[data from a 450MHz Pentium III (Katmai)]

PERFCTR INIT: vendor 0, family 6, model 7, stepping 3, clock 451026 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 89 cycles
PERFCTR INIT: rdtsc cost is 31.0 cycles (2078 total)
PERFCTR INIT: rdpmc cost is 34.3 cycles (2289 total)
PERFCTR INIT: rdmsr (counter) cost is 81.0 cycles (5279 total)
PERFCTR INIT: rdmsr (evntsel) cost is 68.9 cycles (4499 total)
PERFCTR INIT: wrmsr (counter) cost is 114.7 cycles (7433 total)
PERFCTR INIT: wrmsr (evntsel) cost is 105.3 cycles (6829 total)
PERFCTR INIT: read cr4 cost is 1.9 cycles (216 total)
PERFCTR INIT: write cr4 cost is 42.2 cycles (2794 total)
perfctr: driver 2.3.3, cpu type Intel Pentium III at 451026 kHz