Definition
cpu load average : The average number of process that is RUNNING and UNINTERRUPTABLE at the specific interval.
cpu usage (utilization) : The ratio or percentage about how much cpu time is used against the total cpu time (real time).
how to check the process of RUNNING and UNITERRUPTABLE
if Linux system, use “top” command
Tasks show the running tasks. Additionally, you can see each process state with “S”. D : UNINTERUPTABLE, R: RUNNING, S:SLEEP
How to get these metrics from Java Application
System Load Average
java.lang.package
OperatingSystemMXBean#getSystemLoadAverage
In Ubuntu, that is same as 1min systemloadaverage
Cpu Utilization
com.sun.management package
OperatingSystemMXBean#getCpuLoad
Cpu Utilization by JVM
com.sun.management package
OperatingSystemMXBean#getProcessCpuLoad
Indicate how much cpu is used for JVM process. 100% means that the cpu is used only JVM process at the period.
so,
getCpuLoad = getProcessCpuLoad (JVM process) + other processes
OpenTelemetry Java agent
The Java agent exports the following metrics by default.
