Commit b1f724c3 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Ingo Molnar
Browse files

sched: Add a comment to get_cpu_idle_time_us()



The exported function get_cpu_idle_time_us() has no comment
describing it; add a kerneldoc comment
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082208.7cb721f0@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e7858f52
......@@ -179,6 +179,20 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
return now;
}
/**
* get_cpu_idle_time_us - get the total idle time of a cpu
* @cpu: CPU number to query
* @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).
*
* This time is measured via accounting rather than sampling,
* and is as accurate as ktime_get() is.
*
* This function returns -1 if NOHZ is not enabled.
*/
u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
......
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