diff options
Diffstat (limited to 'meta-eas/recipes-kernel/linux/linux-renesas/0005-sched-fair-Avoid-pulling-tasks-from-non-overloaded-h.patch')
| -rw-r--r-- | meta-eas/recipes-kernel/linux/linux-renesas/0005-sched-fair-Avoid-pulling-tasks-from-non-overloaded-h.patch | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/meta-eas/recipes-kernel/linux/linux-renesas/0005-sched-fair-Avoid-pulling-tasks-from-non-overloaded-h.patch b/meta-eas/recipes-kernel/linux/linux-renesas/0005-sched-fair-Avoid-pulling-tasks-from-non-overloaded-h.patch new file mode 100644 index 0000000..d4bd2bd --- /dev/null +++ b/meta-eas/recipes-kernel/linux/linux-renesas/0005-sched-fair-Avoid-pulling-tasks-from-non-overloaded-h.patch @@ -0,0 +1,81 @@ +From 3a86f1d4b2d288f765534c1763ed698029376098 Mon Sep 17 00:00:00 2001 +From: Morten Rasmussen <morten.rasmussen@arm.com> +Date: Fri, 14 Oct 2016 14:41:10 +0100 +Subject: [PATCH 05/92] sched/fair: Avoid pulling tasks from non-overloaded + higher capacity groups + +For asymmetric CPU capacity systems it is counter-productive for +throughput if low capacity CPUs are pulling tasks from non-overloaded +CPUs with higher capacity. The assumption is that higher CPU capacity is +preferred over running alone in a group with lower CPU capacity. + +This patch rejects higher CPU capacity groups with one or less task per +CPU as potential busiest group which could otherwise lead to a series of +failing load-balancing attempts leading to a force-migration. + +Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> +Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Thomas Gleixner <tglx@linutronix.de> +Cc: dietmar.eggemann@arm.com +Cc: freedom.tan@mediatek.com +Cc: keita.kobayashi.ym@renesas.com +Cc: mgalbraith@suse.de +Cc: sgurrappadi@nvidia.com +Cc: vincent.guittot@linaro.org +Cc: yuyang.du@intel.com +Link: http://lkml.kernel.org/r/1476452472-24740-5-git-send-email-morten.rasmussen@arm.com +Signed-off-by: Ingo Molnar <mingo@kernel.org> +(cherry picked from commit 9e0994c0a1c1f82c705f1f66388e1bcffcee8bb9) +Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com> +--- + kernel/sched/fair.c | 25 +++++++++++++++++++++++++ + 1 file changed, 25 insertions(+) + +diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c +index faf8f18..ee39bfd 100644 +--- a/kernel/sched/fair.c ++++ b/kernel/sched/fair.c +@@ -7073,6 +7073,17 @@ static inline int sg_imbalanced(struct sched_group *group) + return false; + } + ++/* ++ * group_smaller_cpu_capacity: Returns true if sched_group sg has smaller ++ * per-CPU capacity than sched_group ref. ++ */ ++static inline bool ++group_smaller_cpu_capacity(struct sched_group *sg, struct sched_group *ref) ++{ ++ return sg->sgc->min_capacity * capacity_margin < ++ ref->sgc->min_capacity * 1024; ++} ++ + static inline enum + group_type group_classify(struct sched_group *group, + struct sg_lb_stats *sgs) +@@ -7176,6 +7187,20 @@ static bool update_sd_pick_busiest(struct lb_env *env, + if (sgs->avg_load <= busiest->avg_load) + return false; + ++ if (!(env->sd->flags & SD_ASYM_CPUCAPACITY)) ++ goto asym_packing; ++ ++ /* ++ * Candidate sg has no more than one task per CPU and ++ * has higher per-CPU capacity. Migrating tasks to less ++ * capable CPUs may harm throughput. Maximize throughput, ++ * power/energy consequences are not considered. ++ */ ++ if (sgs->sum_nr_running <= sgs->group_weight && ++ group_smaller_cpu_capacity(sds->local, sg)) ++ return false; ++ ++asym_packing: + /* This is the busiest node in its class. */ + if (!(env->sd->flags & SD_ASYM_PACKING)) + return true; +-- +1.9.1 + |