From: Arjan van de Ven <arjan@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org,
jacob.jun.pan@intel.com, fweisbec@gmail.com, frederic@kernel.org,
daniel.lezcano@linaro.org, amit.kucheria@linaro.org,
edubezval@gmail.com, viresh.kumar@linaro.org,
rui.zhang@intel.com
Subject: Re: [PATCH V2] idle/intel_powerclamp: Redesign idle injection to use bandwidth control mechanism
Date: Fri, 13 Feb 2015 06:03:38 -0800 [thread overview]
Message-ID: <54DE043A.9040605@linux.intel.com> (raw)
In-Reply-To: <20150213133158.GP2896@worktop.programming.kicks-ass.net>
> Also, exposing these and root_task_group is of course vile. Not to
> mention you change the user (cgroup) interface without mention.
>
> In any case, I cannot see how this could ever work. Bandwidth is shared
> across CPUs; nothing will even attempt to get CPUs to idle at the same
> time.
idle injection is only worth it if you can get package C states,
e.g. all cpus in the system are idle at the same time.
(and in powerclamp, the package C state %age is the target of the control
loop, since that's pretty much the amount of power reduced)
>
>
prev parent reply other threads:[~2015-02-13 14:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-09 4:49 [PATCH V2] idle/intel_powerclamp: Redesign idle injection to use bandwidth control mechanism Preeti U Murthy
2015-02-09 7:32 ` Steven Noonan
2015-02-09 11:51 ` Preeti U Murthy
2015-02-09 17:56 ` Steven Noonan
2015-02-09 18:14 ` Steven Noonan
2015-02-11 9:00 ` Preeti U Murthy
2015-02-13 13:31 ` Peter Zijlstra
2015-02-13 14:03 ` Arjan van de Ven [this message]
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