Messages in this thread |  | | | Date | Fri, 06 Feb 2004 10:39:31 -0800 | | From | "Martin J. Bligh" <> | | Subject | Re: [PATCH] Load balancing problem in 2.6.2-mm1 |
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> 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.
M.
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