[data from a 2.0 GHz Pentium 4 (or possibly a Xeon)]

PERFCTR INIT: vendor 0, family 15, model 1, stepping 2, clock 1993687 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 496 cycles
PERFCTR INIT: rdtsc cost is 78.3 cycles (5512 total)
PERFCTR INIT: rdpmc cost is 145.0 cycles (9780 total)
PERFCTR INIT: rdmsr (counter) cost is 247.5 cycles (16340 total)
PERFCTR INIT: rdmsr (escr) cost is 162.9 cycles (10924 total)
PERFCTR INIT: wrmsr (counter) cost is 817.2 cycles (52800 total)
PERFCTR INIT: wrmsr (escr) cost is 877.0 cycles (56624 total)
PERFCTR INIT: read cr4 cost is 5.2 cycles (832 total)
PERFCTR INIT: write cr4 cost is 246.5 cycles (16276 total)
PERFCTR INIT: rdpmc (fast) cost is 59.3 cycles (4296 total)
PERFCTR INIT: rdmsr (cccr) cost is 163.5 cycles (10964 total)
PERFCTR INIT: wrmsr (cccr) cost is 839.6 cycles (54232 total)
PERFCTR INIT: write LVTPC cost is 43.5 cycles (3284 total)
PERFCTR INIT: sync_core cost is 254.7 cycles (16800 total)