Commit 80800913 authored by venkatesh.pallipadi@intel.com's avatar venkatesh.pallipadi@intel.com Committed by Dave Jones

[CPUFREQ][6/6] cpufreq: Add idle microaccounting in ondemand governor

Use get_cpu_idle_time_us() to get micro-accounted idle information.
This enables ondemand to get more accurate idle and busy timings
than the jiffy based calculation. As a result, we can decrease
the ondemand safety gaurd band from 80-10 to 95-3.

Results in more aggressive power savings.
Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 8083e4ad
...@@ -18,6 +18,9 @@ ...@@ -18,6 +18,9 @@
#include <linux/jiffies.h> #include <linux/jiffies.h>
#include <linux/kernel_stat.h> #include <linux/kernel_stat.h>
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/hrtimer.h>
#include <linux/tick.h>
#include <linux/ktime.h>
/* /*
* dbs is used in this file as a shortform for demandbased switching * dbs is used in this file as a shortform for demandbased switching
...@@ -26,6 +29,8 @@ ...@@ -26,6 +29,8 @@
#define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10)
#define DEF_FREQUENCY_UP_THRESHOLD (80) #define DEF_FREQUENCY_UP_THRESHOLD (80)
#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3)
#define MICRO_FREQUENCY_UP_THRESHOLD (95)
#define MIN_FREQUENCY_UP_THRESHOLD (11) #define MIN_FREQUENCY_UP_THRESHOLD (11)
#define MAX_FREQUENCY_UP_THRESHOLD (100) #define MAX_FREQUENCY_UP_THRESHOLD (100)
...@@ -58,6 +63,7 @@ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; ...@@ -58,6 +63,7 @@ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
struct cpu_dbs_info_s { struct cpu_dbs_info_s {
cputime64_t prev_cpu_idle; cputime64_t prev_cpu_idle;
cputime64_t prev_cpu_wall; cputime64_t prev_cpu_wall;
cputime64_t prev_cpu_nice;
struct cpufreq_policy *cur_policy; struct cpufreq_policy *cur_policy;
struct delayed_work work; struct delayed_work work;
struct cpufreq_frequency_table *freq_table; struct cpufreq_frequency_table *freq_table;
...@@ -97,7 +103,8 @@ static struct dbs_tuners { ...@@ -97,7 +103,8 @@ static struct dbs_tuners {
.powersave_bias = 0, .powersave_bias = 0,
}; };
static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
cputime64_t *wall)
{ {
cputime64_t idle_time; cputime64_t idle_time;
cputime64_t cur_wall_time; cputime64_t cur_wall_time;
...@@ -123,6 +130,33 @@ static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) ...@@ -123,6 +130,33 @@ static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
return idle_time; 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);
if (dbs_tuners_ins.ignore_nice) {
cputime64_t cur_nice;
unsigned long cur_nice_jiffies;
struct cpu_dbs_info_s *dbs_info;
dbs_info = &per_cpu(cpu_dbs_info, cpu);
cur_nice = cputime64_sub(kstat_cpu(cpu).cpustat.nice,
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);
dbs_info->prev_cpu_nice = kstat_cpu(cpu).cpustat.nice;
return idle_time + jiffies_to_usecs(cur_nice_jiffies);
}
return idle_time;
}
/* /*
* Find right freq to be set now with powersave_bias on. * Find right freq to be set now with powersave_bias on.
* Returns the freq_hi to be used right now and will set freq_hi_jiffies, * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
...@@ -603,6 +637,15 @@ EXPORT_SYMBOL(cpufreq_gov_ondemand); ...@@ -603,6 +637,15 @@ EXPORT_SYMBOL(cpufreq_gov_ondemand);
static int __init cpufreq_gov_dbs_init(void) static int __init cpufreq_gov_dbs_init(void)
{ {
int err; int err;
cputime64_t wall;
u64 idle_time = get_cpu_idle_time_us(smp_processor_id(), &wall);
if (idle_time != -1ULL) {
/* Idle micro accounting is supported. Use finer thresholds */
dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
dbs_tuners_ins.down_differential =
MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
}
kondemand_wq = create_workqueue("kondemand"); kondemand_wq = create_workqueue("kondemand");
if (!kondemand_wq) { if (!kondemand_wq) {
......
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