On Sat, Dec 17, 2005 at 04:43:05PM -0700, Matthew Wilcox wrote: > I have a better example of something we currently get wrong that I > haven't heard any RT person worry about yet. If two tasks are sleeping > on the same semaphore, the one to be woken up will be the first one to > wait for it, not the highest-priority task. > > Obviously, this was introduced by the wake-one semantics. But how to > fix it? Should we scan the entire queue looking for the best task to > wake? Should we try to maintain the wait list in priority order? Or > should we just not care? Should we document that we don't care? ;-)
-rt deals with this using priority sorted wait queue and direct ownership hand off to the woken thread. It's working fine for now, but things like wake-all and company should probably be explored for various uses. A strict general purpose and RT usage of the Linux kernel have different performance characteristic and mutex selection at compile time should address things precisely. bill - To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
