From ccb2fe209dac9ff67f6351e783e610073afaaeaf Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 28 Jun 2006 13:49:52 -0700 Subject: [PATCH] [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 +++++++++-------------------- include/asm-generic/cputime.h | 2 + 2 files changed, 42 insertions(+), 98 deletions(-) diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 693e540481..a2add11e56 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); diff --git a/include/asm-generic/cputime.h b/include/asm-generic/cputime.h index 6f178563e3..09204e40d6 100644 --- a/include/asm-generic/cputime.h +++ b/include/asm-generic/cputime.h @@ -24,7 +24,9 @@ typedef u64 cputime64_t; #define cputime64_zero (0ULL) #define cputime64_add(__a, __b) ((__a) + (__b)) +#define cputime64_sub(__a, __b) ((__a) - (__b)) #define cputime64_to_jiffies64(__ct) (__ct) +#define jiffies64_to_cputime64(__jif) (__jif) #define cputime_to_cputime64(__ct) ((u64) __ct) -- 2.39.5