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Martin J. Bligh wrote: >> Good stuff, I just gave the patch a spin and things seem a little >> calmer. However Im still seeing a lot of balancing going on within a >> node. >> >>This is a clearly recognizable edge case, so I'll try drawing this up on >>some paper and see if I can suggest another patch. There's no good reason >>to move one lone process from a particular processor to another idle one. >> >>But it also approaches a question that's come up before: if you have 2 >>tasks on processor A and 1 on processor B, do you move one from A to B? >>One argument is that the two tasks on A will take twice as long as >>the one on B if you do nothing. But another says that bouncing a task >>around can't correct the overall imbalance and so is wasteful. I know >>of benchmarks where both behaviors are considered important. Thoughts? >> > >It's the classic fairness vs throughput thing we've argued about before. >Most workloads don't have that static a number of processes, but it >probably does need to do it if the imbalance is persistent ... but much >more reluctantly than normal balancing. See the patch I sent out a bit >earlier to test it - that may be *too* extreme in the other direction, >but it should confirm what's going on, at least. > > Yep. I've argued for fairness here, and that is presently what we get. Between nodes the threshold should probably be higher though. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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