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| author | venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> | 2008-08-04 20:59:12 +0200 |
|---|---|---|
| committer | Dave Jones <davej@redhat.com> | 2008-10-09 19:52:44 +0200 |
| commit | 808009131046b62ac434dbc796c0fe8accaab415 (patch) | |
| tree | 64b5c755b8eb5d43f8e00554032de372f36e7b4c /drivers/cpufreq/cpufreq_ondemand.c | |
| parent | [CPUFREQ][5/6] cpufreq: Changes to get_cpu_idle_time_us(), used by ondemand g... (diff) | |
| download | linux-808009131046b62ac434dbc796c0fe8accaab415.tar.xz linux-808009131046b62ac434dbc796c0fe8accaab415.zip | |
[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: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers/cpufreq/cpufreq_ondemand.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq_ondemand.c | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 3f898606e68c..39253d6d51ef 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -18,6 +18,9 @@ #include <linux/jiffies.h> #include <linux/kernel_stat.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 @@ -26,6 +29,8 @@ #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) #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 MAX_FREQUENCY_UP_THRESHOLD (100) @@ -58,6 +63,7 @@ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; 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; struct delayed_work work; struct cpufreq_frequency_table *freq_table; @@ -97,7 +103,8 @@ static struct dbs_tuners { .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 cur_wall_time; @@ -123,6 +130,33 @@ static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) 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. * Returns the freq_hi to be used right now and will set freq_hi_jiffies, @@ -603,6 +637,15 @@ EXPORT_SYMBOL(cpufreq_gov_ondemand); static int __init cpufreq_gov_dbs_init(void) { 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"); if (!kondemand_wq) { |