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Comparing libev/ev.pod (file contents):
Revision 1.105 by root, Sun Dec 23 03:50:10 2007 UTC vs.
Revision 1.106 by root, Sun Dec 23 03:57:55 2007 UTC

… …
2632 2632
2633=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) 2633=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2634 2634
2635This means that, when you have a watcher that triggers in one hour and 2635This means that, when you have a watcher that triggers in one hour and
2636there are 100 watchers that would trigger before that then inserting will 2636there are 100 watchers that would trigger before that then inserting will
2637have to skip those 100 watchers. 2637have to skip roughly seven (C<ld 100>) of these watchers.
2638 2638
2639=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) 2639=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
2640 2640
2641That means that for changing a timer costs less than removing/adding them 2641That means that changing a timer costs less than removing/adding them
2642as only the relative motion in the event queue has to be paid for. 2642as only the relative motion in the event queue has to be paid for.
2643 2643
2644=item Starting io/check/prepare/idle/signal/child watchers: O(1) 2644=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2645 2645
2646These just add the watcher into an array or at the head of a list. 2646These just add the watcher into an array or at the head of a list.
2647
2647=item Stopping check/prepare/idle watchers: O(1) 2648=item Stopping check/prepare/idle watchers: O(1)
2648 2649
2649=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) 2650=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2650 2651
2651These watchers are stored in lists then need to be walked to find the 2652These watchers are stored in lists then need to be walked to find the
2652correct watcher to remove. The lists are usually short (you don't usually 2653correct watcher to remove. The lists are usually short (you don't usually
2653have many watchers waiting for the same fd or signal). 2654have many watchers waiting for the same fd or signal).
2654 2655
2655=item Finding the next timer per loop iteration: O(1) 2656=item Finding the next timer in each loop iteration: O(1)
2657
2658By virtue of using a binary heap, the next timer is always found at the
2659beginning of the storage array.
2656 2660
2657=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) 2661=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2658 2662
2659A change means an I/O watcher gets started or stopped, which requires 2663A change means an I/O watcher gets started or stopped, which requires
2660libev to recalculate its status (and possibly tell the kernel). 2664libev to recalculate its status (and possibly tell the kernel, depending
2665on backend and wether C<ev_io_set> was used).
2661 2666
2662=item Activating one watcher: O(1) 2667=item Activating one watcher (putting it into the pending state): O(1)
2663 2668
2664=item Priority handling: O(number_of_priorities) 2669=item Priority handling: O(number_of_priorities)
2665 2670
2666Priorities are implemented by allocating some space for each 2671Priorities are implemented by allocating some space for each
2667priority. When doing priority-based operations, libev usually has to 2672priority. When doing priority-based operations, libev usually has to
2668linearly search all the priorities. 2673linearly search all the priorities, but starting/stopping and activating
2674watchers becomes O(1) w.r.t. prioritiy handling.
2669 2675
2670=back 2676=back
2671 2677
2672 2678
2673=head1 AUTHOR 2679=head1 AUTHOR

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