bperf_trigger_reading
err = bperf_trigger_reading(evsel->bperf_leader_prog_fd, 0);
bperf_trigger_reading(evsel->bperf_leader_prog_fd, cpu.cpu);
int bperf_trigger_reading(int prog_fd, int cpu);
err = bperf_trigger_reading(prog_fd, 0);
bperf_trigger_reading(prog_fd, cpu.cpu);