From 40c3aaa56a68455a1c8eccff1bb23d853d8e239c Mon Sep 17 00:00:00 2001 From: Joonwoo Park Date: Tue, 20 Dec 2016 15:23:53 -0800 Subject: cpufreq: sched: update capacity request upon tick always At present, sched_freq_tick() skips updating of capacity update when current frequency is fmax. This can cause incorrect frequency drop when a CPU bound task goes into sleep for example : 1) A task (A) enqueues onto CPU 0 and executes for long time. 2) A new task (B) which has low task demand enqueues onto CPU 1 and executes long so becomes a CPU bound task. 3) Both CPU 0 and 1 gets scheduler tick but skip sched_freq_tick() since current frequency is fmax. 4) Task (A) sleeps and lower the CPU 0's capacity request. 5) Because task (B) voted CPU capacity at step 2 with low demand and skipped to request afterwards, cluster frequency for both CPU 0 and 1 drops to match capacity voted by CPU 1 at step 2 even though task (B) on CPU 1 requires max capacity. Fix such incorrectness by not skipping CPU capacity voting at tick path. Change-Id: Ieb46af1ac96ffce7a5532c58c7f07bf1ada06b86 Signed-off-by: Joonwoo Park Signed-off-by: Vikram Mulukutla --- kernel/sched/core.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fec7b2c4f9fd..f747e373ed6f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3025,16 +3025,9 @@ static void sched_freq_tick_walt(int cpu) static void sched_freq_tick(int cpu) { - unsigned long capacity_orig, capacity_curr; - if (!sched_freq()) return; - capacity_orig = capacity_orig_of(cpu); - capacity_curr = capacity_curr_of(cpu); - if (capacity_curr == capacity_orig) - return; - _sched_freq_tick(cpu); } #else -- cgit v1.2.3