time: track accurate idle time with tick_sched.idle_sleeptime

[linux-2.6-omap-h63xx.git] / kernel / time / tick-sched.c

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 49e12f6a4bab8229e5a4aaed7a2a818163dc5432..63f24b55069551f4331f09c090657b66be139f7e 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -143,6 +143,44 @@ void tick_nohz_update_jiffies(void)
        local_irq_restore(flags);
 }
 
+void tick_nohz_stop_idle(int cpu)
+{
+       struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+       if (ts->idle_active) {
+               ktime_t now, delta;
+               now = ktime_get();
+               delta = ktime_sub(now, ts->idle_entrytime);
+               ts->idle_lastupdate = now;
+               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+               ts->idle_active = 0;
+       }
+}
+
+static ktime_t tick_nohz_start_idle(int cpu)
+{
+       struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+       ktime_t now, delta;
+
+       now = ktime_get();
+       if (ts->idle_active) {
+               delta = ktime_sub(now, ts->idle_entrytime);
+               ts->idle_lastupdate = now;
+               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+       }
+       ts->idle_entrytime = now;
+       ts->idle_active = 1;
+       return now;
+}
+
+u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
+{
+       struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+       *last_update_time = ktime_to_us(ts->idle_lastupdate);
+       return ktime_to_us(ts->idle_sleeptime);
+}
+
 /**
  * tick_nohz_stop_sched_tick - stop the idle tick from the idle task
  *
@@ -155,13 +193,14 @@ void tick_nohz_stop_sched_tick(void)
        unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
        unsigned long rt_jiffies;
        struct tick_sched *ts;
-       ktime_t last_update, expires, now, delta;
+       ktime_t last_update, expires, now;
        struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
        int cpu;
 
        local_irq_save(flags);
 
        cpu = smp_processor_id();
+       now = tick_nohz_start_idle(cpu);
        ts = &per_cpu(tick_cpu_sched, cpu);
 
        /*
@@ -193,19 +232,7 @@ void tick_nohz_stop_sched_tick(void)
                }
        }
 
-       now = ktime_get();
-       /*
-        * When called from irq_exit we need to account the idle sleep time
-        * correctly.
-        */
-       if (ts->tick_stopped) {
-               delta = ktime_sub(now, ts->idle_entrytime);
-               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-       }
-
-       ts->idle_entrytime = now;
        ts->idle_calls++;
-
        /* Read jiffies and the time when jiffies were updated last */
        do {
                seq = read_seqbegin(&xtime_lock);
@@ -337,23 +364,22 @@ void tick_nohz_restart_sched_tick(void)
        int cpu = smp_processor_id();
        struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
        unsigned long ticks;
-       ktime_t now, delta;
+       ktime_t now;
 
-       if (!ts->tick_stopped)
+       local_irq_disable();
+       tick_nohz_stop_idle(cpu);
+
+       if (!ts->tick_stopped) {
+               local_irq_enable();
                return;
+       }
 
        /* Update jiffies first */
-       now = ktime_get();
-
-       local_irq_disable();
        select_nohz_load_balancer(0);
+       now = ktime_get();
        tick_do_update_jiffies64(now);
        cpu_clear(cpu, nohz_cpu_mask);
 
-       /* Account the idle time */
-       delta = ktime_sub(now, ts->idle_entrytime);
-       ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-
        /*
         * We stopped the tick in idle. Update process times would miss the
         * time we slept as update_process_times does only a 1 tick