +31.(0)30.253 2652
E: n.l.ferreira@xxxxx
W: http://nmr.chem.uu.nl
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