On 27 August 2015 at 18:50, Jason Low <[email protected]> wrote: > On Thu, 2015-08-27 at 13:21 +0200, Vincent Guittot wrote: >> Hi, >> >> On 3 August 2015 at 11:55, Vincent Guittot <[email protected]> >> wrote: >> > Since commit d4573c3e1c99 ("sched: Improve load balancing in the presence >> > of idle CPUs"), the ILB CPU starts with the idle load balancing of other >> > idle CPUs and finishes with itself in order to speed up the spread of tasks >> > in all idle CPUs. >> > >> > The this_rq->next_balance is still used in nohz_idle_balance as an >> > intermediate step to gather the shortest next balance before updating >> > nohz.next_balance. But the former has not been updated yet and is likely to >> > be set with the current jiffies. As a result, the nohz.next_balance will be >> > set with current jiffies instead of the real next balance date. This >> > generates spurious kicks of nohz ilde balance. >> > >> > nohz_idle_balance must set the nohz.next_balance without taking into >> > account this_rq->next_balance which is not updated yet. Then, this_rq will >> > update nohz.next_update with its next_balance once updated and if >> > necessary. >> > >> > Signed-off-by: Vincent Guittot <[email protected]> > > Acked-by: Jason Low <[email protected]>
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