kcachegrind 20.04.1 Visualize profiles produces by Valgrind's Cachegrind tool
The data files generated by the Callgrind of Valgrind, an application profiler, can be loaded into KCachegrind for browsing the performance results. There is also a command-line tool to get ASCII reports from data files without the need to use KCachegrind.
The format of Callgrind output is documented. With conversion scripts, KCachegrind is able to visualize output of other profilers like OProfile, a system-wide profiler for Linux using statistical sampling with hardware performance counters. There also exist converters for profiling output of Python, PHP, and Perl.