Mastering Embedded Linux Programming - Second Edition

Profiling with perf

You can use perf to sample the state of a program using one of the event counters and accumulate samples over a period of time to create a profile. This is another example of statistical profiling. The default event counter is called cycles, which is a generic hardware counter that is mapped to a PMU register representing a count of cycles at the core clock frequency.

Creating a profile using perf is a two-stage process: the perf record command captures samples and writes them to a file named perf.data (by default), and then perf report analyzes the results. Both commands are run on the target. The samples being collected are filtered for the process and children of a command you specify. Here is an example profiling a ...