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| author | Michal Hocko <mhocko@suse.cz> | 2011-08-24 09:37:48 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-09-08 11:10:55 +0200 |
| commit | 6beea0cda8ce71c01354e688e5735c47e331e84f (patch) | |
| tree | 7556787053d608134184d98413cce744d54507fc /kernel/time | |
| parent | ef0e0f5ed9bde6d1e3376169785a463ad2160e6d (diff) | |
| download | blackbird-obmc-linux-6beea0cda8ce71c01354e688e5735c47e331e84f.tar.gz blackbird-obmc-linux-6beea0cda8ce71c01354e688e5735c47e331e84f.zip | |
nohz: Fix update_ts_time_stat idle accounting
update_ts_time_stat currently updates idle time even if we are in
iowait loop at the moment. The only real users of the idle counter
(via get_cpu_idle_time_us) are CPU governors and they expect to get
cumulative time for both idle and iowait times.
The value (idle_sleeptime) is also printed to userspace by print_cpu
but it prints both idle and iowait times so the idle part is misleading.
Let's clean this up and fix update_ts_time_stat to account both counters
properly and update consumers of idle to consider iowait time as well.
If we do this we might use get_cpu_{idle,iowait}_time_us from other
contexts as well and we will get expected values.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Jones <davej@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Link: http://lkml.kernel.org/r/e9c909c221a8da402c4da07e4cd968c3218f8eb1.1314172057.git.mhocko@suse.cz
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/tick-sched.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d5097c44b407..7ab44bca6546 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -159,9 +159,10 @@ update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_upda if (ts->idle_active) { delta = ktime_sub(now, ts->idle_entrytime); - ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); if (nr_iowait_cpu(cpu) > 0) ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); + else + ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); ts->idle_entrytime = now; } @@ -200,8 +201,7 @@ static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts) * @last_update_time: variable to store update time in * * Return the cummulative idle time (since boot) for a given - * CPU, in microseconds. The idle time returned includes - * the iowait time (unlike what "top" and co report). + * CPU, in microseconds. * * This time is measured via accounting rather than sampling, * and is as accurate as ktime_get() is. @@ -221,7 +221,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) } EXPORT_SYMBOL_GPL(get_cpu_idle_time_us); -/* +/** * get_cpu_iowait_time_us - get the total iowait time of a cpu * @cpu: CPU number to query * @last_update_time: variable to store update time in |
