From 2f8a835c705794f71726eb12c06fb0f24fe07ed3 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 28 Jun 2006 13:51:19 -0700 Subject: [PATCH] [CPUFREQ] Make ondemand sampling per CPU and remove the mutex usage in sampling path. Make ondemand sampling per CPU and remove the mutex usage in sampling path. Signed-off-by: Alexey Starikovskiy Signed-off-by: Venkatesh Pallipadi Signed-off-by: Dave Jones --- drivers/cpufreq/cpufreq_ondemand.c | 72 +++++++++++++----------------- 1 file changed, 32 insertions(+), 40 deletions(-) diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index a2add11e56f1..18b016ea5f48 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -64,6 +64,7 @@ struct cpu_dbs_info_s { cputime64_t prev_cpu_idle; cputime64_t prev_cpu_wall; struct cpufreq_policy *cur_policy; + struct work_struct work; unsigned int enable; }; static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); @@ -81,7 +82,7 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */ static DEFINE_MUTEX (dbs_mutex); static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); -static struct workqueue_struct *dbs_workq; +static struct workqueue_struct *kondemand_wq; struct dbs_tuners { unsigned int sampling_rate; @@ -233,17 +234,15 @@ static struct attribute_group dbs_attr_group = { /************************** sysfs end ************************/ -static void dbs_check_cpu(int cpu) +static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) { unsigned int idle_ticks, total_ticks; unsigned int load; - struct cpu_dbs_info_s *this_dbs_info; cputime64_t cur_jiffies; struct cpufreq_policy *policy; unsigned int j; - this_dbs_info = &per_cpu(cpu_dbs_info, cpu); if (!this_dbs_info->enable) return; @@ -314,35 +313,29 @@ static void dbs_check_cpu(int cpu) static void do_dbs_timer(void *data) { - int i; - lock_cpu_hotplug(); - mutex_lock(&dbs_mutex); - for_each_online_cpu(i) - dbs_check_cpu(i); - queue_delayed_work(dbs_workq, &dbs_work, - usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); - mutex_unlock(&dbs_mutex); - unlock_cpu_hotplug(); + unsigned int cpu = smp_processor_id(); + struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); + + dbs_check_cpu(dbs_info); + queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, + usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); } -static inline void dbs_timer_init(void) +static inline void dbs_timer_init(unsigned int cpu) { - INIT_WORK(&dbs_work, do_dbs_timer, NULL); - if (!dbs_workq) - dbs_workq = create_singlethread_workqueue("ondemand"); - if (!dbs_workq) { - printk(KERN_ERR "ondemand: Cannot initialize kernel thread\n"); - return; - } - queue_delayed_work(dbs_workq, &dbs_work, - usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); + struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); + + INIT_WORK(&dbs_info->work, do_dbs_timer, 0); + queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, + usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); return; } -static inline void dbs_timer_exit(void) +static inline void dbs_timer_exit(unsigned int cpu) { - if (dbs_workq) - cancel_rearming_delayed_workqueue(dbs_workq, &dbs_work); + struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); + + cancel_rearming_delayed_workqueue(kondemand_wq, &dbs_info->work); } static int cpufreq_governor_dbs(struct cpufreq_policy *policy, @@ -370,6 +363,16 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, break; mutex_lock(&dbs_mutex); + dbs_enable++; + if (dbs_enable == 1) { + kondemand_wq = create_workqueue("kondemand"); + if (!kondemand_wq) { + printk(KERN_ERR "Creation of kondemand failed\n"); + dbs_enable--; + mutex_unlock(&dbs_mutex); + return -ENOSPC; + } + } for_each_cpu_mask(j, policy->cpus) { struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(cpu_dbs_info, j); @@ -380,7 +383,6 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, } this_dbs_info->enable = 1; sysfs_create_group(&policy->kobj, &dbs_attr_group); - dbs_enable++; /* * Start the timerschedule work, when this governor * is used for first time @@ -399,23 +401,20 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, def_sampling_rate = MIN_STAT_SAMPLING_RATE; dbs_tuners_ins.sampling_rate = def_sampling_rate; - dbs_timer_init(); } + dbs_timer_init(policy->cpu); mutex_unlock(&dbs_mutex); break; case CPUFREQ_GOV_STOP: mutex_lock(&dbs_mutex); + dbs_timer_exit(policy->cpu); this_dbs_info->enable = 0; sysfs_remove_group(&policy->kobj, &dbs_attr_group); dbs_enable--; - /* - * Stop the timerschedule work, when this governor - * is used for first time - */ if (dbs_enable == 0) - dbs_timer_exit(); + destroy_workqueue(kondemand_wq); mutex_unlock(&dbs_mutex); @@ -452,13 +451,6 @@ static int __init cpufreq_gov_dbs_init(void) static void __exit cpufreq_gov_dbs_exit(void) { - /* Make sure that the scheduled work is indeed not running. - Assumes the timer has been cancelled first. */ - if (dbs_workq) { - flush_workqueue(dbs_workq); - destroy_workqueue(dbs_workq); - } - cpufreq_unregister_governor(&cpufreq_gov_dbs); } -- 2.39.2