"Wouter Coppens" <wouter.coppens@dedigate.com> writes: > Hey, > > We would like to run 2.6 on a server, but I have a question about some > options: > > * Symmetric multi-processing support: > What happens if we enable this and run it on a uni-processor system? Nothing bad should happen. (If there are certain bugs in the kernel, they may not manifest in a UP-kernel, though.) > Will it run slower? It's unlikely, but you might be able to measure a difference. One thing that comes to mind is spinlocks. They get compiled away if you configure for a uniprocessor, but they take a few instructions on a SMP-enabled kernel. Test it and see. > * Preemptible Kernel: > This should be used on a desktop PC. Is it better to enable or disable > it on a system that is used only as a server or firewall? It's a fairly new feature, so I've been avoiding it so far. On the other hand, they added this feature for a reason, so you could benchmark both versions and see if there's enough of a performance improvement with preempt to justify using it. Incidentally, I did hear some kernel hacker mention that they wanted preempt to become not-turn-offable sometime in the future. -- --Ed L Cashin | PGP public key: ecashin@uga.edu | http://noserose.net/e/pgp/ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
