Messages in this thread | | | Date | Wed, 19 Feb 2014 10:19:59 +0100 | From | Michal Hocko <> | Subject | Re: ppc: RECLAIM_DISTANCE 10? |
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On Wed 19-02-14 00:20:21, David Rientjes wrote: > On Wed, 19 Feb 2014, Michal Hocko wrote: > > > > I strongly suspect that the patch is correct since powerpc node distances > > > are different than the architectures you're talking about and get doubled > > > for every NUMA domain that the hardware supports. > > > > Even if the units of the distance is different on PPC should every NUMA > > machine have zone_reclaim enabled? That doesn't right to me. > > > > In my experience on powerpc it's very correct, there's typically a > significant latency in remote access and we don't have the benefit of a > SLIT that actually defines the locality between proximity domains like we > do on other architectures.
Interesting. So is the PPC NUMA basically about local vs. very distant? Should REMOTE_DISTANCE reflect that as well? Or can we have distance < REMOTE_DISTANCE and it would still make sense to have zone_reclaim enabled?
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Thanks! -- Michal Hocko SUSE Labs
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