681 строка
18 KiB
C
681 строка
18 KiB
C
/*
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* drivers/cpufreq/cpufreq_conservative.c
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*
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* Copyright (C) 2001 Russell King
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* (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
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* Jun Nakajima <jun.nakajima@intel.com>
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* (C) 2009 Alexander Clouter <alex@digriz.org.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/cpufreq.h>
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#include <linux/cpu.h>
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#include <linux/jiffies.h>
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#include <linux/kernel_stat.h>
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#include <linux/mutex.h>
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#include <linux/hrtimer.h>
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#include <linux/tick.h>
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#include <linux/ktime.h>
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#include <linux/sched.h>
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/*
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* dbs is used in this file as a shortform for demandbased switching
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* It helps to keep variable names smaller, simpler
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*/
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#define DEF_FREQUENCY_UP_THRESHOLD (80)
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#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
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/*
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* The polling frequency of this governor depends on the capability of
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* the processor. Default polling frequency is 1000 times the transition
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* latency of the processor. The governor will work on any processor with
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* transition latency <= 10mS, using appropriate sampling
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* rate.
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* For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
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* this governor will not work.
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* All times here are in uS.
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*/
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#define MIN_SAMPLING_RATE_RATIO (2)
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static unsigned int min_sampling_rate;
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#define LATENCY_MULTIPLIER (1000)
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#define MIN_LATENCY_MULTIPLIER (100)
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#define DEF_SAMPLING_DOWN_FACTOR (1)
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#define MAX_SAMPLING_DOWN_FACTOR (10)
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#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
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static void do_dbs_timer(struct work_struct *work);
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struct cpu_dbs_info_s {
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cputime64_t prev_cpu_idle;
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cputime64_t prev_cpu_wall;
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cputime64_t prev_cpu_nice;
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struct cpufreq_policy *cur_policy;
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struct delayed_work work;
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unsigned int down_skip;
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unsigned int requested_freq;
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int cpu;
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unsigned int enable:1;
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};
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static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
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static unsigned int dbs_enable; /* number of CPUs using this policy */
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/*
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* DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
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* lock and dbs_mutex. cpu_hotplug lock should always be held before
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* dbs_mutex. If any function that can potentially take cpu_hotplug lock
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* (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
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* cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
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* is recursive for the same process. -Venki
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* DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, because it
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* would deadlock with cancel_delayed_work_sync(), which is needed for proper
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* raceless workqueue teardown.
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*/
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static DEFINE_MUTEX(dbs_mutex);
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static struct workqueue_struct *kconservative_wq;
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static struct dbs_tuners {
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unsigned int sampling_rate;
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unsigned int sampling_down_factor;
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unsigned int up_threshold;
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unsigned int down_threshold;
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unsigned int ignore_nice;
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unsigned int freq_step;
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} dbs_tuners_ins = {
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.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
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.down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
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.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
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.ignore_nice = 0,
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.freq_step = 5,
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};
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static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
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cputime64_t *wall)
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{
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cputime64_t idle_time;
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cputime64_t cur_wall_time;
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cputime64_t busy_time;
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cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
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busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
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kstat_cpu(cpu).cpustat.system);
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busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);
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busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);
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busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);
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busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);
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idle_time = cputime64_sub(cur_wall_time, busy_time);
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if (wall)
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*wall = cur_wall_time;
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return idle_time;
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}
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static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
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{
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u64 idle_time = get_cpu_idle_time_us(cpu, wall);
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if (idle_time == -1ULL)
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return get_cpu_idle_time_jiffy(cpu, wall);
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return idle_time;
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}
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/* keep track of frequency transitions */
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static int
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dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
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void *data)
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{
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struct cpufreq_freqs *freq = data;
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struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info,
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freq->cpu);
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struct cpufreq_policy *policy;
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if (!this_dbs_info->enable)
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return 0;
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policy = this_dbs_info->cur_policy;
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/*
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* we only care if our internally tracked freq moves outside
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* the 'valid' ranges of freqency available to us otherwise
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* we do not change it
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*/
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if (this_dbs_info->requested_freq > policy->max
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|| this_dbs_info->requested_freq < policy->min)
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this_dbs_info->requested_freq = freq->new;
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return 0;
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}
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static struct notifier_block dbs_cpufreq_notifier_block = {
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.notifier_call = dbs_cpufreq_notifier
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};
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/************************** sysfs interface ************************/
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static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
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{
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printk_once(KERN_INFO "CPUFREQ: conservative sampling_rate_max "
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"sysfs file is deprecated - used by: %s\n", current->comm);
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return sprintf(buf, "%u\n", -1U);
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}
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static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
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{
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return sprintf(buf, "%u\n", min_sampling_rate);
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}
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#define define_one_ro(_name) \
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static struct freq_attr _name = \
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__ATTR(_name, 0444, show_##_name, NULL)
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define_one_ro(sampling_rate_max);
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define_one_ro(sampling_rate_min);
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/* cpufreq_conservative Governor Tunables */
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#define show_one(file_name, object) \
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static ssize_t show_##file_name \
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(struct cpufreq_policy *unused, char *buf) \
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{ \
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return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
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}
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show_one(sampling_rate, sampling_rate);
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show_one(sampling_down_factor, sampling_down_factor);
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show_one(up_threshold, up_threshold);
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show_one(down_threshold, down_threshold);
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show_one(ignore_nice_load, ignore_nice);
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show_one(freq_step, freq_step);
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static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
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const char *buf, size_t count)
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{
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unsigned int input;
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int ret;
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ret = sscanf(buf, "%u", &input);
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if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
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return -EINVAL;
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mutex_lock(&dbs_mutex);
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dbs_tuners_ins.sampling_down_factor = input;
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mutex_unlock(&dbs_mutex);
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return count;
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}
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static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
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const char *buf, size_t count)
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{
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unsigned int input;
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int ret;
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ret = sscanf(buf, "%u", &input);
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if (ret != 1)
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return -EINVAL;
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mutex_lock(&dbs_mutex);
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dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
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mutex_unlock(&dbs_mutex);
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return count;
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}
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static ssize_t store_up_threshold(struct cpufreq_policy *unused,
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const char *buf, size_t count)
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{
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unsigned int input;
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int ret;
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ret = sscanf(buf, "%u", &input);
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mutex_lock(&dbs_mutex);
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if (ret != 1 || input > 100 ||
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input <= dbs_tuners_ins.down_threshold) {
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mutex_unlock(&dbs_mutex);
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return -EINVAL;
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}
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dbs_tuners_ins.up_threshold = input;
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mutex_unlock(&dbs_mutex);
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return count;
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}
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static ssize_t store_down_threshold(struct cpufreq_policy *unused,
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const char *buf, size_t count)
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{
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unsigned int input;
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int ret;
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ret = sscanf(buf, "%u", &input);
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mutex_lock(&dbs_mutex);
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/* cannot be lower than 11 otherwise freq will not fall */
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if (ret != 1 || input < 11 || input > 100 ||
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input >= dbs_tuners_ins.up_threshold) {
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mutex_unlock(&dbs_mutex);
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return -EINVAL;
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}
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dbs_tuners_ins.down_threshold = input;
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mutex_unlock(&dbs_mutex);
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return count;
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}
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static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
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const char *buf, size_t count)
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{
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unsigned int input;
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int ret;
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unsigned int j;
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ret = sscanf(buf, "%u", &input);
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if (ret != 1)
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return -EINVAL;
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if (input > 1)
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input = 1;
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mutex_lock(&dbs_mutex);
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if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
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mutex_unlock(&dbs_mutex);
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return count;
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}
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dbs_tuners_ins.ignore_nice = input;
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/* we need to re-evaluate prev_cpu_idle */
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for_each_online_cpu(j) {
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struct cpu_dbs_info_s *dbs_info;
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dbs_info = &per_cpu(cpu_dbs_info, j);
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dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
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&dbs_info->prev_cpu_wall);
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if (dbs_tuners_ins.ignore_nice)
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dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
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}
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mutex_unlock(&dbs_mutex);
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return count;
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}
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static ssize_t store_freq_step(struct cpufreq_policy *policy,
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const char *buf, size_t count)
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{
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unsigned int input;
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int ret;
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ret = sscanf(buf, "%u", &input);
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if (ret != 1)
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return -EINVAL;
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if (input > 100)
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input = 100;
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/* no need to test here if freq_step is zero as the user might actually
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* want this, they would be crazy though :) */
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mutex_lock(&dbs_mutex);
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dbs_tuners_ins.freq_step = input;
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mutex_unlock(&dbs_mutex);
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return count;
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}
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#define define_one_rw(_name) \
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static struct freq_attr _name = \
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__ATTR(_name, 0644, show_##_name, store_##_name)
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define_one_rw(sampling_rate);
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define_one_rw(sampling_down_factor);
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define_one_rw(up_threshold);
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define_one_rw(down_threshold);
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define_one_rw(ignore_nice_load);
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define_one_rw(freq_step);
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static struct attribute *dbs_attributes[] = {
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&sampling_rate_max.attr,
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&sampling_rate_min.attr,
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&sampling_rate.attr,
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&sampling_down_factor.attr,
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&up_threshold.attr,
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&down_threshold.attr,
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&ignore_nice_load.attr,
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&freq_step.attr,
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NULL
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};
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static struct attribute_group dbs_attr_group = {
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.attrs = dbs_attributes,
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.name = "conservative",
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};
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/************************** sysfs end ************************/
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static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
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{
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unsigned int load = 0;
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unsigned int freq_target;
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struct cpufreq_policy *policy;
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unsigned int j;
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policy = this_dbs_info->cur_policy;
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/*
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* Every sampling_rate, we check, if current idle time is less
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* than 20% (default), then we try to increase frequency
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* Every sampling_rate*sampling_down_factor, we check, if current
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* idle time is more than 80%, then we try to decrease frequency
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*
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* Any frequency increase takes it to the maximum frequency.
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* Frequency reduction happens at minimum steps of
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* 5% (default) of maximum frequency
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*/
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/* Get Absolute Load */
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for_each_cpu(j, policy->cpus) {
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struct cpu_dbs_info_s *j_dbs_info;
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cputime64_t cur_wall_time, cur_idle_time;
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unsigned int idle_time, wall_time;
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j_dbs_info = &per_cpu(cpu_dbs_info, j);
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cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
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wall_time = (unsigned int) cputime64_sub(cur_wall_time,
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j_dbs_info->prev_cpu_wall);
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j_dbs_info->prev_cpu_wall = cur_wall_time;
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idle_time = (unsigned int) cputime64_sub(cur_idle_time,
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j_dbs_info->prev_cpu_idle);
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j_dbs_info->prev_cpu_idle = cur_idle_time;
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if (dbs_tuners_ins.ignore_nice) {
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cputime64_t cur_nice;
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unsigned long cur_nice_jiffies;
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cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,
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j_dbs_info->prev_cpu_nice);
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/*
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* Assumption: nice time between sampling periods will
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* be less than 2^32 jiffies for 32 bit sys
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*/
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cur_nice_jiffies = (unsigned long)
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cputime64_to_jiffies64(cur_nice);
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j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
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idle_time += jiffies_to_usecs(cur_nice_jiffies);
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}
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if (unlikely(!wall_time || wall_time < idle_time))
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continue;
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load = 100 * (wall_time - idle_time) / wall_time;
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}
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/*
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* break out if we 'cannot' reduce the speed as the user might
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* want freq_step to be zero
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*/
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if (dbs_tuners_ins.freq_step == 0)
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return;
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/* Check for frequency increase */
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if (load > dbs_tuners_ins.up_threshold) {
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this_dbs_info->down_skip = 0;
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/* if we are already at full speed then break out early */
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if (this_dbs_info->requested_freq == policy->max)
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return;
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freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
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/* max freq cannot be less than 100. But who knows.... */
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if (unlikely(freq_target == 0))
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freq_target = 5;
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this_dbs_info->requested_freq += freq_target;
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if (this_dbs_info->requested_freq > policy->max)
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this_dbs_info->requested_freq = policy->max;
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__cpufreq_driver_target(policy, this_dbs_info->requested_freq,
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CPUFREQ_RELATION_H);
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return;
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}
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/*
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* The optimal frequency is the frequency that is the lowest that
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* can support the current CPU usage without triggering the up
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* policy. To be safe, we focus 10 points under the threshold.
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*/
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if (load < (dbs_tuners_ins.down_threshold - 10)) {
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freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
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this_dbs_info->requested_freq -= freq_target;
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if (this_dbs_info->requested_freq < policy->min)
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this_dbs_info->requested_freq = policy->min;
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/*
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* if we cannot reduce the frequency anymore, break out early
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*/
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if (policy->cur == policy->min)
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return;
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__cpufreq_driver_target(policy, this_dbs_info->requested_freq,
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CPUFREQ_RELATION_H);
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return;
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}
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}
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static void do_dbs_timer(struct work_struct *work)
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{
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struct cpu_dbs_info_s *dbs_info =
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container_of(work, struct cpu_dbs_info_s, work.work);
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unsigned int cpu = dbs_info->cpu;
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/* We want all CPUs to do sampling nearly on same jiffy */
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int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
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delay -= jiffies % delay;
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if (lock_policy_rwsem_write(cpu) < 0)
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return;
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if (!dbs_info->enable) {
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unlock_policy_rwsem_write(cpu);
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return;
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}
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dbs_check_cpu(dbs_info);
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queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);
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unlock_policy_rwsem_write(cpu);
|
|
}
|
|
|
|
static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
|
|
{
|
|
/* We want all CPUs to do sampling nearly on same jiffy */
|
|
int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
|
|
delay -= jiffies % delay;
|
|
|
|
dbs_info->enable = 1;
|
|
INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
|
|
queue_delayed_work_on(dbs_info->cpu, kconservative_wq, &dbs_info->work,
|
|
delay);
|
|
}
|
|
|
|
static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
|
|
{
|
|
dbs_info->enable = 0;
|
|
cancel_delayed_work_sync(&dbs_info->work);
|
|
}
|
|
|
|
static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
|
|
unsigned int event)
|
|
{
|
|
unsigned int cpu = policy->cpu;
|
|
struct cpu_dbs_info_s *this_dbs_info;
|
|
unsigned int j;
|
|
int rc;
|
|
|
|
this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
|
|
|
|
switch (event) {
|
|
case CPUFREQ_GOV_START:
|
|
if ((!cpu_online(cpu)) || (!policy->cur))
|
|
return -EINVAL;
|
|
|
|
if (this_dbs_info->enable) /* Already enabled */
|
|
break;
|
|
|
|
mutex_lock(&dbs_mutex);
|
|
|
|
rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
|
|
if (rc) {
|
|
mutex_unlock(&dbs_mutex);
|
|
return rc;
|
|
}
|
|
|
|
for_each_cpu(j, policy->cpus) {
|
|
struct cpu_dbs_info_s *j_dbs_info;
|
|
j_dbs_info = &per_cpu(cpu_dbs_info, j);
|
|
j_dbs_info->cur_policy = policy;
|
|
|
|
j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
|
|
&j_dbs_info->prev_cpu_wall);
|
|
if (dbs_tuners_ins.ignore_nice) {
|
|
j_dbs_info->prev_cpu_nice =
|
|
kstat_cpu(j).cpustat.nice;
|
|
}
|
|
}
|
|
this_dbs_info->down_skip = 0;
|
|
this_dbs_info->requested_freq = policy->cur;
|
|
|
|
dbs_enable++;
|
|
/*
|
|
* Start the timerschedule work, when this governor
|
|
* is used for first time
|
|
*/
|
|
if (dbs_enable == 1) {
|
|
unsigned int latency;
|
|
/* policy latency is in nS. Convert it to uS first */
|
|
latency = policy->cpuinfo.transition_latency / 1000;
|
|
if (latency == 0)
|
|
latency = 1;
|
|
|
|
/*
|
|
* conservative does not implement micro like ondemand
|
|
* governor, thus we are bound to jiffes/HZ
|
|
*/
|
|
min_sampling_rate =
|
|
MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10);
|
|
/* Bring kernel and HW constraints together */
|
|
min_sampling_rate = max(min_sampling_rate,
|
|
MIN_LATENCY_MULTIPLIER * latency);
|
|
dbs_tuners_ins.sampling_rate =
|
|
max(min_sampling_rate,
|
|
latency * LATENCY_MULTIPLIER);
|
|
|
|
cpufreq_register_notifier(
|
|
&dbs_cpufreq_notifier_block,
|
|
CPUFREQ_TRANSITION_NOTIFIER);
|
|
}
|
|
dbs_timer_init(this_dbs_info);
|
|
|
|
mutex_unlock(&dbs_mutex);
|
|
|
|
break;
|
|
|
|
case CPUFREQ_GOV_STOP:
|
|
mutex_lock(&dbs_mutex);
|
|
dbs_timer_exit(this_dbs_info);
|
|
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)
|
|
cpufreq_unregister_notifier(
|
|
&dbs_cpufreq_notifier_block,
|
|
CPUFREQ_TRANSITION_NOTIFIER);
|
|
|
|
mutex_unlock(&dbs_mutex);
|
|
|
|
break;
|
|
|
|
case CPUFREQ_GOV_LIMITS:
|
|
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);
|
|
else if (policy->min > this_dbs_info->cur_policy->cur)
|
|
__cpufreq_driver_target(
|
|
this_dbs_info->cur_policy,
|
|
policy->min, CPUFREQ_RELATION_L);
|
|
mutex_unlock(&dbs_mutex);
|
|
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
|
|
static
|
|
#endif
|
|
struct cpufreq_governor cpufreq_gov_conservative = {
|
|
.name = "conservative",
|
|
.governor = cpufreq_governor_dbs,
|
|
.max_transition_latency = TRANSITION_LATENCY_LIMIT,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static int __init cpufreq_gov_dbs_init(void)
|
|
{
|
|
int err;
|
|
|
|
kconservative_wq = create_workqueue("kconservative");
|
|
if (!kconservative_wq) {
|
|
printk(KERN_ERR "Creation of kconservative failed\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
err = cpufreq_register_governor(&cpufreq_gov_conservative);
|
|
if (err)
|
|
destroy_workqueue(kconservative_wq);
|
|
|
|
return err;
|
|
}
|
|
|
|
static void __exit cpufreq_gov_dbs_exit(void)
|
|
{
|
|
cpufreq_unregister_governor(&cpufreq_gov_conservative);
|
|
destroy_workqueue(kconservative_wq);
|
|
}
|
|
|
|
|
|
MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
|
|
MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
|
|
"Low Latency Frequency Transition capable processors "
|
|
"optimised for use in a battery environment");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
|
|
fs_initcall(cpufreq_gov_dbs_init);
|
|
#else
|
|
module_init(cpufreq_gov_dbs_init);
|
|
#endif
|
|
module_exit(cpufreq_gov_dbs_exit);
|