Re: Thermal notifications without setting thermal governor to userspace?

[Chris Down <chris@chrisdown.name>]

Daniel Lezcano writes:
>On 04/04/2022 19:17, Chris Down wrote:
>>Daniel Lezcano writes:
>>>Well on regular desktop, the thermal is managed under the hood by 
>>>the firmware/hardware, few sensors are exported AFAICT. I don't 
>>>think a thermal daemon would have a benefit on these platforms.
>>
>>Maybe we have different expectations? On my laptop, a Thinkpad T14s, 
>>things seem not too bad:
>
>That is not a desktop but a laptop, it is different :)

Oh, I see :-) I misread the distinction as embedded vs. consumer-facing.

>Can you give the content of:
>
>cat /sys/class/thermal/thermal_zone*/type
>cat /sys/class/thermal/thermal_zone*/trip_*type
>
>and
>
>cat /sys/class/thermal/cooling_device*/type

   % grep . /sys/class/thermal/thermal_zone*/type
   /sys/class/thermal/thermal_zone0/type:acpitz
   /sys/class/thermal/thermal_zone1/type:INT3400 Thermal
   /sys/class/thermal/thermal_zone2/type:SEN1
   /sys/class/thermal/thermal_zone3/type:SEN2
   /sys/class/thermal/thermal_zone4/type:TCPU
   /sys/class/thermal/thermal_zone5/type:iwlwifi_1
   /sys/class/thermal/thermal_zone6/type:x86_pkg_temp
   % grep . /sys/class/thermal/thermal_zone*/trip_*type
   /sys/class/thermal/thermal_zone0/trip_point_0_type:critical
   /sys/class/thermal/thermal_zone2/trip_point_0_type:critical
   /sys/class/thermal/thermal_zone2/trip_point_1_type:hot
   /sys/class/thermal/thermal_zone2/trip_point_2_type:passive
   /sys/class/thermal/thermal_zone3/trip_point_0_type:critical
   /sys/class/thermal/thermal_zone3/trip_point_1_type:hot
   /sys/class/thermal/thermal_zone3/trip_point_2_type:passive
   /sys/class/thermal/thermal_zone4/trip_point_0_type:critical
   /sys/class/thermal/thermal_zone4/trip_point_1_type:hot
   /sys/class/thermal/thermal_zone4/trip_point_2_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_0_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_1_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_2_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_3_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_4_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_5_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_6_type:passive
   /sys/class/thermal/thermal_zone5/trip_point_7_type:passive
   /sys/class/thermal/thermal_zone6/trip_point_0_type:passive
   /sys/class/thermal/thermal_zone6/trip_point_1_type:passive
   % grep . /sys/class/thermal/cooling_device*/type
   /sys/class/thermal/cooling_device0/type:Processor
   /sys/class/thermal/cooling_device1/type:Processor
   /sys/class/thermal/cooling_device2/type:Processor
   /sys/class/thermal/cooling_device3/type:Processor
   /sys/class/thermal/cooling_device4/type:Processor
   /sys/class/thermal/cooling_device5/type:Processor
   /sys/class/thermal/cooling_device6/type:Processor
   /sys/class/thermal/cooling_device7/type:Processor
   /sys/class/thermal/cooling_device8/type:intel_powerclamp
   /sys/class/thermal/cooling_device9/type:TCC Offset

>
>?
>
>
>>     % printf '%s\n' /sys/class/hwmon/hwmon*/temp*_input
>>     /sys/class/hwmon/hwmon1/temp1_input
>>     /sys/class/hwmon/hwmon2/temp1_input
>>     /sys/class/hwmon/hwmon2/temp2_input
>>     /sys/class/hwmon/hwmon2/temp3_input
>>     /sys/class/hwmon/hwmon4/temp1_input
>>     /sys/class/hwmon/hwmon4/temp2_input
>>     /sys/class/hwmon/hwmon4/temp3_input
>>     /sys/class/hwmon/hwmon4/temp4_input
>>     /sys/class/hwmon/hwmon4/temp5_input
>>     /sys/class/hwmon/hwmon4/temp6_input
>>     /sys/class/hwmon/hwmon4/temp7_input
>>     /sys/class/hwmon/hwmon4/temp8_input
>>     /sys/class/hwmon/hwmon6/temp1_input
>>     /sys/class/hwmon/hwmon8/temp1_input
>>     /sys/class/hwmon/hwmon8/temp2_input
>>     /sys/class/hwmon/hwmon8/temp3_input
>>     /sys/class/hwmon/hwmon8/temp4_input
>>     /sys/class/hwmon/hwmon8/temp5_input
>>
>>There are working temperature sensors out of the box for the CPU, 
>>wifi card, ACPI thermal zone, and extended sensors from 
>>thinkpad_acpi.
>>
>>In my case, I'd like to get notifications in userspace when certain 
>>temperatures are reached.
>>
>>So if I understood correctly, there's no way to dynamically 
>>configure temperature thresholds and get breach events even as root, 
>>even with the new netlink solution?
>
>There is a way but you need:
>
>1. A programmable trip point
>
>
>https://uefi.org/specs/ACPI/6.4/11_Thermal_Management/thermal-control.html#dynamically-changing-cooling-temperature-trip-points
>
>1.1 A passive trip point dedicated for userspace (no cooling device 
>associated)
>
>1.2 Writable kernel config option
>
>The trip point will be writable in sysfs
>
>2. Get trip point crossed
>
>Use the netlink
>
>But you don't need to monitor all these thermal zones, it is up to the 
>in-kernel thermal framework to deal with the trip point individually 
>and protect the system.
>
>The userspace should monitor what is considered as the 'case' sensor 
>or 'skin' sensor. The temperature on those sensor moves very slowly, 
>so monitoring them by getting the temperature every second should be 
>enough.

I see. I suspect this is probably too much to get from a distro kernel and 
myriad hardware, so I guess I'm consigned to using polling for the timebeing 
then.

Thanks a lot for chiming in with your knowledge :-)

Chris