rdclock
t1 = rdclock();
t0 = rdclock();
t = rdclock();
if ((rdclock() - t) > timeout) {
evsel->duration_time.start_time = rdclock();
evsel->duration_time.start_time = rdclock();
__u64 delta = rdclock() - evsel->duration_time.start_time;
delta_start += (rdclock() - evsel->duration_time.start_time);