On Wed, Feb 04, 2015 at 06:31:21PM +0000, Morten Rasmussen wrote: > From: Dietmar Eggemann <dietmar.eggem...@arm.com> > > Energy-aware load balancing bases on cpu usage so the upper bound of its > operational range is a fully utilized cpu. Above this tipping point it > makes more sense to use weighted_cpuload to preserve smp_nice. > This patch implements the tipping point detection in update_sg_lb_stats > as if one cpu is over-utilized the current energy-aware load balance > operation will fall back into the conventional weighted load based one. > > cc: Ingo Molnar <mi...@redhat.com> > cc: Peter Zijlstra <pet...@infradead.org> > > Signed-off-by: Dietmar Eggemann <dietmar.eggem...@arm.com> > --- > kernel/sched/fair.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 6b79603..4849bad 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6723,6 +6723,10 @@ static inline void update_sg_lb_stats(struct lb_env > *env, > sgs->sum_weighted_load += weighted_cpuload(i); > if (idle_cpu(i)) > sgs->idle_cpus++; > + > + /* If cpu is over-utilized, bail out of ea */ > + if (env->use_ea && cpu_overutilized(i, env->sd)) > + env->use_ea = false; > }
I don't immediately see why this is desired. Why would a single overloaded CPU be reason to quit? It could be the cpus simply aren't 'balanced' right and the group as a whole is still under utilized. In that case we want to continue the balance pass to reach this equilibrium. -- 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/
