On Thu, Mar 26, 2015 at 10:07:21PM -0700, Jason Low wrote: >On Fri, 2015-03-27 at 10:12 +0800, Wanpeng Li wrote: >> Hi Preeti, >> On Thu, Mar 26, 2015 at 06:32:44PM +0530, Preeti U Murthy wrote: >> > >> >1. An ILB CPU was chosen from the first numa domain to trigger nohz idle >> >load balancing [Given the experiment, upto 6 CPUs per core could be >> >potentially idle in this domain.] >> > >> >2. However the ILB CPU would call load_balance() on itself before >> >initiating nohz idle load balancing. >> > >> >3. Given cores are SMT8, the ILB CPU had enough opportunities to pull >> >tasks from its sibling cores to even out load. >> > >> >4. Now that the ILB CPU was no longer idle, it would abort nohz idle >> >load balancing >> >> I don't see abort nohz idle load balancing when ILB CPU was no longer idle >> in nohz_idle_balance(), could you explain more in details? > >Hi Wanpeng, > >In nohz_idle_balance(), there is a check for need_resched() so if the >cpu has something to run, it should exit nohz_idle_balance(), which may >cause it to not do the idle balancing on the other CPUs.
Got it, thanks. ;) Regards, Wanpeng Li > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/