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

From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Pavel Machek <pavel@ucw.cz>,
	kernel list <linux-kernel@vger.kernel.org>,
	linux-acpi@vger.kernel.org, rui.zhang@intel.com,
	rjw@rjwysocki.net, viresh.kumar@linaro.org,
	linux-pm@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com,
	bp@alien8.de, hpa@zytor.com, x86@kernel.org
Subject: Re: 5.2-rc2: low framerate in flightgear, cpu not running at full speed, thermal related?
Date: Sun, 9 Jun 2019 15:55:16 +0200	[thread overview]
Message-ID: <22d57953-b032-6090-8efb-4e1d2add1b69@linaro.org> (raw)
In-Reply-To: <20190609121212.GA4520@amd>

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On 09/06/2019 14:12, Pavel Machek wrote:
> 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.

What is the cpufreq governor for v4.6 and v5.2-rc4?

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