VCPU affinity

VCPU affinity

[Ky Srinivasan]

What is the best way to pin VCPUs. It looks like the implementation of affinity currently  is at best  only "soft". 

Regards,

K. Y

Re: VCPU affinity

[Emmanuel Ackaouy]

On Dec 18, 2006, at 16:56, Ky Srinivasan wrote:
> What is the best way to pin VCPUs. It looks like the implementation of 
> affinity currently  is at best  only "soft".
>
> Regards,

VCPU affinity should not be soft. By the time the set affinity hypercall
returns, the VCPU in question should be running on a physical CPU
set in its affinity mask.

If it's not behaving this way then something is broken. Can you send
more details?

Re: VCPU affinity

[Ky Srinivasan]

I am chasing a bug we seem to be hitting where we are not able to specify the binding; will let you know once I know more.

Regards,

K. Y

>>> On Mon, Dec 18, 2006 at 11:01 AM, in message
<0951ba397e5752bf7a54f5ecaf67ad4e@gmail.com>, Emmanuel Ackaouy
<ackaouy@gmail.com> wrote: 
> On Dec 18, 2006, at 16:56, Ky Srinivasan wrote:
>> What is the best way to pin VCPUs. It looks like the implementation of 
>> affinity currently  is at best  only "soft".
>>
>> Regards,
> 
> VCPU affinity should not be soft. By the time the set affinity hypercall
> returns, the VCPU in question should be running on a physical CPU
> set in its affinity mask.
> 
> If it's not behaving this way then something is broken. Can you send
> more details?

Re: VCPU affinity

[Keir Fraser]

VCPUs will run only on CPUs in their affinity mask. If you want to pin to a
particular CPU then specify an affinity mask with only that CPU contained in
it.

 -- Keir


On 18/12/06 15:56, "Ky Srinivasan" <ksrinivasan@novell.com> wrote:

> What is the best way to pin VCPUs. It looks like the implementation of
> affinity currently  is at best  only "soft".
> 
> Regards,
> 
> K. Y
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: VCPU affinity

[Ky Srinivasan]

Kier,

Looks like we may have a problem in our tool stack. If I pin the VCPUs from the command line, VCPUs stay bound to the specified physical processors. However, if the binding is specified in the VM config file, it does not work. Looks like we are not correctly handling the CPU affinity information. Will keep you posted once I learn more.

Regards,

K. Y

>>> On Mon, Dec 18, 2006 at 11:05 AM, in message
<C1AC6CC0.6429%keir@xensource.com>, Keir Fraser <keir@xensource.com> wrote: 
> VCPUs will run only on CPUs in their affinity mask. If you want to pin to a
> particular CPU then specify an affinity mask with only that CPU contained in
> it.
> 
>  --  Keir
> 
> 
> On 18/12/06 15:56, "Ky Srinivasan" <ksrinivasan@novell.com> wrote:
> 
>> What is the best way to pin VCPUs. It looks like the implementation of
>> affinity currently  is at best  only "soft".
>> 
>> Regards,
>> 
>> K. Y
>> 
>> 
>> _______________________________________________
>> Xen- devel mailing list
>> Xen- devel@lists.xensource.com
>> http://lists.xensource.com/xen- devel
> 
> 
> _______________________________________________
> Xen- devel mailing list
> Xen- devel@lists.xensource.com
> http://lists.xensource.com/xen- devel