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From: Sudeep Holla <sudeep.holla@arm.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.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>,
	Sudeep Holla <sudeep.holla@arm.com>,
	"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 10:56:45 +0100	[thread overview]
Message-ID: <554B36DD.5080807@arm.com> (raw)
In-Reply-To: <20150507052600.20882.39542.stgit@preeti.in.ibm.com>

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.

Regards,
Sudeep

WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.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>,
	Sudeep Holla <sudeep.holla@arm.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 10:56:45 +0100	[thread overview]
Message-ID: <554B36DD.5080807@arm.com> (raw)
In-Reply-To: <20150507052600.20882.39542.stgit@preeti.in.ibm.com>

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.

Regards,
Sudeep

  reply	other threads:[~2015-05-07  9:56 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 [this message]
2015-05-07  9:56   ` Sudeep Holla
2015-05-07 17:49   ` Preeti U Murthy
2015-05-07 17:49     ` Preeti U Murthy

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