site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Relations, Developer Technical Support, Core OS/Hardware _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... At 19:32 -0500 11/12/06, Curtis Jones wrote: Anyway ... can anyone articulate the difference? This is just a matter of thread priority. The kernel thread that's used to implement bsd_timeout has a high, fixed priority. And, on a single CPU Mac OS X system, if a thread of priority X is available to run, threads of a priority less than X do not run at all. If you're doing CPU intensive stuff, you have to make sure than you run it in a low priority thread. User space threads, by default, are what we call "time shared". That is, as the thread consumes more and more CPU time, the kernel depresses its priority to give other threads a chance. Kernel threads, by default, are of fixed priority. This email sent to site_archiver@lists.apple.com