On Mon, 2006-03-13 at 07:37 -0500, Denis wrote: > Iain, > > So are you saying that a P4 is actually faster with HT disabled, or > simply that you don't have much to gain by using HT?
Well, I had read (in a previous HT thread on gentoo-user) that it did indeed degrade performance in many cases, but I've also seen reports that it increases performance in some areas greatly. Doing some more investigation I found this page: http://www-128.ibm.com/developerworks/linux/library/l-htl/ There is a lot of information out there - I googled for "hyperthreading performance linux" and got plenty of reading. So essentially I'm still undecided. > I've had a > dual-Xeon machine with 4 logical processors running Gentoo for a > couple years now, and I like being able to run 4 threads of > simulations at the same time. The threads, when started nearly > simultaneously, seem to finish the same jobs in nearly the same amount > of time... umm.. did I misunderstand something here? What exactly do you mean by threads? If I start some process 4 times on a single core, single cpu system, each one should finish in nearly the same amount of time, because process time gets equally allocated... Or did you mean 4 threads running together finish in the same amount of time as 1 thread running by itself? cya, -- Iain Buchanan <iain at netspace dot net dot au> You can't cheat the phone company. -- gentoo-user@gentoo.org mailing list
