[data from a 700MHz Athlon (stepping 2)]

PERFCTR INIT: vendor 2, family 6, model 1
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 76 cycles
PERFCTR INIT: rdtsc cost is 19.0 cycles (1293 total)
PERFCTR INIT: rdpmc cost is 11.1 cycles (791 total)
PERFCTR INIT: rdmsr (counter) cost is 52.8 cycles (3461 total)
PERFCTR INIT: rdmsr (evntsel) cost is 52.7 cycles (3451 total)
PERFCTR INIT: wrmsr (counter) cost is 82.2 cycles (5343 total)
PERFCTR INIT: wrmsr (evntsel) cost is 232.1 cycles (14934 total)
PERFCTR INIT: read %cr4 cost is 2.6 cycles (246 total)
PERFCTR INIT: write %cr4 cost is 63.0 cycles (4111 total)
perfctr: driver 2.0-pre4, cpu type AMD K7 at 704943 kHz
