[Xenomai] xenomai 3.0.6 on RPi3 overheating when idle

[Steve Pavao]

Hello,

I’m having an overheating problem when running xenomai 3.0.6 on Raspberry Pi 3 with the recipes and defconfig from https://github.com/pficheux/meta-xenomai <https://github.com/pficheux/meta-xenomai> , but I’m using the altered kernel setting CONFIG_HZ=1000.

Under this configuration, the RPi3 overheats when idle.  I’d like to try to understand why.  Is there perhaps a defconfig settting I need to adjust, so that there will be not be so much heat-generating activity when the system is idle?  I did not observe anything useful with ps.

This is my first time successfully building and running xenomai on RPi3 32-bit using yocto recipes and a defconfig.  I built in rocko branch.  I notice there are many options in the defconfig which may affect operation. I do not 100% understand all these options, but I have started googling them to see if I can solve this issue.

I appreciate any ideas you may have.

Steve Pavao
Korg R&D

some of dmesg:

[    0.000000] Linux version 4.9.45-xeno (oe-user at oe-host) (gcc version 7.3.0 (GCC) ) #2 SMP Tue May 29 19:19:23 UTC 2018
[    0.000000] CPU: ARMv7 Processor [410fd034] revision 4 (ARMv7), cr=10c5383d

[    0.000000] arm_arch_timer: Architected cp15 timer(s) running at 19.20MHz (phys).
[    0.000000] I-pipe, 19.200 MHz clocksource, wrap in 960767920505705 ms
[    0.000000] clocksource: ipipe_tsc: mask: 0xffffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
[    0.000007] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 4398046511078ns
[    0.000025] Switching to timer-based delay loop, resolution 52ns
[    0.001464] Interrupt pipeline (release #2)

[    0.164653] [Xenomai] scheduling class idle registered.
[    0.164676] [Xenomai] scheduling class rt registered.
[    0.164820] I-pipe: head domain Xenomai registered.
[    0.166498] [Xenomai] Cobalt v3.0.6 (Stellar Parallax)