On Sun, Oct 31, 2010 at 3:59 PM, Oliver Kullmann <O.Kullmann@swansea.ac.uk> wrote:
I'm here experiencing an alarming problem (not just KDE or so, but the kernel): I have a laptop with a quadcore i5 processor, but the system doesn't want to use it! That's not good, since I rely on doing computational experiments with my laptop, and, of course, I purchased the quadcore laptop to do exactly that.
You are aware that a mobile Core i5 is actually a dual core processor with hyper threading? http://en.wikipedia.org/wiki/List_of_Intel_Core_i5_microprocessors Only 3 of the desktop Core i5's are true quad core, and they have hyperthreading disabled. The Linux kernel knows that the chip is actually a dual core with hyperthreading vs a true quad core, and will therefore schedule most tasks to work on the 2 actual cores, not the virtual cores. Win2k and XP had problems where they would use the virtual core and main core of the first chip of a dual proc system instead of the real 2 cores and performance would suffer. While the new Core ix series implementation of hyperthreading is better than what was on the P4s, it's still not a true additional core. Further, there are other issues: "Also, moving an application to two threads on a single SMT-enabled core will increase cache-thrashing by 42%, whereas it will decrease by 37% when moving to two cores." That's from this article: http://www.theinquirer.net/inquirer/news/1037948/arm-fan-hyperthreading Hyperthreading can be a nice boost, but a Core i7 with true quad core would be a better choice if you need 4 cores. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org