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popnukem

orange-pi zero plus (H5) crashes when disabling CPUs

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Hi Guys,

Sorry if this question has been tabled before, but i couldn't see it amongst the H5 topics.

I just bought two O-pi-zero+ and downloaded the two mainline releases from https://www.armbian.com/orange-pi-zero-plus: Armbian_5.38_Orangepizeroplus_Ubuntu_xenial_next_4.14.14.img  and Armbian_5.38_Orangepizeroplus_Debian_stretch_next_4.14.14.img

 

both seem to work just fine until i try to disable any of the CPUs, for example: "echo 0 >/sys/devices/system/cpu/cpu3/online".  i'm logged on using ssh and after this i get no response. this happens on both xenial and stretch, and on both boards.  i haven't tried connecting to the uart yet, but i just wondered if this is a known problem?

 

many thanks

Edited by popnukem
the UART also dies when a CPU is disabled, so i conclude the whole system is crashing.

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On 5/18/2018 at 5:19 AM, popnukem said:

until i try to disable any of the CPUs, for example: "echo 0 >/sys/devices/system/cpu/cpu3/online"

 

I experienced the same when playing with 4.14 on a NanoPi Fire 3. So maybe it's a problem of this kernel release? Anyway, I ended up adding

extraargs="maxcpus=2"

to /boot/armbianEnv.txt and rebooted to get a dual-core system.

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4 hours ago, guidol said:

for low-power/thermal or underclocking-reasons?

 

Nope. Just testing through zram efficiency: https://forum.armbian.com/topic/5565-zram-vs-swap/?do=findComment&comment=54725

 

 

Limiting count of CPU cores to reduce idle consumption is pretty much useless. My h3consumption approach allowing to limit count of active CPU cores is only about limiting 'worst case' consumption (something went wrong and there's a task utilizing all CPU cores -- in idle there's almost no difference whether there are 1, 2, 4 or 8 cores active. ARM guys are not stupid and implemented sorts of powermanagement ages ago)

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Armbian_5.38_Orangepizero_Ubuntu_xenial_next_4.14.14 on an o-pi-0 (H2+) works fine, i can enable and disable CPUs 1-3 at will using the "echo 0 >/sys/devices/system/cpu/cpu3/online" technique.

 

I am trying to minimise power consumption and heat output, but many of your techniques suggested for the H3 don't seem to work with the H5, so I've got a couple of orange-pi PC plus boards coming in the next couple of days. Hopefully the bigger board will also help with heat dissipation. 

 

thanks for your input

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