diff options
Diffstat (limited to 'meta-eas/recipes-kernel/linux/linux-renesas/0003-sched-fair-Consider-spare-capacity-in-find_idlest_gr.patch')
| -rw-r--r-- | meta-eas/recipes-kernel/linux/linux-renesas/0003-sched-fair-Consider-spare-capacity-in-find_idlest_gr.patch | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/meta-eas/recipes-kernel/linux/linux-renesas/0003-sched-fair-Consider-spare-capacity-in-find_idlest_gr.patch b/meta-eas/recipes-kernel/linux/linux-renesas/0003-sched-fair-Consider-spare-capacity-in-find_idlest_gr.patch new file mode 100644 index 0000000..674ebb9 --- /dev/null +++ b/meta-eas/recipes-kernel/linux/linux-renesas/0003-sched-fair-Consider-spare-capacity-in-find_idlest_gr.patch @@ -0,0 +1,140 @@ +From 575af3de702dae80c40bf510aaf7755374accb88 Mon Sep 17 00:00:00 2001 +From: Morten Rasmussen <morten.rasmussen@arm.com> +Date: Fri, 14 Oct 2016 14:41:08 +0100 +Subject: [PATCH 03/92] sched/fair: Consider spare capacity in + find_idlest_group() + +In low-utilization scenarios comparing relative loads in +find_idlest_group() doesn't always lead to the most optimum choice. +Systems with groups containing different numbers of cpus and/or cpus of +different compute capacity are significantly better off when considering +spare capacity rather than relative load in those scenarios. + +In addition to existing load based search an alternative spare capacity +based candidate sched_group is found and selected instead if sufficient +spare capacity exists. If not, existing behaviour is preserved. + +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/1476452472-24740-3-git-send-email-morten.rasmussen@arm.com +Signed-off-by: Ingo Molnar <mingo@kernel.org> +(cherry picked from commit 6a0b19c0f39a7a7b7fb77d3867a733136ff059a3) +Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com> +--- + kernel/sched/fair.c | 50 +++++++++++++++++++++++++++++++++++++++++++++----- + 1 file changed, 45 insertions(+), 5 deletions(-) + +diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c +index b05d691..1ad3706 100644 +--- a/kernel/sched/fair.c ++++ b/kernel/sched/fair.c +@@ -5202,6 +5202,14 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, + return 1; + } + ++static inline int task_util(struct task_struct *p); ++static int cpu_util_wake(int cpu, struct task_struct *p); ++ ++static unsigned long capacity_spare_wake(int cpu, struct task_struct *p) ++{ ++ return capacity_orig_of(cpu) - cpu_util_wake(cpu, p); ++} ++ + /* + * find_idlest_group finds and returns the least busy CPU group within the + * domain. +@@ -5211,7 +5219,9 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, + int this_cpu, int sd_flag) + { + struct sched_group *idlest = NULL, *group = sd->groups; ++ struct sched_group *most_spare_sg = NULL; + unsigned long min_load = ULONG_MAX, this_load = 0; ++ unsigned long most_spare = 0, this_spare = 0; + int load_idx = sd->forkexec_idx; + int imbalance = 100 + (sd->imbalance_pct-100)/2; + +@@ -5219,7 +5229,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, + load_idx = sd->wake_idx; + + do { +- unsigned long load, avg_load; ++ unsigned long load, avg_load, spare_cap, max_spare_cap; + int local_group; + int i; + +@@ -5231,8 +5241,12 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, + local_group = cpumask_test_cpu(this_cpu, + sched_group_cpus(group)); + +- /* Tally up the load of all CPUs in the group */ ++ /* ++ * Tally up the load of all CPUs in the group and find ++ * the group containing the CPU with most spare capacity. ++ */ + avg_load = 0; ++ max_spare_cap = 0; + + for_each_cpu(i, sched_group_cpus(group)) { + /* Bias balancing toward cpus of our domain */ +@@ -5242,6 +5256,11 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, + load = target_load(i, load_idx); + + avg_load += load; ++ ++ spare_cap = capacity_spare_wake(i, p); ++ ++ if (spare_cap > max_spare_cap) ++ max_spare_cap = spare_cap; + } + + /* Adjust by relative CPU capacity of the group */ +@@ -5249,12 +5268,33 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, + + if (local_group) { + this_load = avg_load; +- } else if (avg_load < min_load) { +- min_load = avg_load; +- idlest = group; ++ this_spare = max_spare_cap; ++ } else { ++ if (avg_load < min_load) { ++ min_load = avg_load; ++ idlest = group; ++ } ++ ++ if (most_spare < max_spare_cap) { ++ most_spare = max_spare_cap; ++ most_spare_sg = group; ++ } + } + } while (group = group->next, group != sd->groups); + ++ /* ++ * The cross-over point between using spare capacity or least load ++ * is too conservative for high utilization tasks on partially ++ * utilized systems if we require spare_capacity > task_util(p), ++ * so we allow for some task stuffing by using ++ * spare_capacity > task_util(p)/2. ++ */ ++ if (this_spare > task_util(p) / 2 && ++ imbalance*this_spare > 100*most_spare) ++ return NULL; ++ else if (most_spare > task_util(p) / 2) ++ return most_spare_sg; ++ + if (!idlest || 100*this_load < imbalance*min_load) + return NULL; + return idlest; +-- +1.9.1 + |