From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: peterz@infradead.org, tglx@linutronix.de,
rafael.j.wysocki@intel.com, daniel.lezcano@linaro.org,
rlippert@google.com, linux-pm@vger.kernel.org,
linus.walleij@linaro.org, linux-kernel@vger.kernel.org,
mingo@redhat.com, sudeep.holla@arm.com,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH V3] cpuidle: Handle tick_broadcast_enter() failure gracefully
Date: Sat, 09 May 2015 22:11:41 +0200 [thread overview]
Message-ID: <10239011.l6QLHlKIVm@vostro.rjw.lan> (raw)
In-Reply-To: <554D9FDC.6090608@linux.vnet.ibm.com>
On Saturday, May 09, 2015 11:19:16 AM Preeti U Murthy wrote:
> Hi Rafael,
>
> On 05/08/2015 07:48 PM, Rafael J. Wysocki wrote:
[cut]
> >>
> >> + /* Take note of the planned idle state. */
> >> + idle_set_state(smp_processor_id(), target_state);
> >
> > And I wouldn't do this either.
> >
> > The behavior here is pretty much as though the driver demoted the state chosen
> > by the governor and we don't call idle_set_state() again in those cases.
>
> Why is this wrong?
It is not "wrong", but incomplete, because demotions done by the cpuidle driver
should also be taken into account in the same way.
But I'm seeing that the recent patch of mine that made cpuidle_enter_state()
call default_idle_call() was a mistake, because it might confuse find_idlest_cpu()
significantly as to what state the CPU is in. I'll drop that one for now.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
next prev parent reply other threads:[~2015-05-09 19:46 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-08 7:35 Preeti U Murthy
2015-05-08 12:43 ` Sudeep Holla
2015-05-08 14:18 ` Rafael J. Wysocki
2015-05-08 21:51 ` Rafael J. Wysocki
2015-05-09 5:49 ` Preeti U Murthy
2015-05-09 18:46 ` Rafael J. Wysocki
2015-05-09 18:48 ` Rafael J. Wysocki
2015-05-09 20:11 ` Rafael J. Wysocki [this message]
2015-05-09 20:33 ` Rafael J. Wysocki
2015-05-09 23:15 ` [PATCH 0/3] cpuidle: updates related to tick_broadcast_enter() failures Rafael J. Wysocki
2015-05-09 23:18 ` [PATCH 1/3] sched / idle: Call idle_set_state() from cpuidle_enter_state() Rafael J. Wysocki
2015-05-09 23:18 ` [PATCH 2/3] sched / idle: Call default_idle_call() " Rafael J. Wysocki
2015-05-09 23:19 ` [PATCH 3/3] cpuidle: Select a different state on tick_broadcast_enter() failures Rafael J. Wysocki
2024-08-21 9:51 ` Dhruva Gole
2024-08-21 11:25 ` Rafael J. Wysocki
2015-05-11 3:48 ` [PATCH 0/3] cpuidle: updates related to " Preeti U Murthy
2015-05-11 5:21 ` Preeti U Murthy
2015-05-11 23:13 ` Rafael J. Wysocki
2015-05-11 15:13 ` Sudeep Holla
2015-05-11 23:14 ` Rafael J. Wysocki
2015-05-11 17:40 ` Daniel Lezcano
2015-05-11 23:31 ` Rafael J. Wysocki
2015-05-12 8:41 ` Daniel Lezcano
2015-05-12 13:23 ` Rafael J. Wysocki
2015-05-12 18:04 ` Daniel Lezcano
2015-05-13 22:59 ` Kevin Hilman
2015-05-14 0:16 ` Rafael J. Wysocki
2015-05-14 0:13 ` Kevin Hilman
2015-05-14 0:42 ` Rafael J. Wysocki
2015-05-14 0:31 ` Kevin Hilman
2015-05-14 3:59 ` Preeti U Murthy
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