On 28/07/12 23:13, Mihai Carabas wrote: > Having an hyperthreading-aware scheduler shouldn't make any difference; > what could explain the above performance differences ? > > The heuristics I tested are about SMT (cache hotness heuristic - always > tries to schedule on the last CPU that had run on. If we can't schedule > on it and we are an cpu-bound process, we can wait for a tick to be > ellected by our home CPU. If we aren't pulled after that, we are > eligible and ready to be pulled on no matter what cpu). So, this > heuristic doesn't have anything to do with HT (hyper threading).
The newer heuristics Mihai implemented are not specific to SMT/HT, but affect any multi-core machine, pretty much. It takes topology in general into account; that is: sockets, cores on the socket, and if available, threads in a core (SMT/HT). In other words, his scheduling changes affect any SMP machine. HTH, Alex
