Created at: 2024-11-12
vmstat(8): Reports inofmration about processes, memory, pagin, block IO, traps, disks and cpu activity.
The first report produced gives averages since the last reboot. Additional reports give information on a sampling period of length delay. The process and memory reports are instantaneous in either case.
Although this command is called "virtual memory statistics", it prints system-wide CPU averages in the last columns, along with a count of runnable threads in the first column (Gregg).
vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- -------cpu-------
r b swpd free buff cache si so bi bo in cs us sy id wa st gu
1 0 0 6025620 56216 721664 0 0 365 28 902 3 1 1 98 0 0 0
0 0 0 6025620 56216 721700 0 0 0 0 662 2147 0 1 99 0 0 0
[...]
The relevant columns for CPU monitoring are:
r: Run-queue length. The total number of runnable threads.us: User-time percent.sy: System-time percent (kernel).id: Idle percent.wa: Wait I/O percent, which measures CPU idle when threads are blocked on
disk I/O.st: Stolen percent, which for virtualised envs shows CPU time spent
servicing other tenants.With the exception of r, all these values are systme-wide averages across all
CPUs.