Commit 8c7b09f4 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Ingo Molnar
Browse files

sched: Update the idle statistics in get_cpu_idle_time_us()

Right now, get_cpu_idle_time_us() only reports the idle
statistics upto the point the CPU entered last idle; not what is
valid right now.

This patch adds an update of the idle statistics to
get_cpu_idle_time_us(), so that calling this function always
returns statistics that are accurate at the point of the call.

This includes resetting the start of the idle time for
accounting purposes to avoid double accounting.
Signed-off-by: default avatarArjan van de Ven <>
Signed-off-by: default avatarAndrew Morton <>
Reviewed-by: default avatarRik van Riel <>
Acked-by: default avatarPeter Zijlstra <>
LKML-Reference: <>
Signed-off-by: default avatarIngo Molnar <>
parent 595aac48
......@@ -161,6 +161,7 @@ static void update_ts_time_stats(struct tick_sched *ts, ktime_t now)
if (ts->idle_active) {
delta = ktime_sub(now, ts->idle_entrytime);
ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
ts->idle_entrytime = now;
......@@ -205,14 +206,18 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now;
if (!tick_nohz_enabled)
return -1;
now = ktime_get();
update_ts_time_stats(ts, now);
if (ts->idle_active)
*last_update_time = ktime_to_us(ts->idle_lastupdate);
*last_update_time = ktime_to_us(ktime_get());
*last_update_time = ktime_to_us(now);
return ktime_to_us(ts->idle_sleeptime);
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