Re: [Xen-devel] Problems about CPU Affinity

Ryan Harper
Fri, 18 May 2007 15:07:46 -0000

* Ian Pratt <Ian.Pratt@cl.cam.ac.uk> [2007-05-18
05:36]:
> > > I thought you could by specifying a list of physical CPUs?
> > > Perhaps this
> > > got broken by the xapi changes?
> >
> > No, the problem that the original post talks about, is that you
can''t
> > set affinity of individual VCPU''s to individual
PCPU''s, e.g:
> > vcpus=2
> > cpus=2
>
> AFAIK, you used to be able to specify a list:
>  vcpus=2
>  cpus = ["2,3,4","5,6,7"]
>
> Maybe this patch never went in. AFAIR it was from Ryan.

I don''t think we ever took the multi cpumask per vcpu patch.  At the
time, only the part where we apply the same cpumask defined from
cpus=""
value to each vcpu when in allowing the credit scheduler to balance within
the affinity mask.

Couple of threads of discussion here:

http://lists.xensource.com/archives/html/xen-devel/2006-08/msg00965.html

follow up threads:

http://lists.xensource.com/archives/html/xen-devel/2006-08/msg00783.html
http://lists.xensource.com/archives/html/xen-devel/2006-08/msg00785.html

The only changes that is see committed were:

changeset:   11111:438ed1c4b391
user:        kfraser@localhost.localdomain
date:        Tue Aug 15 10:56:59 2006 +0100
summary:     [XEND] Apply the domain cpumask fully to every vcpu in the domain.


--
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253
ryanh@us.ibm.com