Commit 6beea0cd authored by Michal Hocko's avatar Michal Hocko Committed by Thomas Gleixner

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: default avatarMichal 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.czSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent ef0e0f5e
...@@ -120,10 +120,12 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, ...@@ -120,10 +120,12 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
{ {
u64 idle_time = get_cpu_idle_time_us(cpu, wall); u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
if (idle_time == -1ULL) if (idle_time == -1ULL)
return get_cpu_idle_time_jiffy(cpu, wall); return get_cpu_idle_time_jiffy(cpu, wall);
else
idle_time += get_cpu_iowait_time_us(cpu, wall);
return idle_time; return idle_time;
} }
......
...@@ -144,10 +144,12 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, ...@@ -144,10 +144,12 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
{ {
u64 idle_time = get_cpu_idle_time_us(cpu, wall); u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
if (idle_time == -1ULL) if (idle_time == -1ULL)
return get_cpu_idle_time_jiffy(cpu, wall); return get_cpu_idle_time_jiffy(cpu, wall);
else
idle_time += get_cpu_iowait_time_us(cpu, wall);
return idle_time; return idle_time;
} }
......
...@@ -159,9 +159,10 @@ update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_upda ...@@ -159,9 +159,10 @@ update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_upda
if (ts->idle_active) { if (ts->idle_active) {
delta = ktime_sub(now, ts->idle_entrytime); delta = ktime_sub(now, ts->idle_entrytime);
ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
if (nr_iowait_cpu(cpu) > 0) if (nr_iowait_cpu(cpu) > 0)
ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta);
else
ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
ts->idle_entrytime = now; ts->idle_entrytime = now;
} }
...@@ -200,8 +201,7 @@ static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts) ...@@ -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 * @last_update_time: variable to store update time in
* *
* Return the cummulative idle time (since boot) for a given * Return the cummulative idle time (since boot) for a given
* CPU, in microseconds. The idle time returned includes * CPU, in microseconds.
* the iowait time (unlike what "top" and co report).
* *
* This time is measured via accounting rather than sampling, * This time is measured via accounting rather than sampling,
* and is as accurate as ktime_get() is. * and is as accurate as ktime_get() is.
...@@ -221,7 +221,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) ...@@ -221,7 +221,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
} }
EXPORT_SYMBOL_GPL(get_cpu_idle_time_us); EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
/* /**
* get_cpu_iowait_time_us - get the total iowait time of a cpu * get_cpu_iowait_time_us - get the total iowait time of a cpu
* @cpu: CPU number to query * @cpu: CPU number to query
* @last_update_time: variable to store update time in * @last_update_time: variable to store update time in
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment