pidstat

pidstat is a command-line monitoring utility that is part of the sysstat software package for Linux. It is designed to collect and report statistics about Linux processes and, optionally, their threads. pidstat can report on CPU usage, memory usage, input/output activity, and other per-process metrics, making it useful for performance analysis and troubleshooting.

The tool operates by taking samples over time. It can produce a one-shot report or run in intervals to show trends. Typical usage syntax is pidstat [options] [interval [count]], where interval controls the sampling period and count specifies how many samples to take. Users can filter the output to specific processes by PID or by command name, and may request different groups of statistics such as CPU, memory, or I/O. An option often used is to display per-thread data as well as per-process data.

Output from pidstat typically includes a row per process (and per thread when requested), with fields that cover CPU utilization (user and system time), memory metrics (virtual and resident size), and I/O statistics (reads and writes, throughput). It can also include context-switching and page fault information depending on the selected options. The format is plain text and designed for easy parsing in scripts and for quick manual inspection.

Pidstat relies on the /proc filesystem to gather data and is intended for Linux systems. It is widely used for performance monitoring, capacity planning, and identifying processes that dominate CPU time, memory, or I/O resources.