linux-kernel - Re: 5.2-rc2: low framerate in flightgear, cpu not running at full speed, thermal related?

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Message-ID: <20190609121212.GA4520@amd>
Date:   Sun, 9 Jun 2019 14:12:12 +0200
From:   Pavel Machek <pavel@....cz>
To:     kernel list <linux-kernel@...r.kernel.org>,
        linux-acpi@...r.kernel.org, rui.zhang@...el.com, rjw@...ysocki.net,
        viresh.kumar@...aro.org, linux-pm@...r.kernel.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        x86@...nel.org
Subject: Re: 5.2-rc2: low framerate in flightgear, cpu not running at full
 speed, thermal related?

Hi!

> > When I start flightgear, I get framerates around 20 fps and cpu at
> > 3GHz:
> > 
> > pavel@duo:~/bt$ cat /proc/cpuinfo  | grep MHz
> > cpu MHz		    : 3027.471
> > cpu MHz		      : 2981.863
> > cpu MHz		      	: 2958.352
> > cpu MHz			  : 2864.001
> > pavel@duo:~/bt$
> > 
> > (Ok, fgfs is really only running at single core, so why do both cores
> > run at 3GHz?)
> > 
> > But temperatures get quite high:
> > 
> > pavel@duo:~/bt$ sensors
> > thinkpad-isa-0000
> > Adapter: ISA adapter
> > fan1:        4485 RPM
> > 
> > coretemp-isa-0000
> > Adapter: ISA adapter
> > Package id 0:  +98.0°C  (high = +86.0°C, crit = +100.0°C)
> > Core 0:        +98.0°C  (high = +86.0°C, crit = +100.0°C)
> > Core 1:        +91.0°C  (high = +86.0°C, crit = +100.0°C)
> > 
> > And soon cpu goes to 1.5GHz range, with framerates going down to
> > 12fps. That's a bit low.
> > 
> > Room temperature is 26Celsius.
> > 
> > The CPU is Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz . I guess it means
> > it should be able to sustain both cores running at 2.5GHz?
> > 
> > Any ideas? Were there any recent changes in that area?
> 
> I tried kernel compile. It keeps both cores at 3GHz, temperature goes
> up over 95C, and then cpus start going down to 2.3GHz... and then down
> to 2GHz... and down to 1.9GHz.
> 
> watch bash -c 'sensors;  cat /proc/cpuinfo | grep MHz'

Situation is very different with v4.6 distro based kernel.

CPU MHz is only getting values round to 100MHz. It does not go above
2.5GHz, but it does not go below 2.5GHz under the load, either.

ACPI adapter appears in sensors output.

Now I tried going to 5.2-rc4. It behaves the same as 5.2-rc2. Goes up
to 3GHz briefly but then down to 2.0GHz and below under load.

Ideas welcome.

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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