popnukem Posted May 18, 2018 Share Posted May 18, 2018 (edited) 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 May 19, 2018 by popnukem the UART also dies when a CPU is disabled, so i conclude the whole system is crashing. Link to comment Share on other sites More sharing options...
km1kze Posted May 22, 2018 Share Posted May 22, 2018 did you tried connecting to AV/HDMI? Link to comment Share on other sites More sharing options...
tkaiser Posted May 22, 2018 Share Posted May 22, 2018 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. 1 Link to comment Share on other sites More sharing options...
guidol Posted May 22, 2018 Share Posted May 22, 2018 6 hours ago, tkaiser said: to get a dual-core system. for low-power/thermal or underclocking-reasons? Link to comment Share on other sites More sharing options...
tkaiser Posted May 22, 2018 Share Posted May 22, 2018 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) Link to comment Share on other sites More sharing options...
popnukem Posted May 23, 2018 Author Share Posted May 23, 2018 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 Link to comment Share on other sites More sharing options...
Recommended Posts