On Sun, 12 Jul 2009 07:34 +0200, "Joachim Schipper" <joac...@joachimschipper.nl> wrote: > On Sat, Jul 11, 2009 at 02:52:43PM -0500, Andres Salazar wrote: > > On Sat, Jul 11, 2009 at 1:54 AM, Jan-Erik Skata <jesk...@gmail.com> wrote > > > > > > Yes, you should use the SMP kernel on multicore CPUs aswell. I have > > > usually > > > just moved /bsd.mp onto /bsd and rebooted. > > > Otherwise only one CPU and/or core will be used. > > > > Ok, however since this is Symmetric MultiProcessing then I wouldnt benefit > > from running a mysql server because this is a single thread and it would > > still only use one core, right? > > > > Does OpenBSD support asymmetrical processing ? > > You have your terminology confused: the "symmetric" in SMP refers to the > identical treatment of identical processors, not to any way of mapping > threads to CPUs (CPU cores). See > http://en.wikipedia.org/wiki/Asymmetric_multiprocessing for details. > > OpenBSD's current threading model is n:1, which means that scheduling is > based on processes, not threads (i.e. only one thread of any given > process can be on the CPU at a given time). See > http://en.wikipedia.org/wiki/Thread_(computer_science)#Models. Some > people are working on changing this, but they have been at it for a > while and it is not production-ready yet. > > This does, indeed, mean that a multi-threaded process such as MySQL does > not benefit from having multiple cores in the box, except to the extent > that other work may be offloaded to other cores. > > I'll try to restrain myself from promoting PostgreSQL here... oops!
Not to mention the huge debate among programmers about the actual usefulness of multi-threading... but that's another story entirely.. check the archives and your favorite search engine.
