[data from a 1.3 GHz Athlon (XP 1500+)]

PERFCTR INIT: vendor 2, family 6, model 8, stepping 1, clock 1297680 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 159 cycles
PERFCTR INIT: rdtsc cost is 16.0 cycles (1189 total)
PERFCTR INIT: rdpmc cost is 16.4 cycles (1213 total)
PERFCTR INIT: rdmsr (counter) cost is 51.7 cycles (3474 total)
PERFCTR INIT: rdmsr (evntsel) cost is 53.3 cycles (3571 total)
PERFCTR INIT: wrmsr (counter) cost is 83.8 cycles (5523 total)
PERFCTR INIT: wrmsr (evntsel) cost is 231.7 cycles (14991 total)
PERFCTR INIT: read cr4 cost is 2.1 cycles (294 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 73.8 cycles (4883 total)
perfctr: driver 2.7.5, cpu type AMD K7/K8 at 1297680 kHz