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authorArjan van de Ven <arjan@linux.intel.com>2010-05-09 17:23:23 +0200
committerIngo Molnar <mingo@elte.hu>2010-05-09 19:35:26 +0200
commit8c7b09f43f4bf570654bcc458ce96819a932303c (patch)
tree33eb6f860fa9a31ea63b67247890a6762439fde2 /kernel/time/tick-sched.c
parentsched: Introduce a function to update the idle statistics (diff)
downloadlinux-8c7b09f43f4bf570654bcc458ce96819a932303c.tar.xz
linux-8c7b09f43f4bf570654bcc458ce96819a932303c.zip
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: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082323.2d2f1945@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/time/tick-sched.c')
-rw-r--r--kernel/time/tick-sched.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 59d8762c7e1d..f15d18d82c18 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -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);
else
- *last_update_time = ktime_to_us(ktime_get());
+ *last_update_time = ktime_to_us(now);
return ktime_to_us(ts->idle_sleeptime);
}