On Mon, 07 Mar 2005 22:51:53 +0000, Jesse Scott <[EMAIL PROTECTED]> wrote:
> >Could hyperthreading be turned on for these machines? You will see better > >iteration times with hyperthreading turned off. > > Why is this true? You don't get something for nothing. In order to use hyperthreading there is an overhead cost to manage the multiple threads on the processor. If you are not using software that is optimized for hyperthreading then it is likely that it will run slower than if HT is disabled. I see the same thing in my parallel data compression code. On a dual-processor machine with HT turned on (so 2 physical and 2 virtual CPUs), the software runs more slowly. When I turn it off, I see quite a speed boost. Jeff. _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
