diff options
| author | Vincent Guittot <vincent.guittot@linaro.org> | 2019-07-24 16:30:40 +0200 |
|---|---|---|
| committer | Vincent Guittot <vincent.guittot@linaro.org> | 2019-10-14 09:14:43 +0200 |
| commit | aa6e63fe3ff26f2c32e989cc7fa5a5ee1c069c24 (patch) | |
| tree | d1ba9634601c36f0808af345caa22cc493ca420d | |
| parent | 03b29a8b539644189882a244bbcabbaf4b44cc6a (diff) | |
sched/fair: evenly spread tasks when not overloaded
When there is only 1 cpu per group, using the idle cpus to evenly spread
tasks doesn't make sense and nr_running is a better metrics.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
| -rw-r--r-- | kernel/sched/fair.c | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9ac226428952..9b8e20de22f8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8601,18 +8601,34 @@ static struct sched_group *find_busiest_group(struct lb_env *env) busiest->sum_nr_running > local->sum_nr_running + 1) goto force_balance; - if (busiest->group_type != group_overloaded && - (env->idle == CPU_NOT_IDLE || - local->idle_cpus <= (busiest->idle_cpus + 1))) - /* - * If the busiest group is not overloaded - * and there is no imbalance between this and busiest group - * wrt idle CPUs, it is balanced. The imbalance - * becomes significant if the diff is greater than 1 otherwise - * we might end up to just move the imbalance on another - * group. - */ - goto out_balanced; + if (busiest->group_type != group_overloaded) { + if (env->idle == CPU_NOT_IDLE) + /* + * If the busiest group is not overloaded (and as a + * result the local one too) but this cpu is already + * busy, let another idle cpu try to pull task. + */ + goto out_balanced; + + if (busiest->group_weight > 1 && + local->idle_cpus <= (busiest->idle_cpus + 1)) + /* + * If the busiest group is not overloaded + * and there is no imbalance between this and busiest + * group wrt idle CPUs, it is balanced. The imbalance + * becomes significant if the diff is greater than 1 + * otherwise we might end up to just move the imbalance + * on another group. Of course this applies only if + * there is more than 1 CPU per group. + */ + goto out_balanced; + + if (busiest->sum_h_nr_running == 1) + /* + * busiest doesn't have any tasks waiting to run + */ + goto out_balanced; + } force_balance: /* Looks like there is an imbalance. Compute it */ |