[CPUFREQ][3/6] cpufreq: get_cpu_idle_time() changes in ondemand for idle-microaccounting

Preparatory changes for doing idle micro-accounting in ondemand governor.
get_cpu_idle_time() gets extra parameter and returns idle time and also the
wall time that corresponds to the idle time measurement.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 42fcb14..b935092 100644 (file)
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -94,13 +94,13 @@ static struct dbs_tuners {
        .powersave_bias = 0,
 };
 
-static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
+static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
 {
        cputime64_t idle_time;
-       cputime64_t cur_jiffies;
+       cputime64_t cur_wall_time;
        cputime64_t busy_time;
 
-       cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
+       cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
        busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
                        kstat_cpu(cpu).cpustat.system);
 
@@ -113,7 +113,10 @@ static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
                                kstat_cpu(cpu).cpustat.nice);
        }
 
-       idle_time = cputime64_sub(cur_jiffies, busy_time);
+       idle_time = cputime64_sub(cur_wall_time, busy_time);
+       if (wall)
+               *wall = cur_wall_time;
+
        return idle_time;
 }
 
@@ -277,8 +280,8 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
        for_each_online_cpu(j) {
                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 = get_jiffies_64();
+               dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
+                                               &dbs_info->prev_cpu_wall);
        }
        mutex_unlock(&dbs_mutex);
 
@@ -368,21 +371,19 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
                int freq_avg;
 
                j_dbs_info = &per_cpu(cpu_dbs_info, j);
-               cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
+
+               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;
 
-               cur_idle_time = get_cpu_idle_time(j);
                idle_time = (unsigned int) cputime64_sub(cur_idle_time,
                                j_dbs_info->prev_cpu_idle);
                j_dbs_info->prev_cpu_idle = cur_idle_time;
 
-               if (unlikely(wall_time <= idle_time ||
-                            (cputime_to_msecs(wall_time) <
-                             dbs_tuners_ins.sampling_rate / (2 * 1000)))) {
+               if (unlikely(!wall_time || wall_time < idle_time))
                        continue;
-               }
 
                load = 100 * (wall_time - idle_time) / wall_time;
 
@@ -531,8 +532,8 @@ 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 = get_cpu_idle_time(j);
-                       j_dbs_info->prev_cpu_wall = get_jiffies_64();
+                       j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
+                                               &j_dbs_info->prev_cpu_wall);
                }
                this_dbs_info->cpu = cpu;
                /*