On Fri, 4 May 2007, Davi Arnaut wrote: > Hi, > > If multiple threads are parked on epoll_wait (on a single epoll fd) and > events become available, epoll performs a wake up of all threads of the > poll wait list, causing a thundering herd of processes trying to grab > the eventpoll lock. > > This patch addresses this by using exclusive waiters (wake one). Once > the exclusive thread finishes transferring it's events, a new thread > is woken if there are more events available. > > Makes sense?
Theorically, make sense. I said theorically because all the use epoll_wait MT use cases I've heard of, use a single thread that does the epoll_wait, and then dispatch to worker threads. So thundering herd is not in the picture. OTOH, it does not hurt either. But, that code is completely changed with the new single-pass epoll delivery code that is in -mm. So, I'd either wait for that code to go in, or I (or you, if you like) can make a patch against -mm. - Davide - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
