From: Preeti U Murthy <preeti@linux.vnet.ibm.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: "peterz@infradead.org" <peterz@infradead.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
"rlippert@google.com" <rlippert@google.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linus.walleij@linaro.org" <linus.walleij@linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] cpuidle: Handle tick_broadcast_enter() failure gracefully
Date: Thu, 07 May 2015 23:19:28 +0530 [thread overview]
Message-ID: <554BA5A8.3040009@linux.vnet.ibm.com> (raw)
In-Reply-To: <554B36DD.5080807@arm.com>
On 05/07/2015 03:26 PM, Sudeep Holla wrote:
> Hi Preeti,
>
> On 07/05/15 06:26, Preeti U Murthy wrote:
>> When a CPU has to enter an idle state where tick stops, it makes a call
>> to tick_broadcast_enter(). The call will fail if this CPU is the
>> broadcast CPU. Today, under such a circumstance, the arch cpuidle code
>> handles this CPU. This is not convincing because not only are we not
>> aware what the arch cpuidle code does, but we also do not account for
>> the idle state residency time and usage of such a CPU.
>>
>> This scenario can be handled better by simply asking the cpuidle
>> governor to choose an idle state where in ticks do not stop. To
>> accommodate this change move the setting of runqueue idle state from the
>> core to the cpuidle driver, else the rq->idle_state will be set wrong.
>>
>> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
>> ---
>> Based on linux-pm/bleeding-edge
>
> I am unable to apply this patch cleanly on linux-pm/bleeding-edge
> I think it conflicts with few patches that Rafael posted recently
> which are in the branch now.
Thanks so much for pointing out this! I have resent the patch as V2
after the rebase on the updated linux-pm/bleeding-edge branch
Regards
Preeti U Murthy
>
> Regards,
> Sudeep
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
WARNING: multiple messages have this Message-ID (diff)
From: Preeti U Murthy <preeti@linux.vnet.ibm.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: "rlippert@google.com" <rlippert@google.com>,
"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"linus.walleij@linaro.org" <linus.walleij@linaro.org>,
"rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] cpuidle: Handle tick_broadcast_enter() failure gracefully
Date: Thu, 07 May 2015 23:19:28 +0530 [thread overview]
Message-ID: <554BA5A8.3040009@linux.vnet.ibm.com> (raw)
In-Reply-To: <554B36DD.5080807@arm.com>
On 05/07/2015 03:26 PM, Sudeep Holla wrote:
> Hi Preeti,
>
> On 07/05/15 06:26, Preeti U Murthy wrote:
>> When a CPU has to enter an idle state where tick stops, it makes a call
>> to tick_broadcast_enter(). The call will fail if this CPU is the
>> broadcast CPU. Today, under such a circumstance, the arch cpuidle code
>> handles this CPU. This is not convincing because not only are we not
>> aware what the arch cpuidle code does, but we also do not account for
>> the idle state residency time and usage of such a CPU.
>>
>> This scenario can be handled better by simply asking the cpuidle
>> governor to choose an idle state where in ticks do not stop. To
>> accommodate this change move the setting of runqueue idle state from the
>> core to the cpuidle driver, else the rq->idle_state will be set wrong.
>>
>> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
>> ---
>> Based on linux-pm/bleeding-edge
>
> I am unable to apply this patch cleanly on linux-pm/bleeding-edge
> I think it conflicts with few patches that Rafael posted recently
> which are in the branch now.
Thanks so much for pointing out this! I have resent the patch as V2
after the rebase on the updated linux-pm/bleeding-edge branch
Regards
Preeti U Murthy
>
> Regards,
> Sudeep
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
next prev parent reply other threads:[~2015-05-07 17:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-07 5:26 [PATCH] cpuidle: Handle tick_broadcast_enter() failure gracefully Preeti U Murthy
2015-05-07 9:56 ` Sudeep Holla
2015-05-07 9:56 ` Sudeep Holla
2015-05-07 17:49 ` Preeti U Murthy [this message]
2015-05-07 17:49 ` Preeti U Murthy
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