On 21/09/20 08:24, Vincent Guittot wrote: > sched domains tend to trigger simultaneously the load balance loop but > the larger domains often need more time to collect statistics. This > slowness makes the larger domain trying to detach tasks from a rq whereas > tasks already migrated somewhere else at a sub-domain level. This is not > a real problem for idle LB because the period of smaller domains will > increase with its CPUs being busy and this will let time for higher ones > to pulled tasks. But this becomes a problem when all CPUs are already busy > because all domains stay synced when they trigger their LB. > > A simple way to minimize simultaneous LB of all domains is to decrement the > the busy interval by 1 jiffies. Because of the busy_factor, the interval of > larger domain will not be a multiple of smaller ones anymore. > > Reviewed-by: Phil Auld <pa...@redhat.com> > Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org>
Reviewed-by: Valentin Schneider <valentin.schnei...@arm.com>
