Messages in this thread Patch in this message | | | Date | Sun, 9 May 2010 08:22:08 -0700 | From | Arjan van de Ven <> | Subject | [PATCH v2 1/8] sched: Add a comment to get_cpu_idle_time_us() |
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From: Arjan van de Ven <arjan@linux.intel.com>
The exported function get_cpu_idle_time_us() has no comment describing it; add a kerneldoc comment
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>
---
kernel/time/tick-sched.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff -puN kernel/time/tick-sched.c~sched-add-a-comment-to-get_cpu_idle_time_us kernel/time/tick-sched.c --- a/kernel/time/tick-sched.c~sched-add-a-comment-to-get_cpu_idle_time_us +++ a/kernel/time/tick-sched.c @@ -179,6 +179,20 @@ static ktime_t tick_nohz_start_idle(stru 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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