src/patches/suse-2.6.27.25/patches.drivers/cpufreq_add_idle_microaccounting_6.patch

   1 From: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   2 Subject: cpufreq,ondemand: Use get_cpu_idle_time_us() to get micro-accounted idle information
   3
   4 Use get_cpu_idle_time_us() to get micro-accounted idle information.
   5 This enables ondemand to get more accurate idle and busy timings
   6 than the jiffy based calculation. As a result, we can decrease
   7 the ondemand safety gaurd band from 80-10 to 95-3.
   8
   9 Results in more aggressive power savings.
  10
  11 Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  12 Signed-off-by: Thomas Renninger <trenn@suse.de>
  13
  14 ---
  15  drivers/cpufreq/cpufreq_ondemand.c |   46 ++++++++++++++++++++++++++++++++++++-
  16  1 file changed, 45 insertions(+), 1 deletion(-)
  17
  18 Index: cpufreq.git/drivers/cpufreq/cpufreq_ondemand.c
  19 ===================================================================
  20 --- cpufreq.git.orig/drivers/cpufreq/cpufreq_ondemand.c 2008-07-31 14:52:15.000000000 -0700
  21 +++ cpufreq.git/drivers/cpufreq/cpufreq_ondemand.c      2008-07-31 14:52:22.000000000 -0700
  22 @@ -18,6 +18,9 @@
  23  #include <linux/jiffies.h>
  24  #include <linux/kernel_stat.h>
  25  #include <linux/mutex.h>
  26 +#include <linux/hrtimer.h>
  27 +#include <linux/tick.h>
  28 +#include <linux/ktime.h>
  29
  30  /*
  31   * dbs is used in this file as a shortform for demandbased switching
  32 @@ -26,6 +29,8 @@
  33
  34  #define DEF_FREQUENCY_DOWN_DIFFERENTIAL                (10)
  35  #define DEF_FREQUENCY_UP_THRESHOLD             (80)
  36 +#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL      (3)
  37 +#define MICRO_FREQUENCY_UP_THRESHOLD           (95)
  38  #define MIN_FREQUENCY_UP_THRESHOLD             (11)
  39  #define MAX_FREQUENCY_UP_THRESHOLD             (100)
  40
  41 @@ -58,6 +63,7 @@ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}
  42  struct cpu_dbs_info_s {
  43         cputime64_t prev_cpu_idle;
  44         cputime64_t prev_cpu_wall;
  45 +       cputime64_t prev_cpu_nice;
  46         struct cpufreq_policy *cur_policy;
  47         struct delayed_work work;
  48         struct cpufreq_frequency_table *freq_table;
  49 @@ -97,7 +103,8 @@ static struct dbs_tuners {
  50         .powersave_bias = 0,
  51  };
  52
  53 -static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
  54 +static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
  55 +                                                       cputime64_t *wall)
  56  {
  57         cputime64_t idle_time;
  58         cputime64_t cur_wall_time;
  59 @@ -123,6 +130,33 @@ static inline cputime64_t get_cpu_idle_t
  60         return idle_time;
  61  }
  62
  63 +static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
  64 +{
  65 +       u64 idle_time = get_cpu_idle_time_us(cpu, wall);
  66 +
  67 +       if (idle_time == -1ULL)
  68 +               return get_cpu_idle_time_jiffy(cpu, wall);
  69 +
  70 +       if (dbs_tuners_ins.ignore_nice) {
  71 +               cputime64_t cur_nice;
  72 +               unsigned long cur_nice_jiffies;
  73 +               struct cpu_dbs_info_s *dbs_info;
  74 +
  75 +               dbs_info = &per_cpu(cpu_dbs_info, cpu);
  76 +               cur_nice = cputime64_sub(kstat_cpu(cpu).cpustat.nice,
  77 +                                        dbs_info->prev_cpu_nice);
  78 +               /*
  79 +                * Assumption: nice time between sampling periods will be
  80 +                * less than 2^32 jiffies for 32 bit sys
  81 +                */
  82 +               cur_nice_jiffies = (unsigned long)
  83 +                                       cputime64_to_jiffies64(cur_nice);
  84 +               dbs_info->prev_cpu_nice = kstat_cpu(cpu).cpustat.nice;
  85 +               return idle_time + jiffies_to_usecs(cur_nice_jiffies);
  86 +       }
  87 +       return idle_time;
  88 +}
  89 +
  90  /*
  91   * Find right freq to be set now with powersave_bias on.
  92   * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
  93 @@ -602,6 +636,16 @@ EXPORT_SYMBOL(cpufreq_gov_ondemand);
  94
  95  static int __init cpufreq_gov_dbs_init(void)
  96  {
  97 +       cputime64_t wall;
  98 +       u64 idle_time = get_cpu_idle_time_us(smp_processor_id(), &wall);
  99 +
 100 +       if (idle_time != -1ULL) {
 101 +               /* Idle micro accounting is supported. Use finer thresholds */
 102 +               dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
 103 +               dbs_tuners_ins.down_differential =
 104 +                                       MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
 105 +       }
 106 +
 107         kondemand_wq = create_workqueue("kondemand");
 108         if (!kondemand_wq) {
 109                 printk(KERN_ERR "Creation of kondemand failed\n");
 110
 111 --