From: Peter Zijlstra <peterz@infradead.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>,
"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: Thu, 19 May 2016 13:40:29 +0200 [thread overview]
Message-ID: <20160519114029.GW3193@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAJZ5v0jv+fD-ZKjLBepL9Fkn1JFROO3nGHX_3-=PuzGSAALB5g@mail.gmail.com>
On Wed, May 18, 2016 at 11:11:51PM +0200, Rafael J. Wysocki wrote:
> On Wed, May 18, 2016 at 2:53 PM, Shilpasri G Bhat
> <shilpa.bhat@linux.vnet.ibm.com> wrote:
> > This patch adds driver callback for fast_switch and below observations
> > on schedutil governor are done with this patch.
> >
> > In POWER8 there is a regression observed with schedutil compared to
> > ondemand. With schedutil the frequency is not ramping down and is
> > mostly stuck at max frequency during idle . This is because of the
> > watchdog timer, an RT task which is fired every 4 seconds which
> > results in requesting max frequency.
>
> Well, yes, that would be problematic.
>
Right; we need to come up with something for RT tasks; but what happens
if you disable the watchdog? This should be entirely doable and might
give a better comparison.
next prev parent reply other threads:[~2016-05-19 11:40 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 [this message]
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
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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