C.5.10. Linux::Process Health

CPU Usage — The CPU usage rate for a given process in milliseconds per second. This metric reports the time column of ps output, which is the cumulative CPU time used by the process. This makes the metric independent of probe interval, allows sane thresholds to be set, and generates usable graphs (i.e. a sudden spike in CPU usage shows up as a spike in the graph).

Child Process Groups — The number of child processes spawned from the specified parent process. A child process inherits most of its attributes, such as open files, from its parent.

Threads — The number of running threads for a given process. A thread is the basic unit of CPU utilization, and consists of a program counter, a register set, and a stack space. A thread is also called a lightweight process.

Physical Memory Used — The amount of physical memory (or RAM) in kilobytes used by the specified process.

Virtual Memory Used — The amount of virtual memory in kilobytes used by the specified process, or the size of the process in real memory plus swap.