From: slash.tmp@free•fr (Mason)
To: linux-arm-kernel@lists•infradead.org
Subject: schedule_timeout sleeps too long after dividing CPU frequency
Date: Fri, 15 May 2015 12:11:18 +0200 [thread overview]
Message-ID: <5555C646.5030504@free.fr> (raw)
In-Reply-To: <20150515041632.GG6348@linux>
On 15/05/2015 06:16, Viresh Kumar wrote:
> On 14-05-15, 16:48, Mason wrote:
>
>> How do I run the TWD in one-shot mode?
>
> I haven't refreshed my memory for the earlier reply, but I have tried
> to go through the code again.
>
> The logic is this:
> - Oneshot mode is only useful if we are going to support NO_HZ mode.
> i.e. we can disable the clkevt device during CPU idle ..
> - For that to work, or in other words for the CPU to wake up from the
> idle state, we need a broadcast timer. Which will wake up the idle
> cpu and its clkevt device.
>
> You don't have this 'broadcast' timer in your case and so we aren't
> able to switch to oneshot mode.
>
> Even if you do that, you will be stuck in LOW resolution mode. And
> so you probably leave this timer as is and use a out-of-CPU-domain
> timer for this work, which can support high resolution mode.
For the record, my kernel config contains:
(There are some BROADCAST-related options enabled.)
#
# IRQ subsystem
#
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_GENERIC_IRQ_SHOW=y
CONFIG_HARDIRQS_SW_RESEND=y
CONFIG_IRQ_DOMAIN=y
# CONFIG_IRQ_DOMAIN_DEBUG is not set
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_KTIME_SCALAR=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BUILD=y
CONFIG_ARCH_HAS_TICK_BROADCAST=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
#
# Timers subsystem
#
CONFIG_TICK_ONESHOT=y
CONFIG_NO_HZ_COMMON=y
# CONFIG_HZ_PERIODIC is not set
CONFIG_NO_HZ_IDLE=y
# CONFIG_NO_HZ_FULL is not set
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
#
# CPU/Task time and stats accounting
#
CONFIG_TICK_CPU_ACCOUNTING=y
# CONFIG_VIRT_CPU_ACCOUNTING_GEN is not set
# CONFIG_IRQ_TIME_ACCOUNTING is not set
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_TASKSTATS is not set
Full config (and platform patch) provided in <555380F8.5050306@free•fr>
http://article.gmane.org/gmane.linux.power-management.general/60164
Regards.
next prev parent reply other threads:[~2015-05-15 10:11 UTC|newest]
Thread overview: 46+ 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
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
2015-05-15 13:58 ` Mason
2015-05-15 18:35 ` Mason
2015-05-18 11:24 ` Mason
2015-05-18 11:54 ` Russell King - ARM Linux
2015-05-20 16:21 ` Mason
2015-05-20 18:50 ` Arnd Bergmann
2015-05-20 19:34 ` Mason
2015-05-20 20:14 ` Russell King - ARM Linux
2015-05-20 20:41 ` Mason
2015-05-20 20:52 ` Arnd Bergmann
2015-05-20 21:56 ` Mason
2015-05-20 22:18 ` Arnd Bergmann
2015-05-21 12:35 ` Mason
2015-05-20 23:14 ` Russell King - ARM Linux
2015-05-21 9:56 ` Mason
2015-05-21 10:20 ` 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 [this message]
2015-05-12 15:23 ` Russell King - ARM Linux
2015-05-12 16:03 ` Mason
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