Commit-ID: b37d931685b519cd61a67fbdfe5b04707eb76e32 Gitweb: http://git.kernel.org/tip/b37d931685b519cd61a67fbdfe5b04707eb76e32 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Wed, 28 Aug 2013 11:50:34 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 12 Sep 2013 19:14:44 +0200
sched/fair: Rework and comment the group_capacity code Pull out the group_capacity computation so that we can more clearly comment its issues. Signed-off-by: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/n/tip-az1hl1ya55k361nkeh9bj...@git.kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/sched/fair.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index baba313..218f9c5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4553,6 +4553,27 @@ static inline int sg_imbalanced(struct sched_group *group) return group->sgp->imbalance; } +/* + * Compute the group capacity. + * + * For now the capacity is simply the number of power units in the group_power. + * A power unit represents a full core. + * + * This has an issue where N*frac(smt_power) >= 1, in that case we'll see extra + * 'cores' that aren't actually there. + */ +static inline int sg_capacity(struct lb_env *env, struct sched_group *group) +{ + + unsigned int power = group->sgp->power; + unsigned int capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE); + + if (!capacity) + capacity = fix_small_capacity(env->sd, group); + + return capacity; +} + /** * update_sg_lb_stats - Update sched_group's statistics for load balancing. * @env: The load balancing environment. @@ -4596,16 +4617,11 @@ static inline void update_sg_lb_stats(struct lb_env *env, if (sgs->sum_nr_running) sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; - sgs->group_imb = sg_imbalanced(group); - - sgs->group_capacity = - DIV_ROUND_CLOSEST(sgs->group_power, SCHED_POWER_SCALE); - - if (!sgs->group_capacity) - sgs->group_capacity = fix_small_capacity(env->sd, group); - sgs->group_weight = group->group_weight; + sgs->group_imb = sg_imbalanced(group); + sgs->group_capacity = sg_capacity(env, group); + if (sgs->group_capacity > sgs->sum_nr_running) sgs->group_has_capacity = 1; } -- 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/
