Messages in this thread | | | Date | Sat, 07 Feb 2004 09:48:45 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH] Load balancing problem in 2.6.2-mm1 |
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Rick Lindsley wrote:
> Yep. I've argued for fairness here, and that is presently what > we get. Between nodes the threshold should probably be higher > though. > >While I like the idea of a self-tuning scheduler, when combined with >this new sched_domain algorithm it's hard to tell if the tuning or the >algorithm is at fault when we get results we don't like. Have you done >much running with the auto-tuning turned off, using the old values, >to see the impact (positive or negative) that just the new algorithm has? > >
I'm not sure what you mean by self-tuning. Do you mean the scheduling backoff stuff? Because that makes very little difference on a 16-way NUMAQ. However it becomes critical for SGI above around 128 CPUs IIRC so I just kept it in mind when doing sched domains.
The new balancing calculations are definitely a win in my tests. One tiny regression (the order of 1%) I saw on the NUMAQ was tbench due to increased idle time. But I'll still take it as a win because we were doing nearly 1000 times less inter node balancing.
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