mpstat: CPU statistics at a glance
mpstat: CPU statistics at a glance
Pragmatic quick tour for beginners and intermediate users.
What mpstat does
- mpstat prints per CPU and aggregate statistics about CPU usage since boot and over intervals.
- It relies on the sysstat package and reads data from /proc/stat.
Quick start (examples first)
1) Display CPU statistics every 2 seconds
mpstat 2- This will print a fresh report every 2 seconds until you stop it with Ctrl+C.
2) Display 5 reports, one by one, at 2 second intervals
mpstat 2 5- You get a sequence of 5 reports, each 2 seconds apart.
3) Display 5 reports, one by one, from a given processor at 2 second intervals
mpstat -P 0 2 5- Replace 0 with the CPU number you care about. Other CPUs are not shown in the per CPU line.
How to read the output (quick guide)
- The first line is an overall summary since boot
- The following lines show per CPU usage metrics such as user, system, idle, iowait, etc.
- Look at the idle percentage to gauge how saturated your CPU is
Common pitfalls
- mpstat might not be installed by default; install the sysstat package on Debian/Ubuntu with sudo apt install sysstat or the equivalent on your distro
- The statistics are affected by system activity; for stable baselines, run a few steady-state reports before drawing conclusions
- If you specify a processor with -P, ensure the index exists on your system; otherwise you may get no per CPU line
Tips and tricks
- Use mpstat in scripts to log CPU usage over time; redirect output to a file for later analysis
- Combine with grep or awk to extract specific fields, e.g. mpstat 2 5 | tail -n +3 to skip the header lines
- For a quick health check, run with a short interval and watch the idle percentage
More resources
- Official page and man page: mpstat on manned.org
- If you see outdated cache info in your environment, consider updating tldr pages with tldr —update