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authorFrode Isaksen <fisaksen@baylibre.com>2017-12-19 11:15:35 +0000
committerJan-Simon Moeller <jsmoeller@linuxfoundation.org>2018-02-07 11:47:29 +0000
commitc4a6287185179732dfc1e903c195ff90c19f1065 (patch)
treed35f5010dbd952e40f5c178322026445b55757c1 /meta-eas/recipes-kernel/linux/linux-renesas/0005-sched-fair-Avoid-pulling-tasks-from-non-overloaded-h.patch
parent109dea1d5c5a38807b098b588584636ae636a302 (diff)
This layer provides Energy Aware Scheduling (EAS) patcheseel_5.1.0eel_5.0.3eel_5.0.2eel/5.1.0eel/5.0.3eel/5.0.25.1.05.0.35.0.2eel
For the moment only for Renesas R-Car Gen3 SoC's. Can be expanded for other SoC's by setting the machine feature biglittle and provide the relevant EAS patches. Bug-AGL: SPEC-813 Change-Id: I2b5e69c515c33e57be19b30466fe208d7b8ac1a5 Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
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.patch81
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
+