* Jason Baron <jbaron@xxxxxxxxxx> wrote: > > This has two main advantages: firstly it solves the > > O(N) (micro-)problem, but it also more evenly > > distributes events both between task-lists and within > > epoll groups as tasks as well. > > Its solving 2 issues - spurious wakeups, and more even > loading of threads. The event distribution is more even > between 'epoll groups' with this patch, however, if > multiple threads are blocking on a single 'epoll group', > this patch does not affect the the event distribution > there. [...] Regarding your last point, are you sure about that? If we have say 16 epoll threads registered, and if the list is static (no register/unregister activity), then the wakeup pattern is in strict order of the list: threads closer to the list head will be woken more frequently, in a wake-once fashion. So if threads do just quick work and go back to sleep quickly, then typically only the first 2-3 threads will get any runtime in practice - the wakeup iteration never gets 'deep' into the list. With the round-robin shuffling of the list, the threads get shuffled to the tail on wakeup, which distributes events evenly: all 16 epoll threads will accumulate an even distribution of runtime, statistically. Have I misunderstood this somehow? Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
