RE: Setup an IA64 specific reclaim distance

From: Christoph Lameter <clameter_at_sgi.com>
Date: 2006-04-15 02:44:58
On Fri, 14 Apr 2006, Luck, Tony wrote:

> > We found that on motherboard latencies are typically 1 to 1.4 of local memory
> > access speed whereas multinode systems which benefit from zone reclaim have
> > usually more than 1.5 times the latency of a local access.
> > 
> > Set the reclaim distance for IA64 to 1.5 times.
> 
> Does this really apply just to ia64 systems?  Or is the "20" value in
> topology.h just wrong?

The value in topology.h is the same as the REMOTE_DISTANCE. I think we 
better leave these as fallbacks for systems that do not implement 
node_distance().

> Is the right value for this any any way related to the "migration_cost"
> that we spend many seconds of boot time computing?

I am not familiar with that. Does the migration_cost take the 
SLIT node distances into consideration?

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Received on Sat Apr 15 02:45:41 2006

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