Messages in this thread | | | Date | Wed, 28 Sep 2011 19:47:01 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: [PATCH v1] sched: fix nohz idle load balancer issues |
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* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> [2011-09-28 10:04:27]:
> > Especially with higher number of logical CPUs. Likely cleaner way is to clear > > first_pick, second_pick on idle instead of clearing on tickless. > > I think I tried that (cleared first/second_pick_cpu in > nohz_kick_needed() upon idle) but didn't get the best results. Let me > try that again and post idle time numbers.
So made some changes so that first/second_pick_cpu identifiers are cleared when corresponding cpus become idle. They are cleared in pick_next_task_idle() ..
With that change, I don't see additional benefit of having a third busy cpu kick ilb_cpu when it has > 1 task.
Idle time -> Avg. Std.Dev Min Max W/o third busy cpu kicking 4.57% 0.9 3% 8% With third busy cpu kicking 4.78% 1.1% 3% 8%
So will go with your suggestion in the next version!
- vatsa
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