After updating to the L4T R28.2 release, I noticed that the TX1s I had were missing the
/sys/devices/system/cpu/cpu*/online and the
/sys/devices/system/cpu/cpuquiet/tegra_cpuquiet/enable sysfs devices.
Were they moved to a different location, or is there now a different mechanism to bringing up/down individual CPUs?
Also this means that the instructions on https://elinux.org/Jetson/TX1_Controlling_Performance are now failing. :(
Although I don’t see “tegra_cpuquiet” (R28.2), I do see all of:
One detail to consider is that cpu0 is always online, so it won’t have “cpu0/online”.
cpu3 do have the
online file. I always checked cpu0 only, it used to have the
online file back in R24.x days.
Anyway what about tegra_cpuquiet? We don’t need it anymore?
Yes, tegra_cpuquiet no longer exists on k4.4 TX1, TX2 or AGX Xavier.
The way to enable/disable cpu
To offline (hotunplug) core X
echo 0 > /sys/devices/system/cpu/cpuX/online
To online (hotplug) core X
echo 1 > /sys/devices/system/cpu/cpuX/online
To get list of online cores