From bfa1dd2bfda910b60e425974fd5dc94a6bdaccc4 Mon Sep 17 00:00:00 2001 From: Srinath Sridharan Date: Fri, 29 Jul 2016 17:50:11 +0100 Subject: [PATCH] sched/fair: Favor higher cpus only for boosted tasks This CL separates the notion of boost and prefer_idle schedtune attributes in cpu selection. Today only top-app tasks are boosted. The CPU selection is slightly tweaked such that higher order cpus are preferred only for boosted tasks (top-app) and the rest would be skewed towards lower order cpus. This avoids starvation issues for fg tasks when interacting with high priority top-app tasks (a problem often seen in the case of system_server). bug: 30245369 bug: 30292998 Change-Id: I0377e00893b9f6586eec55632a265518fd2fa8a1 Conflicts: kernel/sched/fair.c --- kernel/sched/fair.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 88eae79d1a3c..e7f9afe29c61 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5612,7 +5612,7 @@ done: return target; } -static inline int find_best_target(struct task_struct *p, bool prefer_idle) +static inline int find_best_target(struct task_struct *p, bool boosted, bool prefer_idle) { int iter_cpu; int target_cpu = -1; @@ -5630,9 +5630,9 @@ static inline int find_best_target(struct task_struct *p, bool prefer_idle) int idle_idx; /* - * favor higher cpus for tasks that prefer idle cores + * Iterate from higher cpus for boosted tasks. */ - int i = prefer_idle ? NR_CPUS-iter_cpu-1 : iter_cpu; + int i = boosted ? NR_CPUS-iter_cpu-1 : iter_cpu; if (!cpu_online(i) || !cpumask_test_cpu(i, tsk_cpus_allowed(p))) continue; @@ -5802,7 +5802,7 @@ static int energy_aware_wake_cpu(struct task_struct *p, int target, int sync) bool boosted = 0; bool prefer_idle = 0; #endif - int tmp_target = find_best_target(p, boosted || prefer_idle); + int tmp_target = find_best_target(p, boosted, prefer_idle); if (tmp_target >= 0) { target_cpu = tmp_target; if ((boosted || prefer_idle) && idle_cpu(target_cpu)) -- 2.34.1