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Re: [Libvir] CPU pinning of domains at creation time



On Thu, 11 Oct 2007 09:00:14 -0400 Daniel Veillard wrote:
>   There are a few things I gathered on this issue. This affects 
> NUMA setups, where basically if a domain must be placed on a given cell
> it is not good to let the hypervisor place it first with its own heuristics
> and then later migrate it to a different set of CPU, but better to 
> instruct the hypervisor to start said domain on the given set.

That sounds good to me ! 

>    - For Xen it is possible to instruct the hypervisor by passing 
>      (cpus '2,3') in the SExpr where the argument is a list of
>      the physical processors allowed

Yeah, we can set CPUs to the domain by passing that and
the physical CPUs will be pinned to VCPUs.

>    - for the mapping at the XML level I suggest to use a simple extension
>      to the <vcpu>n</vcpu> and extend it to
>      <vcpu cpuset='2,3'>n</vcpu>
>      with a limited syntax which is just the comma separated list of
>      allowed CPU numbers (if the code actually detects such a cpuset is
>      in effect i.e. in general this won't be added).

How about adding <cpus>2,3</cpus> to the XML simply ?
And we may set 64 CPUs, it is hard to set all of them by each number.
(i.e. we have to set cpuset='1,2,3,4,5,6,7,8,9,10,....,64')
So I hope to use - (range) and ^ (negation) to set cpuset as Ryan said.

Regards,
Saori Fukuta


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