[data from a 2.4 GHz Opteron 850]

PERFCTR INIT: vendor 2, family 15, model 5, stepping 10, clock 2405892 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 242 cycles
PERFCTR INIT: rdtsc cost is 13.0 cycles (1075 total)
PERFCTR INIT: rdpmc cost is 10.0 cycles (882 total)
PERFCTR INIT: rdmsr (counter) cost is 50.9 cycles (3505 total)
PERFCTR INIT: rdmsr (evntsel) cost is 56.8 cycles (3880 total)
PERFCTR INIT: wrmsr (counter) cost is 72.2 cycles (4863 total)
PERFCTR INIT: wrmsr (evntsel) cost is 328.8 cycles (21289 total)
PERFCTR INIT: read cr4 cost is 6.0 cycles (627 total)
PERFCTR INIT: write cr4 cost is 67.0 cycles (4535 total)
PERFCTR INIT: write LVTPC cost is 26.9 cycles (1967 total)
PERFCTR INIT: sync_core cost is 164.3 cycles (10761 total)