$ Linux Command

Processes

mpstat

Report CPU usage statistics, per-processor if available.

cpuperformancemonitoringprocessorstats

Additional Notes

mpstat displays CPU usage statistics, including per-processor breakdown on multi-core systems. It is part of the sysstat package and reports values such as user time, system time, idle time, I/O wait, soft IRQ, and steal time (in virtualized environments).

It is useful for identifying CPU bottlenecks, unbalanced load across cores, excessive I/O wait, or CPU saturation. It provides both instantaneous snapshots and continuous monitoring at configurable intervals.

Syntax

mpstat [options] [interval [count]]

Parameters

  • interval: The time in seconds between reports.
  • count: The number of reports to generate. If not specified, reports continue indefinitely.

Common Options

  • -A: Show all CPU statistics (equivalent to -u -I ALL -P ALL).
  • -P cpu: Show statistics for a specific CPU or CPU range (e.g., -P 0, -P 0-3, -P ALL).
  • -u: Show CPU utilization statistics (default).
  • -I: Show interrupt statistics.
  • -I SUM: Show total interrupt count per processor.
  • -I CPU: Show interrupts per CPU.
  • -I ALL: Show all interrupt statistics.
  • -o JSON: Output in JSON format.
  • -o JSON-PRETTY: Output in pretty-printed JSON.

Examples

mpstat

Show a single report of overall CPU statistics.

mpstat -P ALL

Show per-processor statistics for all CPUs.

mpstat 2 5

Show CPU statistics every 2 seconds, 5 times.

mpstat -P 0 1

Monitor only CPU 0 every second.

mpstat -A

Show all available CPU statistics.

mpstat -I ALL

Show all interrupt statistics.

Output Fields

  • CPU: Processor number (or all for aggregate).
  • %usr: User-level CPU time percentage.
  • %nice: Time spent running nice'd user processes.
  • %sys: System/kernel CPU time.
  • %iowait: Time waiting for I/O to complete.
  • %irq: Time servicing hardware interrupts.
  • %soft: Time servicing software interrupts.
  • %steal: Time stolen by the hypervisor (in virtualized environments).
  • %guest: Time running a virtual processor.
  • %gnice: Time running a nice'd guest.
  • %idle: Idle time.

Practical Notes

  • High %iowait indicates disk or storage bottlenecks, not CPU saturation.
  • High %sys suggests driver, system call, or interrupt overhead.
  • %steal above 5% in virtual machines suggests the host is overcommitted.
  • mpstat is part of the sysstat package; install with apt install sysstat or equivalent.