From: Viresh Kumar <viresh.kumar@linaro.org>
To: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Linux PM <linux-pm@vger.kernel.org>,
Anson Huang <anson.huang@nxp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Juri Lelli <juri.lelli@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [BUG] schedutil governor produces regular max freq spikes because of lockup detector watchdog threads
Date: Wed, 10 Jan 2018 09:38:29 +0530 [thread overview]
Message-ID: <20180110040829.GB3335@vireshk-i7> (raw)
In-Reply-To: <1515508985.3310.8.camel@nxp.com>
On 09-01-18, 16:43, Leonard Crestez wrote:
> What I am saying is that as far as I can tell when cpufreq_update_util
> is called when the task has already executed and is been switched out.
Can you check if this patch makes it any better ?
https://marc.info/?l=linux-kernel&m=151204248901636&w=2
> My tests are not very elaborate but based on some ftracing it seems to
> me that the current behavior is for cpufreq spikes to always trail RT
> activity. Like this:
>
> <idle>-0 [002] 496.510138: sched_switch: swapper/2:0 [120] S ==> watchdog/2:20 [0]
> watchdog/2-20 [002] 496.510156: bprint: watchdog: IN watchdog(2)
> watchdog/2-20 [002] 496.510364: bprint: watchdog: OU watchdog(2)
> watchdog/2-20 [002] 496.510377: bprint: update_curr_rt: watchdog kick RT! cpu=2 comm=watchdog/2
Probabl update_curr_rt is getting called a bit after the task has
already run. The above patch moves the call to cpufreq_update_util()
to enqueue/dequeue paths and that should fix it.
--
viresh
next prev parent reply other threads:[~2018-01-10 4:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-05 20:37 [BUG] schedutil governor produces regular max freq spikes because of lockup detector watchdog threads Leonard Crestez
2018-01-05 22:18 ` Rafael J. Wysocki
2018-01-08 4:01 ` Viresh Kumar
2018-01-08 13:10 ` Rafael J. Wysocki
2018-01-08 13:20 ` Leonard Crestez
2018-01-08 15:14 ` Patrick Bellasi
2018-01-08 15:51 ` Leonard Crestez
2018-01-09 1:17 ` Rafael J. Wysocki
2018-01-09 14:43 ` Leonard Crestez
2018-01-09 15:16 ` Lucas Stach
2018-01-09 15:50 ` Rafael J. Wysocki
2018-01-10 10:54 ` Juri Lelli
2018-01-10 12:35 ` Rafael J. Wysocki
2018-01-10 14:21 ` Juri Lelli
2018-01-11 1:20 ` Rafael J. Wysocki
2018-01-10 4:08 ` Viresh Kumar [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-01-06 16:12 Doug Smythies
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