Date: Wed, 18 Nov 2015 16:04:40 +0000
From: Morten Rasmussen <morten.rasmussen@arm.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        John Stultz <john.stultz@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Len Brown <len.brown@intel.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>, Paul Turner <pjt@google.com>
Subject: Re: [PATCH 3/4] sched: introduce synchronized idle injection
Message-ID: <20151118160439.GE30184@e105550-lin.cambridge.arm.com>
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On Wed, Nov 18, 2015 at 07:11:31AM -0800, Jacob Pan wrote:
> On Wed, 18 Nov 2015 15:09:44 +0000
> Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> 
> > Okay. But it does mean that the defeault idle period is 5 ticks (50ms
> > @ HZ=100) and not 5 ms
> correct. my reason is to scale with various HZ values.

50ms seems quite long for embedded applications. OTOH, it has to be long
enough to enter a package idle state and stay there for a while. You
would surely notice it when it kicks in on an Android device.

Do you intend to use it only as a last option? One might want to keep
using inefficient frequencies (P-states) if those don't cause UI lag
then.
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