perf event
also: performance event, tracepoint, PMU event
A perf event is a countable hardware or software occurrence in the system that can be monitored and analyzed using the perf tool to profile application and kernel performance.
Perf events are the fundamental units of observation in Linux performance analysis. They represent occurrences such as CPU cycles, cache misses, branch instructions, page faults, or context switches that can be tracked and measured during program execution.
Events are categorized as either hardware events (generated by the CPU performance monitoring unit, like cycles and cache misses) or software events (generated by the kernel, like page faults and task migrations). You can list available events on your system with perf list.
For example, to count L1 data cache misses while running a program: perf stat -e L1-dcache-load-misses ./myprogram. You can sample events with perf record to build a detailed profile showing where time is spent, then analyze it with perf report.