diff options
| -rw-r--r-- | Documentation/scheduler/sched-hmp.txt | 4 | ||||
| -rw-r--r-- | kernel/sched/core.c | 6 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 42 | ||||
| -rw-r--r-- | kernel/sysctl.c | 2 |
4 files changed, 40 insertions, 14 deletions
diff --git a/Documentation/scheduler/sched-hmp.txt b/Documentation/scheduler/sched-hmp.txt index aeecb0c15657..54add3c4b94f 100644 --- a/Documentation/scheduler/sched-hmp.txt +++ b/Documentation/scheduler/sched-hmp.txt @@ -1254,7 +1254,7 @@ idle CPUs which are not completely idle, increasing task packing behavior. Appears at: /proc/sys/kernel/sched_min_runtime -Default value: 200000000 (200ms) +Default value: 0 (0 ms) This tunable helps avouid frequent migration of task on account of energy-awareness. During scheduler tick, a check is made (in migration_needed()) @@ -1267,6 +1267,8 @@ is used in migration_needed() to avoid "frequent" migrations. Once a task has been associated with a cpu (in either running or runnable state) for more than 'sched_min_vruntime' ns, it is considered eligible for migration in tick path on account of energy awareness reasons. +The same logic also applies to the load balancer path to avoid frequent +migrations due to energy awareness. ========================= 8. HMP SCHEDULER TRACE POINTS diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f3d385c2dac6..290b8df6f6e0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2846,7 +2846,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) trace_sched_migrate_task(p, new_cpu, pct_task_load(p)); - note_run_start(p, -1); + note_run_start(p, sched_clock()); if (task_cpu(p) != new_cpu) { if (p->sched_class->migrate_task_rq) @@ -3584,6 +3584,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) if (src_cpu != cpu) { wake_flags |= WF_MIGRATED; set_task_cpu(p, cpu); + } else { + note_run_start(p, wallclock); } #endif /* CONFIG_SMP */ @@ -4786,7 +4788,6 @@ static void __sched notrace __schedule(bool preempt) prev->state = TASK_RUNNING; } else { deactivate_task(rq, prev, DEQUEUE_SLEEP); - note_run_start(prev, -1); prev->on_rq = 0; /* @@ -4815,7 +4816,6 @@ static void __sched notrace __schedule(bool preempt) clear_tsk_need_resched(prev); clear_preempt_need_resched(); rq->clock_skip_update = 0; - note_run_start(next, wallclock); BUG_ON(task_cpu(next) != cpu_of(rq)); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f0d34f818428..910e50456c60 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2543,7 +2543,12 @@ unsigned int __read_mostly sched_init_task_load_pelt; unsigned int __read_mostly sched_init_task_load_windows; unsigned int __read_mostly sysctl_sched_init_task_load_pct = 15; -unsigned int __read_mostly sysctl_sched_min_runtime = 200000000; /* 200 ms */ +/* + * Keep these two below in sync. One is in unit of ns and the + * other in unit of us. + */ +unsigned int __read_mostly sysctl_sched_min_runtime = 0; /* 0 ms */ +u64 __read_mostly sched_min_runtime = 0; /* 0 ms */ static inline unsigned int task_load(struct task_struct *p) { @@ -3511,6 +3516,10 @@ int sched_hmp_proc_update_handler(struct ctl_table *table, int write, if (ret || !write || !sched_enable_hmp) return ret; + if (data == &sysctl_sched_min_runtime) { + sched_min_runtime = ((u64) sysctl_sched_min_runtime) * 1000; + return 0; + } if ((sysctl_sched_downmigrate_pct > sysctl_sched_upmigrate_pct) || *data > 100) { *data = old_val; @@ -3610,10 +3619,6 @@ static int lower_power_cpu_available(struct task_struct *p, int cpu) int i; int lowest_power_cpu = task_cpu(p); int lowest_power = power_cost(p, task_cpu(p)); - u64 delta = sched_clock() - p->run_start; - - if (delta < sysctl_sched_min_runtime) - return 0; /* Is a lower-powered idle CPU available which will fit this task? */ for_each_cpu_and(i, tsk_cpus_allowed(p), cpu_online_mask) { @@ -3630,6 +3635,7 @@ static int lower_power_cpu_available(struct task_struct *p, int cpu) } static inline int is_cpu_throttling_imminent(int cpu); +static inline int is_task_migration_throttled(struct task_struct *p); /* * Check if a task is on the "wrong" cpu (i.e its current cpu is not the ideal @@ -3663,6 +3669,7 @@ static inline int migration_needed(struct rq *rq, struct task_struct *p) return MOVE_TO_BIG_CPU; if (sched_enable_power_aware && + !is_task_migration_throttled(p) && is_cpu_throttling_imminent(cpu_of(rq)) && lower_power_cpu_available(p, cpu_of(rq))) return MOVE_TO_POWER_EFFICIENT_CPU; @@ -3737,6 +3744,13 @@ static inline int is_cpu_throttling_imminent(int cpu) return throttling; } +static inline int is_task_migration_throttled(struct task_struct *p) +{ + u64 delta = sched_clock() - p->run_start; + + return delta < sched_min_runtime; +} + unsigned int cpu_temp(int cpu) { struct cpu_pwr_stats *per_cpu_info = get_cpu_pwr_stats(); @@ -3808,6 +3822,11 @@ static inline int is_cpu_throttling_imminent(int cpu) return 0; } +static inline int is_task_migration_throttled(struct task_struct *p) +{ + return 0; +} + unsigned int cpu_temp(int cpu) { return 0; @@ -7768,6 +7787,8 @@ static inline enum group_type group_classify(struct sched_group *group, struct sg_lb_stats *sgs, struct lb_env *env) { + int cpu; + if (sgs->group_no_capacity) { env->flags &= ~LBF_PWR_ACTIVE_BALANCE; return group_overloaded; @@ -7780,13 +7801,16 @@ group_type group_classify(struct sched_group *group, /* Mark a less power-efficient CPU as busy only if we haven't - * seen a busy group yet. We want to prioritize spreading - * work over power optimization. */ + * seen a busy group yet and we are close to throttling. We want to + * prioritize spreading work over power optimization. + */ + cpu = cpumask_first(sched_group_cpus(group)); if ((capacity(env->dst_rq) == group_rq_capacity(group)) && sgs->sum_nr_running && (env->idle != CPU_NOT_IDLE) && power_cost_at_freq(env->dst_cpu, 0) < - power_cost_at_freq(cpumask_first(sched_group_cpus(group)), 0) && - is_cpu_throttling_imminent(cpumask_first(sched_group_cpus(group)))) { + power_cost_at_freq(cpu, 0) && + !is_task_migration_throttled(cpu_rq(cpu)->curr) && + is_cpu_throttling_imminent(cpu)) { env->flags |= LBF_PWR_ACTIVE_BALANCE; return group_ea; } diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 9c2719cc9cc9..5e171b035482 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -377,7 +377,7 @@ static struct ctl_table kern_table[] = { .data = &sysctl_sched_min_runtime, .maxlen = sizeof(unsigned int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = sched_hmp_proc_update_handler, }, { .procname = "sched_spill_load", |