Subject: Re: [RFC PATCH 0/3] CFS idle injection
To: Peter Zijlstra <peterz@infradead.org>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>
References: <1446509428-5616-1-git-send-email-jacob.jun.pan@linux.intel.com>
 <20151104060654.GC8850@localhost.localdomain> <20151104085830.010e69f8@yairi>
 <20151105101218.GB3604@twins.programming.kicks-ass.net>
Cc: Eduardo Valentin <edubezval@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>, Paul Turner <pjt@google.com>,
        Len Brown <len.brown@intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Andi Kleen <andi.kleen@intel.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>
From: Dietmar Eggemann <dietmar.eggemann@arm.com>
Message-ID: <563CF1A9.8030700@arm.com>
Date: Fri, 6 Nov 2015 18:30:01 +0000
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On 05/11/15 10:12, Peter Zijlstra wrote:
> 
> People, trim your emails!
> 
> On Wed, Nov 04, 2015 at 08:58:30AM -0800, Jacob Pan wrote:
> 
>>> I also like #2 too. Specially now that it is not limited to a specific
>>> platform. One question though, could you still keep the cooling device
>>> support of it? In some systems, it might make sense to enable /
>>> disable idle injections based on temperature.
> 
>> One of the key difference between 1 and 2 is that #2 is open loop
>> control, since we don't have CPU c-states info baked into scheduler. 
> 
> _yet_, there's people working on that. The whole power aware scheduling
> stuff needs that.

Isn't the idle state information (rq->idle_state) already used in
find_idlest_cpu()?

What we use in energy aware scheduling is quite similar but since we're
interested in the index information of the c-state (to access the right
element of the idle_state vectors of the energy model, we added
rq->idle_state_idx.

[...]

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