[Xen-users] present domU with 1 CPU with multiple cores

[Jonathan Salomon <jonathan@xxxxxxxxxxxxx>]

Hi all,

 

I have a machine with 2 physical CPUs with each 2 cores and as such when I do cat /proc/cpuinfo on Dom0 it reports 4 CPUs. I want to run a couple of DomU instances on this machine. However to make sure that Dom0 will always respond even when the DomU instances have a high load, I want to keep CPU 0 available only for Dom0. Therefore in the DomU config files I’m using the following CPU definition: cpus="1-3". Does it makes sense to do this? Or would Xen handle this better on its own?

 

Anyway, so one of the DomU instances runs software that I have bought a 1CPU license for. Consequently I have to set ‘vcpus=1’ otherwise it will tell me that I do not have a multiple CPU license. However it is ok to have 1 CPU with multiple cores. Therefore to speed it up I was wondering how I can tell Xen to assign say 2 cores to this DomU instance, but present it as 1 CPU with 2 cores.

 

Also how do I see on which physical CPU a DomU instance is running? When I set cpus=”1-3” and vcpus=”1” , then ‘xm top’ will show that the instance is running on vCPU 0 (which I assume is CPU 0 of that instance, not physical CPU0 since I deliberately pinned it to CPUs 1-3). Also ‘xm list’ will show how many vCPUs that DomU runs on, but not on which physical CPU.

 

Thanks!

 

Best wishes,

 

Jonathan Salomon

IT Manager

Panaya Inc. – Cut 50% of your SAP upgrade cost with automation software.

Tel: +972 (0) 9 761 8007

Cell: +972 (0) 52 7335999

Fax: +972 (0) 9 746 7901

E-mail: jonathan@xxxxxxxxxxxxx

Web: www.panayainc.com

 

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