En Sat, 13 Feb 2010 17:29:45 -0300, Tim Roberts <t...@probo.com> escribió:
"Gabriel Genellina" <gagsl-...@yahoo.com.ar> 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
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