"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. >Windows XP was launched in 2001, and the first dual core processors able >to execute Windows were AMD Opteron and IBM Pentium D, both launched >around April 2005 (and targeting the server market, not the home/desktop >market of Windows XP). >How could MS know in 2001 of a hardware issue that would happen four years >in the future? No, you're underestimating the problem. The issue occurs just as much in machines with multiple processor chips, which was supported clear back in the original NT 3.1, 1992. -- Tim Roberts, t...@probo.com Providenza & Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
