| From | Morten Rasmussen <> | Subject | [RFCv5 PATCH 34/46] sched: Enable idle balance to pull single task towards cpu with higher capacity | Date | Tue, 7 Jul 2015 19:24:17 +0100 |
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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
We do not want to miss out on the ability to pull a single remaining task from a potential source cpu towards an idle destination cpu if the energy aware system operates above the tipping point.
Add an extra criteria to need_active_balance() to kick off active load balance if the source cpu is over-utilized and has lower capacity than the destination cpu.
cc: Ingo Molnar <mingo@redhat.com> cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> --- kernel/sched/fair.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 48ecf02..97eb83e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7569,6 +7569,13 @@ static int need_active_balance(struct lb_env *env) return 1; } + if ((capacity_of(env->src_cpu) < capacity_of(env->dst_cpu)) && + env->src_rq->cfs.h_nr_running == 1 && + cpu_overutilized(env->src_cpu) && + !cpu_overutilized(env->dst_cpu)) { + return 1; + } + return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); } @@ -7923,7 +7930,8 @@ static int idle_balance(struct rq *this_rq) this_rq->idle_stamp = rq_clock(this_rq); if (this_rq->avg_idle < sysctl_sched_migration_cost || - !this_rq->rd->overload) { + (!energy_aware() && !this_rq->rd->overload) || + (energy_aware() && !this_rq->rd->overutilized)) { rcu_read_lock(); sd = rcu_dereference_check_sched_domain(this_rq->sd); if (sd) -- 1.9.1
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