* Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> [2005-10-20 05:39]:
>
> On 19 Oct 2005, at 23:45, Ryan Harper wrote:
>
> >This patch modifies the lowlevel xc vcpuinfo call to convert a vcpu's
> >cpumap to a list of int. XendDomainInfo.py filters the cpumap into a
> >smaller list that is bound by the number of vcpus allocated to a
> >domain.
>
> Two things:
>
> First, there is no correspondence between size of cpumap and
> max_vcpu_id, because there is no direct relationship between sizes of
> virtual and physical CPU spaces. We could have a system with more vcpus
> than physical cpus, or vice versa. And cpumap represents sets of
> physical cpus, not sets of virtual cpus.
Right. I was carrying through the previous incorrect behavior:
cpumap = sxp.child_value(info, 'cpumap', [])
mask = ((int(sxp.child_value(info, 'vcpus', '0')))**2) - 1
>
> Second, I meant that the cpumap list should contain just the list of
> physical cpus that that vcpu can run on. So, for example, a cpumap
> bitmask of 0x5 would correspond to the cpumap list [0, 2], not the list
> [0, -1, 2, -1, -1, ...]. The latter is a weird and redundant
> representation.
OK. That was my poor hack around python/c blowing up if you didn't fill
out every spot in the list you created. I'm going to switch to using
PyList_Append() rather than creating the list size up front.
Are you interested in any modification of the cpumap to list conversion?
Or is it ok if vcpu-list shows a long list of integers?
I would think mapping cpu % nr_cpus, throwing away duplicates would be
best. With [0,1,2,3] and nr_cpus=2, cpumap would be [0,1].
--
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253 T/L: 678-9253
ryanh@xxxxxxxxxx
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