Linux Performance Profiling

[GROUNDING-GAP: perf/iostat/sar profiling — grounded on man pages + kernel perf docs; deepen with Systems Performance 2e and BPF Performance Tools (Brendan Gregg).]

Distro support

One-family-pair skill: the tools below behave identically on Debian/Ubuntu and the RHEL family (Fedora, RHEL, CentOS Stream, Rocky, Alma, Oracle). The /proc-backed tools (uptime, top, vmstat, free, ps) ship in procps (Debian) / procps-ng (RHEL) and are usually preinstalled. The sysstat tools (iostat, mpstat, pidstat, sar) come from the sysstat package on both families. perf is the only tool whose package name differs.