[et-mgmt-tools] Re: [PATCH] Add virt-install option to auto choose cpuset value (NUMA)

[Beth Kon]

On Mon, 2008-03-24 at 11:54 -0400, Cole Robinson wrote:
> Ryan Harper wrote:
> > * Cole Robinson <crobinso at redhat.com> [2008-03-14 14:50]:
> >> The patch below adds an option to virt-install to auto choose
> >> physical cpu pinning based on available memory on a NUMA machine.
> >> Conceivably this could be expanded in the future to auto choose
> >> by some other metric as well, but for now only a NUMA setup is
> >> implemented.
> >>
> >> Using --cpuset=auto will create a traditional cpuset argument
> >> using all the cpus associated with the cell that best fits the
> >> requested guest memory.
> >>
> >> The only question I have for those interested: Is best fit an 
> >> appropriate default choice? should there be a way to choose 
> >> another scheme (i.e. worst fit)?
> > Cole,
> > 
> > Thanks for the patch, looks good.  I believe best fit is a good choice.
> > For our NUMA systems, we want to fully utilize a single node before
> > moving work to a second node as to minimize the amount of memory traffic
> > over the interconnects.  Best-fit should do this by selecting cell with
> > the least amount of free ram that satisfies the request.
> > 
> 
> This is committed now:
> 
> http://hg.et.redhat.com/virt/applications/virtinst--devel?cs=847863a0c075
> 
> The committed patch fixes what would have been a regression when no cpuset
> was specified, so be sure to use the upstream patch rather than the one
> I initially posted.
> 
> Thanks,
> Cole
> 
> 
Sorry if an append appears multiple times... I tried to respond via
gmane (which I'm new to) and it doesn't appear to have made it. My
comment was that it would be better not to fail if the box is found to
be non-NUMA. Seems preferable to just treat that as an effective noop
and not specify a cpuset. This would allow the same command line to work
regardless of whether the box is NUMA or not.

> 
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-- 
Elizabeth Kon (Beth)
IBM Linux Technology Center
Open Hypervisor Team
email: eak at us.ibm.com