2010-07-27 19:45:13 UTC
the setup is a dual 4 core Nehalem (E5540) with HyperThreading (HT) enabled
running under Windows 7 Enterprise x64.
We have made a simple program that creates threads and we put an affinity on
them. For example, we create 4 threads and set an affinity of 0xAA. In that
case, the 4 threads will not run in parallel. We will have 2 or 3 at most.
The only time we get the 4 threads running at the same time is if we set the
affinity to be all processors or if we force each thread to a single CPU.
Under Vista or with HT disabled, the behaviour is not seen.
Does anybody have an idea?