From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753613Ab0EIPYW (ORCPT ); Sun, 9 May 2010 11:24:22 -0400 Received: from casper.infradead.org ([85.118.1.10]:40362 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752984Ab0EIPYR (ORCPT ); Sun, 9 May 2010 11:24:17 -0400 Date: Sun, 9 May 2010 08:22:08 -0700 From: Arjan van de Ven To: Arjan van de Ven Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, davej@redhat.com Subject: [PATCH v2 1/8] sched: Add a comment to get_cpu_idle_time_us() Message-ID: <20100509082208.7cb721f0@infradead.org> In-Reply-To: <20100509082126.4a080d46@infradead.org> References: <20100509082126.4a080d46@infradead.org> Organization: Intel X-Mailer: Claws Mail 3.7.5 (GTK+ 2.16.6; i586-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arjan van de Ven The exported function get_cpu_idle_time_us() has no comment describing it; add a kerneldoc comment Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Reviewed-by: Rik van Riel --- 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); _