[data from a 1.1 GHz Athlon]

PERFCTR INIT: vendor 2, family 6, model 7, stepping 0, clock 1107644 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 157 cycles
PERFCTR INIT: rdtsc cost is 13.4 cycles (1015 total)
PERFCTR INIT: rdpmc cost is 15.0 cycles (1121 total)
PERFCTR INIT: rdmsr (counter) cost is 51.7 cycles (3472 total)
PERFCTR INIT: rdmsr (evntsel) cost is 52.8 cycles (3537 total)
PERFCTR INIT: wrmsr (counter) cost is 82.6 cycles (5447 total)
PERFCTR INIT: wrmsr (evntsel) cost is 231.6 cycles (14981 total)
PERFCTR INIT: read cr4 cost is 5.0 cycles (478 total)
PERFCTR INIT: write cr4 cost is 62.8 cycles (4180 total)
PERFCTR INIT: write LVTPC cost is 9.3 cycles (755 total)
PERFCTR INIT: sync_core cost is 76.9 cycles (5082 total)
perfctr: driver 2.7.4, cpu type AMD K7/K8 at 1107644 kHz