[data from a 1.7 GHz Pentium-M]

PERFCTR INIT: vendor 0, family 6, model 9, stepping 5, clock 1694780 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 115 cycles
PERFCTR INIT: rdtsc cost is 48.6 cycles (3229 total)
PERFCTR INIT: rdpmc cost is 45.6 cycles (3038 total)
PERFCTR INIT: rdmsr (counter) cost is 95.5 cycles (6228 total)
PERFCTR INIT: rdmsr (evntsel) cost is 81.1 cycles (5311 total)
PERFCTR INIT: wrmsr (counter) cost is 143.8 cycles (9321 total)
PERFCTR INIT: wrmsr (evntsel) cost is 132.4 cycles (8592 total)
PERFCTR INIT: read cr4 cost is 2.8 cycles (298 total)
PERFCTR INIT: write cr4 cost is 49.7 cycles (3297 total)
PERFCTR INIT: write LVTPC cost is 8.6 cycles (667 total)
perfctr: driver 2.7.3, cpu type Intel P6 at 1694780 kHz