Re: Re: NUMA and SMP

[Ryan Harper <ryanh@us.ibm.com>]

* Daniel Stodden <stodden@cs.tum.edu> [2007-03-22 07:29]:
> On Thu, 2007-03-22 at 20:13 +0800, tgh wrote:
> > Thank you for your reply
> > 
> > 
> > 
> > >   
> > >> in the smp with adm64 with the hardware of numa, its linux is a smp os 
> > >> ,then there is only one node (struct pglist_data) in the os when running 
> > >> or  there are as many nodes as cpus in the system,  does linux smp 
> > >> support two or more nodes when running? or in this case linux support 
> > >> numa feature?
> > >>     
> > >
> > > the number of nodes corresponds to the number of memory areas which
> > > allocators need distinguish. in the case of integrated memory
> > > controllers like amd64, expect to find as many nodes as there are
> > > processors. 
> > >
> > > yes, linux has numa support. see linux/Documentation/vm/
> > >   
> > 
> > linux has numa support,and in the case of integrated memory controllers 
> > like amd64, CONFIG_NUMA should be choice and linux support numa,is it 
> > right? if CONFIG_NUMA is not choice ,then linux could not work well in 
> > the case of integrated memory controllers even for amd64,is it right? 
> 
> 
> > 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.


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