From: Peter Zijlstra <peterz@infradead.org>
To: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Viresh Kumar <viresh.kumar@linaro.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
shreyas@linux.vnet.ibm.com, akshay.adiga@linux.vnet.ibm.com,
linuxppc-dev@ozlabs.org, Steve Muckle <steve.muckle@linaro.org>
Subject: Re: [RFC PATCH] Increase in idle power with schedutil
Date: Sun, 22 May 2016 12:39:12 +0200 [thread overview]
Message-ID: <20160522103912.GN3193@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <201605201223.u4KCNWn9028105@mx0a-001b2d01.pphosted.com>
On Fri, May 20, 2016 at 05:53:41PM +0530, Shilpasri G Bhat wrote:
>
> Below are the comparisons by disabling watchdog.
> Both schedutil and ondemand have a similar ramp-down trend. And in both the
> cases I can see that frequency of the cpu is not reduced in deterministic
> fashion. In a observation window of 30 seconds after running a workload I can
> see that the frequency is not ramped down on some cpus in the system and are
> idling at max frequency.
So does it actually matter what the frequency is when you idle? Isn't
the whole thing clock gated anyway?
Because this seems to generate contradictory requirements, on the one
hand we want to stay idle as long as possible while on the other hand
you seem to want to clock down while idle, which requires not being
idle.
If it matters; should not your idle state muck explicitly set/restore
frequency?
next prev parent reply other threads:[~2016-05-22 10:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-18 12:53 [RFC PATCH] Increase in idle power with schedutil Shilpasri G Bhat
2016-05-18 12:53 ` [RFC PATCH] cpufreq: powernv: Add fast_switch callback Shilpasri G Bhat
2016-05-18 21:22 ` Rafael J. Wysocki
2016-05-18 21:11 ` [RFC PATCH] Increase in idle power with schedutil Rafael J. Wysocki
2016-05-19 11:40 ` Peter Zijlstra
2016-05-19 14:30 ` Rafael J. Wysocki
2016-05-20 12:23 ` Shilpasri G Bhat
[not found] ` <201605201223.u4KCNWn9028105@mx0a-001b2d01.pphosted.com>
2016-05-22 10:39 ` Peter Zijlstra [this message]
2016-05-22 20:42 ` Steve Muckle
2016-05-23 9:00 ` Lorenzo Pieralisi
2016-05-23 9:24 ` Peter Zijlstra
2016-05-23 9:24 ` Peter Zijlstra
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