perf_event__synthesize_cgroups
err = perf_event__synthesize_cgroups(tool, process_synthesized_event,
ret = perf_event__synthesize_cgroups(&top->tool, perf_event__process,
int perf_event__synthesize_cgroups(const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);