The CPU stats are shown as a percentage or values and for the configured refresh time.

The total CPU usage is displayed on the first line.


If enough horizontal space is available, extended CPU information are displayed.


A character is also displayed just after the CPU header and shows the trend value:

Trend Status
- CPU value is equal to the mean of the six latests refreshes
\ CPU value is lower than the mean of the six latests refreshes
/ CPU value is higher than the mean of the six latests refreshes

CPU stats description:

  • user: percent time spent in user space. User CPU time is the time spent on the processor running your program’s code (or code in libraries).
  • system: percent time spent in kernel space. System CPU time is the time spent running code in the Operating System kernel.
  • idle: percent of CPU used by any program. Every program or task that runs on a computer system occupies a certain amount of processing time on the CPU. If the CPU has completed all tasks it is idle.
  • nice (*nix): percent time occupied by user level processes with a positive nice value. The time the CPU has spent running users’ processes that have been niced.
  • irq (Linux, *BSD): percent time spent servicing/handling hardware/software interrupts. Time servicing interrupts (hardware + software).
  • iowait (Linux): percent time spent by the CPU waiting for I/O operations to complete.
  • steal (Linux): percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor.
  • ctx_sw: number of context switches (voluntary + involuntary) per second. A context switch is a procedure that a computer’s CPU (central processing unit) follows to change from one task (or process) to another while ensuring that the tasks do not conflict.
  • inter: number of interrupts per second.
  • sw_inter: number of software interrupts per second. Always set to 0 on Windows and SunOS.
  • syscal: number of system calls per second. Do not displayed on Linux (always 0).

To switch to per-CPU stats, just hit the 1 key:


By default, steal CPU time alerts aren’t logged. If you want that, just add to the configuration file:



CPU (user/system) Status
<50% OK


Limit values can be overwritten in the configuration file under the [cpu] and/or [percpu] sections.