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[CPUFREQ] conservative: fixup governor to function more like ondemand logic

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As conservative is based off ondemand the codebases occasionally need to be
resync'd.  This patch, although ugly, does this.

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
Signed-off-by: Dave Jones <davej@redhat.com>
tirimbino
Alexander Clouter 16 years ago committed by Dave Jones
parent f407a08bb7
commit 8e677ce83b
1 changed files with 188 additions and 140 deletions
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  1. 328
      drivers/cpufreq/cpufreq_conservative.c

328
drivers/cpufreq/cpufreq_conservative.c
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@ -13,22 +13,17 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ctype.h>
#include <linux/cpufreq.h>
#include <linux/sysctl.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/cpu.h>
#include <linux/kmod.h>
#include <linux/workqueue.h>
#include <linux/jiffies.h>
#include <linux/kernel_stat.h>
#include <linux/percpu.h>
#include <linux/mutex.h>
#include <linux/hrtimer.h>
#include <linux/tick.h>
#include <linux/ktime.h>
#include <linux/sched.h>
/*
* dbs is used in this file as a shortform for demandbased switching
* It helps to keep variable names smaller, simpler
@ -43,14 +38,14 @@
* latency of the processor. The governor will work on any processor with
* transition latency <= 10mS, using appropriate sampling
* rate.
* For CPUs with transition latency > 10mS (mostly drivers
* with CPUFREQ_ETERNAL), this governor will not work.
* For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
* this governor will not work.
* All times here are in uS.
*/
static unsigned int def_sampling_rate;
#define MIN_SAMPLING_RATE_RATIO (2)
/* for correct statistics, we need at least 10 ticks between each measure */
#define MIN_STAT_SAMPLING_RATE \
#define MIN_STAT_SAMPLING_RATE \
(MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
#define MIN_SAMPLING_RATE \
(def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
@ -75,12 +70,15 @@ static unsigned int minimum_sampling_rate(void)
static void do_dbs_timer(struct work_struct *work);
struct cpu_dbs_info_s {
cputime64_t prev_cpu_idle;
cputime64_t prev_cpu_wall;
cputime64_t prev_cpu_nice;
struct cpufreq_policy *cur_policy;
unsigned int prev_cpu_idle_up;
unsigned int prev_cpu_idle_down;
unsigned int enable;
struct delayed_work work;
unsigned int down_skip;
unsigned int requested_freq;
int cpu;
unsigned int enable:1;
};
static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
@ -95,18 +93,17 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */
* is recursive for the same process. -Venki
*/
static DEFINE_MUTEX(dbs_mutex);
static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer);
struct dbs_tuners {
static struct workqueue_struct *kconservative_wq;
static struct dbs_tuners {
unsigned int sampling_rate;
unsigned int sampling_down_factor;
unsigned int up_threshold;
unsigned int down_threshold;
unsigned int ignore_nice;
unsigned int freq_step;
};
static struct dbs_tuners dbs_tuners_ins = {
} dbs_tuners_ins = {
.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
.down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
@ -114,18 +111,37 @@ static struct dbs_tuners dbs_tuners_ins = {
.freq_step = 5,
};
static inline unsigned int get_cpu_idle_time(unsigned int cpu)
static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
cputime64_t *wall)
{
unsigned int add_nice = 0, ret;
cputime64_t idle_time;
cputime64_t cur_wall_time;
cputime64_t busy_time;
cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
kstat_cpu(cpu).cpustat.system);
if (dbs_tuners_ins.ignore_nice)
add_nice = kstat_cpu(cpu).cpustat.nice;
busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);
busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);
busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);
busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);
ret = kstat_cpu(cpu).cpustat.idle +
kstat_cpu(cpu).cpustat.iowait +
add_nice;
idle_time = cputime64_sub(cur_wall_time, busy_time);
if (wall)
*wall = cur_wall_time;
return ret;
return idle_time;
}
static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
{
u64 idle_time = get_cpu_idle_time_us(cpu, wall);
if (idle_time == -1ULL)
return get_cpu_idle_time_jiffy(cpu, wall);
return idle_time;
}
/* keep track of frequency transitions */
@ -186,8 +202,8 @@ static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
return sprintf(buf, "%u\n", MIN_SAMPLING_RATE);
}
#define define_one_ro(_name) \
static struct freq_attr _name = \
#define define_one_ro(_name) \
static struct freq_attr _name = \
__ATTR(_name, 0444, show_##_name, NULL)
define_one_ro(sampling_rate_max);
@ -213,6 +229,7 @@ static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
unsigned int input;
int ret;
ret = sscanf(buf, "%u", &input);
if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
return -EINVAL;
@ -230,11 +247,10 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
int ret;
ret = sscanf(buf, "%u", &input);
mutex_lock(&dbs_mutex);
if (ret != 1) {
mutex_unlock(&dbs_mutex);
if (ret != 1)
return -EINVAL;
}
mutex_lock(&dbs_mutex);
dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate());
mutex_unlock(&dbs_mutex);
@ -250,7 +266,7 @@ static ssize_t store_up_threshold(struct cpufreq_policy *unused,
mutex_lock(&dbs_mutex);
if (ret != 1 || input > 100 ||
input <= dbs_tuners_ins.down_threshold) {
input <= dbs_tuners_ins.down_threshold) {
mutex_unlock(&dbs_mutex);
return -EINVAL;
}
@ -269,7 +285,9 @@ static ssize_t store_down_threshold(struct cpufreq_policy *unused,
ret = sscanf(buf, "%u", &input);
mutex_lock(&dbs_mutex);
if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) {
/* cannot be lower than 11 otherwise freq will not fall */
if (ret != 1 || input < 11 || input > 100 ||
input >= dbs_tuners_ins.up_threshold) {
mutex_unlock(&dbs_mutex);
return -EINVAL;
}
@ -302,12 +320,14 @@ 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);
if (dbs_tuners_ins.ignore_nice)
dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
}
mutex_unlock(&dbs_mutex);
@ -319,7 +339,6 @@ static ssize_t store_freq_step(struct cpufreq_policy *policy,
{
unsigned int input;
int ret;
ret = sscanf(buf, "%u", &input);
if (ret != 1)
@ -367,55 +386,78 @@ 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, up_idle_ticks, down_idle_ticks;
unsigned int tmp_idle_ticks, total_idle_ticks;
unsigned int load = 0;
unsigned int freq_target;
unsigned int freq_down_sampling_rate;
struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
struct cpufreq_policy *policy;
if (!this_dbs_info->enable)
return;
struct cpufreq_policy *policy;
unsigned int j;
policy = this_dbs_info->cur_policy;
/*
* The default safe range is 20% to 80%
* Every sampling_rate, we check
* - If current idle time is less than 20%, then we try to
* increase frequency
* Every sampling_rate*sampling_down_factor, we check
* - If current idle time is more than 80%, then we try to
* decrease frequency
* 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 check, if current
* idle time is more than 80%, then we try to decrease frequency
*
* Any frequency increase takes it to the maximum frequency.
* Frequency reduction happens at minimum steps of
* 5% (default) of max_frequency
* 5% (default) of maximum frequency
*/
/* Check for frequency increase */
idle_ticks = UINT_MAX;
/* Get Absolute Load */
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info_s *j_dbs_info;
cputime64_t cur_wall_time, cur_idle_time;
unsigned int idle_time, wall_time;
/* Check for frequency increase */
total_idle_ticks = get_cpu_idle_time(cpu);
tmp_idle_ticks = total_idle_ticks -
this_dbs_info->prev_cpu_idle_up;
this_dbs_info->prev_cpu_idle_up = total_idle_ticks;
j_dbs_info = &per_cpu(cpu_dbs_info, j);
cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
wall_time = (unsigned int) cputime64_sub(cur_wall_time,
j_dbs_info->prev_cpu_wall);
j_dbs_info->prev_cpu_wall = cur_wall_time;
if (tmp_idle_ticks < idle_ticks)
idle_ticks = tmp_idle_ticks;
idle_time = (unsigned int) cputime64_sub(cur_idle_time,
j_dbs_info->prev_cpu_idle);
j_dbs_info->prev_cpu_idle = cur_idle_time;
/* 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 (dbs_tuners_ins.ignore_nice) {
cputime64_t cur_nice;
unsigned long cur_nice_jiffies;
cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,
j_dbs_info->prev_cpu_nice);
/*
* Assumption: nice time between sampling periods will
* be less than 2^32 jiffies for 32 bit sys
*/
cur_nice_jiffies = (unsigned long)
cputime64_to_jiffies64(cur_nice);
j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
idle_time += jiffies_to_usecs(cur_nice_jiffies);
}
if (unlikely(!wall_time || wall_time < idle_time))
continue;
load = 100 * (wall_time - idle_time) / wall_time;
}
/*
* break out if we 'cannot' reduce the speed as the user might
* want freq_step to be zero
*/
if (dbs_tuners_ins.freq_step == 0)
return;
if (idle_ticks < up_idle_ticks) {
/* Check for frequency increase */
if (load > dbs_tuners_ins.up_threshold) {
this_dbs_info->down_skip = 0;
this_dbs_info->prev_cpu_idle_down =
this_dbs_info->prev_cpu_idle_up;
/* if we are already at full speed then break out early */
if (this_dbs_info->requested_freq == policy->max)
@ -436,49 +478,24 @@ static void dbs_check_cpu(int cpu)
return;
}
/* Check for frequency decrease */
this_dbs_info->down_skip++;
if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor)
return;
/* Check for frequency decrease */
total_idle_ticks = this_dbs_info->prev_cpu_idle_up;
tmp_idle_ticks = total_idle_ticks -
this_dbs_info->prev_cpu_idle_down;
this_dbs_info->prev_cpu_idle_down = total_idle_ticks;
if (tmp_idle_ticks < idle_ticks)
idle_ticks = tmp_idle_ticks;
/* Scale idle ticks by 100 and compare with up and down ticks */
idle_ticks *= 100;
this_dbs_info->down_skip = 0;
freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *
dbs_tuners_ins.sampling_down_factor;
down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) *
usecs_to_jiffies(freq_down_sampling_rate);
if (idle_ticks > down_idle_ticks) {
/*
* if we are already at the lowest speed then break out early
* or if we 'cannot' reduce the speed as the user might want
* freq_target to be zero
*/
if (this_dbs_info->requested_freq == policy->min
|| dbs_tuners_ins.freq_step == 0)
return;
/*
* 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.
*/
if (load < (dbs_tuners_ins.down_threshold - 10)) {
freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
/* max freq cannot be less than 100. But who knows.... */
if (unlikely(freq_target == 0))
freq_target = 5;
this_dbs_info->requested_freq -= freq_target;
if (this_dbs_info->requested_freq < policy->min)
this_dbs_info->requested_freq = policy->min;
/*
* if we cannot reduce the frequency anymore, break out early
*/
if (policy->cur == policy->min)
return;
__cpufreq_driver_target(policy, this_dbs_info->requested_freq,
CPUFREQ_RELATION_H);
return;
@ -487,27 +504,45 @@ static void dbs_check_cpu(int cpu)
static void do_dbs_timer(struct work_struct *work)
{
int i;
mutex_lock(&dbs_mutex);
for_each_online_cpu(i)
dbs_check_cpu(i);
schedule_delayed_work(&dbs_work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
mutex_unlock(&dbs_mutex);
struct cpu_dbs_info_s *dbs_info =
container_of(work, struct cpu_dbs_info_s, work.work);
unsigned int cpu = dbs_info->cpu;
/* We want all CPUs to do sampling nearly on same jiffy */
int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
delay -= jiffies % delay;
if (lock_policy_rwsem_write(cpu) < 0)
return;
if (!dbs_info->enable) {
unlock_policy_rwsem_write(cpu);
return;
}
dbs_check_cpu(dbs_info);
queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);
unlock_policy_rwsem_write(cpu);
}
static inline void dbs_timer_init(void)
static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
{
init_timer_deferrable(&dbs_work.timer);
schedule_delayed_work(&dbs_work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
return;
/* 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(void)
static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
{
cancel_delayed_work(&dbs_work);
return;
dbs_info->enable = 0;
cancel_delayed_work(&dbs_info->work);
}
static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
@ -541,11 +576,13 @@ 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(cpu);
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);
if (dbs_tuners_ins.ignore_nice) {
j_dbs_info->prev_cpu_nice =
kstat_cpu(j).cpustat.nice;
}
}
this_dbs_info->enable = 1;
this_dbs_info->down_skip = 0;
this_dbs_info->requested_freq = policy->cur;
@ -567,30 +604,30 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
dbs_tuners_ins.sampling_rate = def_sampling_rate;
dbs_timer_init();
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);
this_dbs_info->enable = 0;
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) {
dbs_timer_exit();
if (dbs_enable == 0)
cpufreq_unregister_notifier(
&dbs_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
}
mutex_unlock(&dbs_mutex);
@ -607,6 +644,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
this_dbs_info->cur_policy,
policy->min, CPUFREQ_RELATION_L);
mutex_unlock(&dbs_mutex);
break;
}
return 0;
@ -624,15 +662,25 @@ struct cpufreq_governor cpufreq_gov_conservative = {
static int __init cpufreq_gov_dbs_init(void)
{
return cpufreq_register_governor(&cpufreq_gov_conservative);
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)
{
/* Make sure that the scheduled work is indeed not running */
flush_scheduled_work();
cpufreq_unregister_governor(&cpufreq_gov_conservative);
destroy_workqueue(kconservative_wq);
}

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