From: Viresh Kumar <viresh.kumar@linaro.org>
To: Mason <slash.tmp@free.fr>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Mans Rullgard <mans@mansr.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux PM <linux-pm@vger.kernel.org>,
cpufreq <cpufreq@vger.kernel.org>
Subject: Re: schedule_timeout sleeps too long after dividing CPU frequency
Date: Thu, 14 May 2015 07:43:28 +0530 [thread overview]
Message-ID: <CAOh2x==aCLxCWX9K57hOFVEP1eLo_OYZPe0YvbFvpkXcoSp_hQ@mail.gmail.com> (raw)
In-Reply-To: <555380F8.5050306@free.fr>
On Wed, May 13, 2015 at 10:21 PM, Mason <slash.tmp@free.fr> wrote:
> $ git diff v3.14.41 HEAD >tango.patch && xz tango.patch
>
> I don't understand the IRQ-related part yet
> ( arch/arm/mach-tangox/irq.c and drivers/irqchip/irq-gic.c )
>
> If anyone spots the problem, that would make my day.
>
> I tested with a loadable module whose init function is
>
> static int __init ts_init(void)
> {
> long res;
> printk("ABOUT TO SLEEP\n");
> set_current_state(TASK_INTERRUPTIBLE);
> res = schedule_timeout(HZ);
> printk("WAKE UP res=%ld\n", res);
> return 0;
> }
>
> Loading the module, with cpufreq divided by 9, prints:
> [ 1738.962982] ABOUT TO SLEEP
> [ 1747.956191] WAKE UP res=0
I hope you are also matching this time with a physical watch,
to make sure 38->47 is really 9 seconds :)
next prev parent reply other threads:[~2015-05-14 2:13 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-12 14:32 schedule_timeout sleeps too long after dividing CPU frequency Mason
2015-05-12 14:46 ` Viresh Kumar
2015-05-12 15:14 ` Mason
2015-05-12 15:50 ` Russell King - ARM Linux
2015-05-12 16:14 ` Mason
2015-05-13 16:51 ` Mason
2015-05-14 2:13 ` Viresh Kumar [this message]
2015-05-14 11:22 ` Mason
2015-05-14 11:54 ` Viresh Kumar
2015-05-14 13:06 ` Mason
2015-05-14 13:53 ` Russell King - ARM Linux
2015-05-14 14:51 ` Mason
2015-05-14 13:59 ` Viresh Kumar
2015-05-14 14:38 ` Viresh Kumar
2015-05-14 14:42 ` Russell King - ARM Linux
2015-05-15 9:29 ` Mason
2015-05-15 9:51 ` Russell King - ARM Linux
2015-05-15 10:01 ` Viresh Kumar
2015-05-15 10:36 ` Mason
2015-05-15 11:58 ` Russell King - ARM Linux
2015-05-15 12:45 ` Mason
2015-05-15 13:15 ` Russell King - ARM Linux
2015-05-14 14:48 ` Mason
2015-05-15 4:16 ` Viresh Kumar
2015-05-15 5:07 ` Viresh Kumar
2015-05-15 9:00 ` Russell King - ARM Linux
2015-05-15 9:21 ` Mason
2015-05-15 10:11 ` Mason
2015-05-12 15:23 ` Russell King - ARM Linux
2015-05-12 16:03 ` Mason
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