From: Gabriel Genellina on
En Sat, 13 Feb 2010 17:29:45 -0300, Tim Roberts <timr(a)> escribi�:
> "Gabriel Genellina" <gagsl-py2(a)> wrote:
>> The original problem was with the RDTSC instruction on multicore CPUs;
>> different cores may yield different results because they're not
>> synchronized at all times.
> Not true. The synchronization issue has two causes: initial
> synchronization at boot time, and power management making microscopic
> adjustments to the clock rate. In Windows NT 4, Microsoft took extra
> pains
> to adjust the cycle counters on multiprocessor computers during boot so
> that the processors started out very close together. Once set, they
> naturally remained in lock step, until aggressive power management
> because
> more prevalent. In XP, they stopped trying to align at boot time.

Thanks for the detailed explanation!

Gabriel Genellina