The scheduler is currently unaware of frequency changes and the current compute capacity offered by the cpus. This patch is not the solution. It is a hack to give us something to experiment with for now.
A proper solution could be based on the frequency invariant load tracking proposed in the past: https://lkml.org/lkml/2013/4/16/289 The best way to get current compute capacity is likely to be architecture specific. A potential solution is therefore to let the architecture implement get_curr_capacity() instead. This patch should _not_ be considered safe. Signed-off-by: Morten Rasmussen <[email protected]> --- drivers/cpufreq/cpufreq.c | 2 ++ include/linux/sched.h | 2 ++ kernel/sched/fair.c | 11 +++++++++++ kernel/sched/sched.h | 2 ++ 4 files changed, 17 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index abda660..a2b788d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -28,6 +28,7 @@ #include <linux/slab.h> #include <linux/suspend.h> #include <linux/tick.h> +#include <linux/sched.h> #include <trace/events/power.h> /** @@ -315,6 +316,7 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, pr_debug("FREQ: %lu - CPU: %lu\n", (unsigned long)freqs->new, (unsigned long)freqs->cpu); trace_cpu_frequency(freqs->new, freqs->cpu); + set_curr_capacity(freqs->cpu, (freqs->new*1024)/policy->max); srcu_notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_POSTCHANGE, freqs); if (likely(policy) && likely(policy->cpu == freqs->cpu)) diff --git a/include/linux/sched.h b/include/linux/sched.h index e5d8d57..faebd87 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -3025,4 +3025,6 @@ static inline unsigned long rlimit_max(unsigned int limit) return task_rlimit_max(current, limit); } +void set_curr_capacity(int cpu, long capacity); + #endif diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 37e9ea1..9720f04 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7564,9 +7564,20 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) atomic64_set(&cfs_rq->decay_counter, 1); atomic_long_set(&cfs_rq->removed_load, 0); atomic_long_set(&cfs_rq->uw_removed_load, 0); + atomic_long_set(&cfs_rq->curr_capacity, 1024); #endif } +void set_curr_capacity(int cpu, long capacity) +{ + atomic_long_set(&cpu_rq(cpu)->cfs.curr_capacity, capacity); +} + +static inline unsigned long get_curr_capacity(int cpu) +{ + return atomic_long_read(&cpu_rq(cpu)->cfs.curr_capacity); +} + #ifdef CONFIG_FAIR_GROUP_SCHED static void task_move_group_fair(struct task_struct *p, int on_rq) { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 455d152..a6d5239 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -342,6 +342,8 @@ struct cfs_rq { u64 last_decay; atomic_long_t removed_load, uw_removed_load; + atomic_long_t curr_capacity; + #ifdef CONFIG_FAIR_GROUP_SCHED /* Required to track per-cpu representation of a task_group */ u32 tg_runnable_contrib; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
