Messages in this thread | | | Date | Mon, 25 Aug 2003 10:38:27 -0700 | From | "Martin J. Bligh" <> | Subject | Re: [patch 2.6.0t4] 1 cpu/node scheduler fix |
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> This is the 1 cpu/node fix of the NUMA scheduler rewritten for the new > cpumask handling. The previous version was a bit too aggressive with > cross node balancing so I changed the default timings a bit such that > the behavior is very similar to the old one. > > Here is what the patch does: > - Links the frequency of cross-node balances to the number of failed > local balance attempts. This simplifies the code by removing the too > rigid cross-node balancing dependency of the timer interrupts. > > - Fixes the 1 CPU/node issue, i.e. eliminates local balance attempts > for the nodes which have only one CPU. Can happen on any NUMA > platform (playing around with a 2 CPU/node box and have a flaky CPU, > so I have sometimes a node with only one CPU), is a major issue on > AMD64. > > - Makes the cross-node balance frequency tunable by the parameter > NUMA_FACTOR_BONUS. Its default setting is such that the scheduler > behaves like before: cross node balance every 5 local node balances on > an idle CPU, every 2 local node balances on a busy CPU. This parameter > should be tuned for each platform depending on its NUMA factor.
This seems to clear up the low end stuff I was seeing before - thanks.
Did you (or anyone else) get a chance to test this on AMD? Would be nice to confirm that's fixed ...
M.
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