[data from a dual quad-core 2.1 GHz Opteron 2352]

PERFCTR INIT: vendor 2, family 16, model 2, stepping 3, clock 2100001 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 877 cycles
PERFCTR INIT: rdtsc cost is 117.8 cycles (8420 total)
PERFCTR INIT: rdpmc cost is 9.1 cycles (1464 total)
PERFCTR INIT: rdmsr (counter) cost is 96.2 cycles (7034 total)
PERFCTR INIT: rdmsr (evntsel) cost is 110.9 cycles (7979 total)
PERFCTR INIT: wrmsr (counter) cost is 140.4 cycles (9864 total)
PERFCTR INIT: wrmsr (evntsel) cost is 447.3 cycles (29506 total)
PERFCTR INIT: read cr4 cost is 15.5 cycles (1875 total)
PERFCTR INIT: write cr4 cost is 130.4 cycles (9226 total)
PERFCTR INIT: write LVTPC cost is 57.3 cycles (4550 total)
PERFCTR INIT: sync_core cost is 240.0 cycles (16238 total)
perfctr: driver 2.6.35-pre1, cpu type AMD K7/K8/Fam10h at 2100001 kHz