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From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Frédéric Weisbecker" <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lists linaro-kernel <linaro-kernel@lists.linaro.org>
Subject: [Query]: tick-sched: why don't we stop tick when we are running idle task?
Date: Wed, 9 Apr 2014 16:03:00 +0530	[thread overview]
Message-ID: <CAKohpo=uT0oC+bZVJQPsoGLb-a4y4huYKtd1ayb4_+iH4906nw@mail.gmail.com> (raw)

Hi Frederic,

File: kernel/time/tick-sched.c
Function: tick_nohz_full_stop_tick()

We are doing this:

if (!tick_nohz_full_cpu(cpu) || is_idle_task(current))
        return;

Which means: if a FULL_NO_HZ cpu is running idle task currently,
don't stop its tick..

I couldn't understand why. Can you please help here?

--
viresh

             reply	other threads:[~2014-04-09 10:33 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-09 10:33 Viresh Kumar [this message]
2014-04-09 10:49 ` [Query]: tick-sched: why don't we stop tick when we are running idle task? Viresh Kumar
2014-04-10 14:39   ` Frederic Weisbecker
2014-04-11 10:04     ` Viresh Kumar
2014-04-11 14:53       ` Frederic Weisbecker
2014-04-11 15:18         ` Peter Zijlstra
2014-04-11 16:38           ` Viresh Kumar
2014-04-14  9:48             ` Preeti Murthy
2014-04-14  9:51               ` Viresh Kumar
2014-04-14 11:02             ` Peter Zijlstra
2014-04-14 11:42               ` Viresh Kumar
2014-04-14 11:47                 ` Peter Zijlstra
2014-04-14 11:52                   ` Viresh Kumar
2014-04-14 12:06                     ` Peter Zijlstra
2014-04-15  6:04                       ` Viresh Kumar
2014-04-15  9:30                       ` Frederic Weisbecker
2014-04-15 10:52                         ` Peter Zijlstra
2014-04-15 10:53                           ` Peter Zijlstra
2014-04-23 11:12                         ` Viresh Kumar
2014-05-09  8:44                           ` Viresh Kumar
2014-05-13 23:30                             ` Frederic Weisbecker
2014-05-22  8:44                               ` Peter Zijlstra

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