Re: [Xen-devel] Re: NUMA and SMP

[Daniel Stodden <stodden@xxxxxxxxxx>]

On Thu, 2007-03-22 at 10:12 -0500, Ryan Harper wrote:
> * Daniel Stodden <stodden@xxxxxxxxxx> [2007-03-22 10:03]:
> > On Thu, 2007-03-22 at 08:02 -0500, Ryan Harper wrote:
> > 
> > > > > and for the paravirt xen-guest-linux do not support  numa-aware  now 
> > > > > ,or 
> > > > > does it  support  numa-aware  if CONFIG_NUMA choiced?
> > > > 
> > > > no. there is num-support in xen, as far as inspection of the memory
> > > > topology and inclusion in the memory management is concerned. so
> > > > basically, you can add the desired node number to get_free_pages().
> > > 
> > > There is NUMA support in Xen since 3.0.4 in the hypervisor, and we have
> > > the capability to ensure a guest memory is local to the processors being
> > > used.  The topology of the system is not exported to the guest so
> > > CONFIG_NUMA in the guest kernel config will be of no value.
> > 
> > oops, that's more than i've noticed. thanks for the correction. so now
> > it seems up to me to ask questions. :} i don't see that path taken along
> > vcpu_migrate. where is it happening?
> 
> The credit scheduler is not NUMA aware.  So to ensure that the initial
> allocation for the guest remains local, the domain uses a cpumask
> (generated from cpus="" config file option)  to keep the scheduler from
> migrating vcpus to off-node cpus.

i see. not like i'm too deep in the srat, but methinks there may be sane
default values to be generated from the srat. any work happening or
having happened on that front?

regards,
daniel

-- 
Daniel Stodden
LRR     -      Lehrstuhl für Rechnertechnik und Rechnerorganisation
Institut für Informatik der TU München             D-85748 Garching
http://www.lrr.in.tum.de/~stodden         mailto:stodden@xxxxxxxxxx
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