From: Lianwei Wang <lianwei.wang@gmail.com>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>,
rjw@rjwysocki.net, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, kbuild-all@01.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH RESEND] smp: make wake up idle cpus more generic
Date: Sun, 3 Apr 2016 00:10:54 -0700 [thread overview]
Message-ID: <CAJFUiJhD1MVoO8aULspxn6cDeqPctsxtCoS-TNEjOyXf6B0YLg@mail.gmail.com> (raw)
In-Reply-To: <56FFC4D0.4090609@linaro.org>
On Sat, Apr 2, 2016 at 6:10 AM, Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
> On 04/02/2016 08:15 AM, Lianwei Wang wrote:
>>>
>>>
>>> * Lianwei Wang <lianwei.wang@gmail.com> wrote:
>>>
>>>> The wake_up_all_idle_cpus API always wake up all the online
>>>> cpus, but sometimes we only want to wake up a set of cpus.
>>>> Use a generic function to wake up a group of cpus that is
>>>> specified by the cpumask parameter. This generic API can
>>>> benefit to the cases that only need to wake up a set of
>>>> cpus.
>>>
>>>
>>> What is the new user of this new argument to the wake-up call?
>>>
>>> Thanks,
>>>
>>> Ingo
>>
>>
>> The ARM big.LITTLE arch is one of the users to use the new wake up
>> call. Two clusters in these SoCs and each cluster has 2 or more CPUs.
>> For some cases, we only need to wake up the cpus on one cluster, not
>> all the cpus. The other cluster can keep in idle state to save power.
>> Another use case is that for the threads/irqs that bind to some cpus,
>> we also want to wake up the cpus that the threads/irqs bind to, and
>> the other cpus can stay in idle state. I'm updating the pm_qos code to
>> support binding the request to a set of cpus, and the
>> cpuidle_latency_notify call can pass the cpumask parameter to the new
>> wake-up call.
>
>
> Hi Lianwei,
>
> a quick suggestion : cpuidle_driver->cpumask
>
> -- Daniel
>
>
> --
> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>
> Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
> <http://twitter.com/#!/linaroorg> Twitter |
> <http://www.linaro.org/linaro-blog/> Blog
>
Yes, Daniel. Send a cpumask to cpuidle_driver from pm_qos. Did you do
it already? Or are you planing to do it?
prev parent reply other threads:[~2016-04-03 7:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 5:50 [PATCH RESEND] smp: make wake up idle cpus more generic Lianwei Wang
2016-04-01 7:07 ` Ingo Molnar
2016-04-02 6:15 ` Lianwei Wang
2016-04-02 13:10 ` Daniel Lezcano
2016-04-03 7:10 ` Lianwei Wang [this message]
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