From ccb2fe209dac9ff67f6351e783e610073afaaeaf Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 28 Jun 2006 13:49:52 -0700 Subject: [CPUFREQ] Remove slowdown from ondemand sampling path. Remove slowdown from ondemand sampling path. This reduces the code path length in dbs_check_cpu() by half. slowdown was not used by ondemand by default. If there are any user level tools that were using this tunable, they may report error now. Signed-off-by: Alexey Starikovskiy Signed-off-by: Venkatesh Pallipadi Signed-off-by: Dave Jones --- drivers/cpufreq/cpufreq_ondemand.c | 138 +++++++++++-------------------------- 1 file changed, 40 insertions(+), 98 deletions(-) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 693e540481b4..a2add11e56f1 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -56,16 +56,14 @@ static unsigned int def_sampling_rate; #define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) #define MAX_SAMPLING_RATE (500 * def_sampling_rate) #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) -#define DEF_SAMPLING_DOWN_FACTOR (1) -#define MAX_SAMPLING_DOWN_FACTOR (10) #define TRANSITION_LATENCY_LIMIT (10 * 1000) static void do_dbs_timer(void *data); struct cpu_dbs_info_s { + cputime64_t prev_cpu_idle; + cputime64_t prev_cpu_wall; struct cpufreq_policy *cur_policy; - unsigned int prev_cpu_idle_up; - unsigned int prev_cpu_idle_down; unsigned int enable; }; static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); @@ -87,24 +85,26 @@ static struct workqueue_struct *dbs_workq; struct dbs_tuners { unsigned int sampling_rate; - unsigned int sampling_down_factor; unsigned int up_threshold; unsigned int ignore_nice; }; static struct dbs_tuners dbs_tuners_ins = { .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, - .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, .ignore_nice = 0, }; -static inline unsigned int get_cpu_idle_time(unsigned int cpu) +static inline cputime64_t get_cpu_idle_time(unsigned int cpu) { - return kstat_cpu(cpu).cpustat.idle + - kstat_cpu(cpu).cpustat.iowait + - ( dbs_tuners_ins.ignore_nice ? - kstat_cpu(cpu).cpustat.nice : - 0); + cputime64_t retval; + + retval = cputime64_add(kstat_cpu(cpu).cpustat.idle, + kstat_cpu(cpu).cpustat.iowait); + + if (dbs_tuners_ins.ignore_nice) + retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice); + + return retval; } /************************** sysfs interface ************************/ @@ -133,29 +133,9 @@ static ssize_t show_##file_name \ return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ } show_one(sampling_rate, sampling_rate); -show_one(sampling_down_factor, sampling_down_factor); show_one(up_threshold, up_threshold); show_one(ignore_nice_load, ignore_nice); -static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, - const char *buf, size_t count) -{ - unsigned int input; - int ret; - ret = sscanf (buf, "%u", &input); - if (ret != 1 ) - return -EINVAL; - - if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) - return -EINVAL; - - mutex_lock(&dbs_mutex); - dbs_tuners_ins.sampling_down_factor = input; - mutex_unlock(&dbs_mutex); - - return count; -} - static ssize_t store_sampling_rate(struct cpufreq_policy *unused, const char *buf, size_t count) { @@ -217,12 +197,12 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, } dbs_tuners_ins.ignore_nice = input; - /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ + /* we need to re-evaluate prev_cpu_idle */ for_each_online_cpu(j) { - struct cpu_dbs_info_s *j_dbs_info; - j_dbs_info = &per_cpu(cpu_dbs_info, j); - j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); - j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; + struct cpu_dbs_info_s *dbs_info; + dbs_info = &per_cpu(cpu_dbs_info, j); + dbs_info->prev_cpu_idle = get_cpu_idle_time(j); + dbs_info->prev_cpu_wall = get_jiffies_64(); } mutex_unlock(&dbs_mutex); @@ -234,7 +214,6 @@ static struct freq_attr _name = \ __ATTR(_name, 0644, show_##_name, store_##_name) define_one_rw(sampling_rate); -define_one_rw(sampling_down_factor); define_one_rw(up_threshold); define_one_rw(ignore_nice_load); @@ -242,7 +221,6 @@ static struct attribute * dbs_attributes[] = { &sampling_rate_max.attr, &sampling_rate_min.attr, &sampling_rate.attr, - &sampling_down_factor.attr, &up_threshold.attr, &ignore_nice_load.attr, NULL @@ -257,11 +235,10 @@ static struct attribute_group dbs_attr_group = { static void dbs_check_cpu(int cpu) { - unsigned int idle_ticks, up_idle_ticks, total_ticks; - unsigned int freq_next; - unsigned int freq_down_sampling_rate; - static int down_skip[NR_CPUS]; + 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; @@ -271,10 +248,14 @@ static void dbs_check_cpu(int cpu) return; policy = this_dbs_info->cur_policy; + cur_jiffies = jiffies64_to_cputime64(get_jiffies_64()); + total_ticks = (unsigned int) cputime64_sub(cur_jiffies, + this_dbs_info->prev_cpu_wall); + this_dbs_info->prev_cpu_wall = cur_jiffies; /* * Every sampling_rate, we check, if current idle time is less * than 20% (default), then we try to increase frequency - * Every sampling_rate*sampling_down_factor, we look for a the lowest + * Every sampling_rate, we look for a the lowest * frequency which can sustain the load while keeping idle time over * 30%. If such a frequency exist, we try to decrease to this frequency. * @@ -283,36 +264,26 @@ static void dbs_check_cpu(int cpu) * 5% (default) of current frequency */ - /* Check for frequency increase */ + /* Get Idle Time */ idle_ticks = UINT_MAX; for_each_cpu_mask(j, policy->cpus) { - unsigned int tmp_idle_ticks, total_idle_ticks; + cputime64_t total_idle_ticks; + unsigned int tmp_idle_ticks; struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(cpu_dbs_info, j); total_idle_ticks = get_cpu_idle_time(j); - tmp_idle_ticks = total_idle_ticks - - j_dbs_info->prev_cpu_idle_up; - j_dbs_info->prev_cpu_idle_up = total_idle_ticks; + tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks, + j_dbs_info->prev_cpu_idle); + j_dbs_info->prev_cpu_idle = total_idle_ticks; if (tmp_idle_ticks < idle_ticks) idle_ticks = tmp_idle_ticks; } + load = (100 * (total_ticks - idle_ticks)) / total_ticks; - /* Scale idle ticks by 100 and compare with up and down ticks */ - idle_ticks *= 100; - up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * - usecs_to_jiffies(dbs_tuners_ins.sampling_rate); - - if (idle_ticks < up_idle_ticks) { - down_skip[cpu] = 0; - for_each_cpu_mask(j, policy->cpus) { - struct cpu_dbs_info_s *j_dbs_info; - - j_dbs_info = &per_cpu(cpu_dbs_info, j); - j_dbs_info->prev_cpu_idle_down = - j_dbs_info->prev_cpu_idle_up; - } + /* Check for frequency increase */ + if (load > dbs_tuners_ins.up_threshold) { /* if we are already at full speed then break out early */ if (policy->cur == policy->max) return; @@ -323,50 +294,22 @@ static void dbs_check_cpu(int cpu) } /* Check for frequency decrease */ - down_skip[cpu]++; - if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) - return; - - idle_ticks = UINT_MAX; - for_each_cpu_mask(j, policy->cpus) { - unsigned int tmp_idle_ticks, total_idle_ticks; - struct cpu_dbs_info_s *j_dbs_info; - - j_dbs_info = &per_cpu(cpu_dbs_info, j); - /* Check for frequency decrease */ - total_idle_ticks = j_dbs_info->prev_cpu_idle_up; - tmp_idle_ticks = total_idle_ticks - - j_dbs_info->prev_cpu_idle_down; - j_dbs_info->prev_cpu_idle_down = total_idle_ticks; - - if (tmp_idle_ticks < idle_ticks) - idle_ticks = tmp_idle_ticks; - } - - down_skip[cpu] = 0; /* if we cannot reduce the frequency anymore, break out early */ if (policy->cur == policy->min) return; - /* Compute how many ticks there are between two measurements */ - freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * - dbs_tuners_ins.sampling_down_factor; - total_ticks = usecs_to_jiffies(freq_down_sampling_rate); - /* * The optimal frequency is the frequency that is the lowest that * can support the current CPU usage without triggering the up * policy. To be safe, we focus 10 points under the threshold. */ - freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks; - freq_next = (freq_next * policy->cur) / + if (load < (dbs_tuners_ins.up_threshold - 10)) { + unsigned int freq_next; + freq_next = (policy->cur * load) / (dbs_tuners_ins.up_threshold - 10); - if (freq_next < policy->min) - freq_next = policy->min; - - if (freq_next <= ((policy->cur * 95) / 100)) __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); + } } static void do_dbs_timer(void *data) @@ -432,9 +375,8 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, j_dbs_info = &per_cpu(cpu_dbs_info, j); j_dbs_info->cur_policy = policy; - j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); - j_dbs_info->prev_cpu_idle_down - = j_dbs_info->prev_cpu_idle_up; + j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j); + j_dbs_info->prev_cpu_wall = get_jiffies_64(); } this_dbs_info->enable = 1; sysfs_create_group(&policy->kobj, &dbs_attr_group); -- cgit v1.2.1 From 2f8a835c705794f71726eb12c06fb0f24fe07ed3 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 28 Jun 2006 13:51:19 -0700 Subject: [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(-) (limited to 'drivers/cpufreq') 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); } -- cgit v1.2.1 From ffac80e925e54d84f6ea580231aa46d0ef051756 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 28 Jun 2006 13:52:18 -0700 Subject: [CPUFREQ] Misc cleanups in ondemand. Misc cleanups in ondemand. Should have zero functional impact. Also adding Alexey as author. Signed-off-by: Alexey Starikovskiy Signed-off-by: Venkatesh Pallipadi Signed-off-by: Dave Jones --- drivers/cpufreq/cpufreq_ondemand.c | 50 +++++++++++++++----------------------- 1 file changed, 19 insertions(+), 31 deletions(-) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 18b016ea5f48..87299924e735 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -12,22 +12,11 @@ #include #include -#include #include -#include -#include #include -#include -#include -#include -#include #include -#include -#include -#include #include #include -#include #include /* @@ -79,8 +68,7 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */ * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock * is recursive for the same process. -Venki */ -static DEFINE_MUTEX (dbs_mutex); -static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); +static DEFINE_MUTEX(dbs_mutex); static struct workqueue_struct *kondemand_wq; @@ -142,7 +130,7 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused, { unsigned int input; int ret; - ret = sscanf (buf, "%u", &input); + ret = sscanf(buf, "%u", &input); mutex_lock(&dbs_mutex); if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { @@ -161,7 +149,7 @@ static ssize_t store_up_threshold(struct cpufreq_policy *unused, { unsigned int input; int ret; - ret = sscanf (buf, "%u", &input); + ret = sscanf(buf, "%u", &input); mutex_lock(&dbs_mutex); if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || @@ -184,7 +172,7 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, unsigned int j; - ret = sscanf (buf, "%u", &input); + ret = sscanf(buf, "%u", &input); if ( ret != 1 ) return -EINVAL; @@ -349,8 +337,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, switch (event) { case CPUFREQ_GOV_START: - if ((!cpu_online(cpu)) || - (!policy->cur)) + if ((!cpu_online(cpu)) || (!policy->cur)) return -EINVAL; if (policy->cpuinfo.transition_latency > @@ -424,13 +411,13 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, lock_cpu_hotplug(); mutex_lock(&dbs_mutex); if (policy->max < this_dbs_info->cur_policy->cur) - __cpufreq_driver_target( - this_dbs_info->cur_policy, - policy->max, CPUFREQ_RELATION_H); + __cpufreq_driver_target(this_dbs_info->cur_policy, + policy->max, + CPUFREQ_RELATION_H); else if (policy->min > this_dbs_info->cur_policy->cur) - __cpufreq_driver_target( - this_dbs_info->cur_policy, - policy->min, CPUFREQ_RELATION_L); + __cpufreq_driver_target(this_dbs_info->cur_policy, + policy->min, + CPUFREQ_RELATION_L); mutex_unlock(&dbs_mutex); unlock_cpu_hotplug(); break; @@ -439,9 +426,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, } static struct cpufreq_governor cpufreq_gov_dbs = { - .name = "ondemand", - .governor = cpufreq_governor_dbs, - .owner = THIS_MODULE, + .name = "ondemand", + .governor = cpufreq_governor_dbs, + .owner = THIS_MODULE, }; static int __init cpufreq_gov_dbs_init(void) @@ -455,10 +442,11 @@ static void __exit cpufreq_gov_dbs_exit(void) } -MODULE_AUTHOR ("Venkatesh Pallipadi "); -MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for " - "Low Latency Frequency Transition capable processors"); -MODULE_LICENSE ("GPL"); +MODULE_AUTHOR("Venkatesh Pallipadi "); +MODULE_AUTHOR("Alexey Starikovskiy "); +MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " + "Low Latency Frequency Transition capable processors"); +MODULE_LICENSE("GPL"); module_init(cpufreq_gov_dbs_init); module_exit(cpufreq_gov_dbs_exit); -- cgit v1.2.1