Messages in this thread | | | From | "Chen, Kenneth W" <> | Subject | RE: + sched-use-tasklet-to-call-balancing.patch added to -mm tree | Date | Thu, 9 Nov 2006 22:18:13 -0800 |
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Christoph Lameter wrote on Tuesday, November 07, 2006 1:50 PM > On Tue, 7 Nov 2006, Chen, Kenneth W wrote: > > > What broke the system was the disabling of interrupts over long time > > > periods during load balancing. > > The previous global load balancing tasket could be an interesting data point. > > Yup seems also very interesting to me. We could drop the staggering code > f.e. if we would leave the patch as is. Maybe there are other ways to > optimize the code because we know that there are no concurrent > balance_tick() functions running. > > > Do you see a lot of imbalance in the system with the global tasket? Does it > > take prolonged interval to reach balanced system from imbalance? > > I am rather surprised that I did not see any problems but I think we would > need some more testing. It seems that having only one load balance > running at one time speeds up load balacing in general since there is > less lock contention.
I ran majority of micro-benchmarks from LKP project with global load balance tasklet. (http://kernel-perf.sourceforge.net)
Result is here: http://kernel-perf.sourceforge.net/sched/global-load-bal.txt
All results are within noise range. The global tasklet does a fairly good job especially on context switch intensive workload like aim7, volanomark, tbench etc. Note all machines are non-numa platform.
Base on the data, I think we should make the load balance tasklet one per numa node instead of one per CPU.
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