Hi, On Sun, Jul 29, 2012 at 01:13:04AM +0300, Mihai Carabas wrote: > > > This machine is an old-school dual-Opteron 252 system and doesn't have > > any hyperthreading support at all. > > 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).
Not wanting to nitpick, but for me SMT = Simultaneous Multi Threading, of which Hyper Threading is a particular implementation. Nothing to do with cache-hotness heuristics per se :) -- Francois Tigeot
