The @stk_name@ supports DVFS (dynamic voltage and frequency scaling, by default the governor ''ondemand'' is set. Governors are power schemes for the CPU. Only one may be active at a time. ^ Governor ^ description ^ | performance | Run the CPU at the maximum frequency. | | powersave | Run the CPU at the minimum frequency. | | userspace | Run the CPU at user specified frequencies. | | ondemand | Scales the frequency dynamically according to current load. Jumps to the highest frequency and then possibly back off as the idle time increases. | | conservative | Scales the frequency dynamically according to current load. Scales the frequency more gradually than ondemand. | | schedutil | Scheduler-driven CPU frequency selection | You can change the actual governor with the following command: cpufreq-set -g (e.g. cpufreq-set -g performance) ==== Disable CPU Core temporarily ==== At runtime it is possible to disable multiple CPU cores via the Linux sysfs. On a system that has four CPU cores, the maximum of three cores can be disabled. To disable the a CPU core value ''0'' must be written to the CPU core specific file ''/sys/devices/system/cpu/cpu/online'' where is the number of the Core, the counting starts at zero. \\ e.g. disable CPU core 4: echo 0 > /sys/devices/system/cpu/cpu3/online To check which CPU core(s) are currently enabled the following command can be used: grep "processor" /proc/cpuinfo The CPU core can be enabled again by writing the value ''1'' to ''/sys/devices/system/cpu/cpu/online''.\\ \\ e.g. enable CPU core 4: echo 1 > /sys/devices/system/cpu/cpu3/online ==== Set ammount of CPU Cores permanently ==== It is possible to limit the maximium amount of cores with the the ''maxcpus='' parameter in the kernel command line. To add the new parameter a new U-boot variable ''addcpu'' has to be created. setenv addcpu maxcpus=${cpu_num} The amount of cores is set by the ''cpu_num'' variable, for example if cpu num is set to ''2'' only two cores will be started. setenv cpu_num 2