diff options
| -rw-r--r-- | ev.pod | 30 |
1 files changed, 20 insertions, 10 deletions
@@ -606,21 +606,22 @@ Here are the gory details of what C<ev_loop> does: - Before the first iteration, call any pending watchers. * If EVFLAG_FORKCHECK was used, check for a fork. - - If a fork was detected, queue and call all fork watchers. + - If a fork was detected (by any means), queue and call all fork watchers. - Queue and call all prepare watchers. - - If we have been forked, recreate the kernel state. + - If we have been forked, detach and recreate the kernel state + as to not disturb the other process. - Update the kernel state with all outstanding changes. - - Update the "event loop time". + - Update the "event loop time" (ev_now ()). - Calculate for how long to sleep or block, if at all (active idle watchers, EVLOOP_NONBLOCK or not having any active watchers at all will result in not sleeping). - Sleep if the I/O and timer collect interval say so. - Block the process, waiting for any events. - Queue all outstanding I/O (fd) events. - - Update the "event loop time" and do time jump handling. + - Update the "event loop time" (ev_now ()), and do time jump adjustments. - Queue all outstanding timers. - Queue all outstanding periodics. - - If no events are pending now, queue all idle watchers. + - Unless any events are pending now, queue all idle watchers. - Queue all check watchers. - Call all queued watchers in reverse order (i.e. check watchers first). Signals and child watchers are implemented as I/O watchers, and will @@ -635,7 +636,7 @@ anymore. ... queue jobs here, make sure they register event watchers as long ... as they still have work to do (even an idle watcher will do..) ev_loop (my_loop, 0); - ... jobs done. yeah! + ... jobs done or somebody called unloop. yeah! =item ev_unloop (loop, how) @@ -681,12 +682,14 @@ Example: For some weird reason, unregister the above signal handler again. =item ev_set_timeout_collect_interval (loop, ev_tstamp interval) These advanced functions influence the time that libev will spend waiting -for events. Both are by default C<0>, meaning that libev will try to -invoke timer/periodic callbacks and I/O callbacks with minimum latency. +for events. Both time intervals are by default C<0>, meaning that libev +will try to invoke timer/periodic callbacks and I/O callbacks with minimum +latency. Setting these to a higher value (the C<interval> I<must> be >= C<0>) -allows libev to delay invocation of I/O and timer/periodic callbacks to -increase efficiency of loop iterations. +allows libev to delay invocation of I/O and timer/periodic callbacks +to increase efficiency of loop iterations (or to increase power-saving +opportunities). The background is that sometimes your program runs just fast enough to handle one (or very few) event(s) per loop iteration. While this makes @@ -712,6 +715,13 @@ interactive servers (of course not for games), likewise for timeouts. It usually doesn't make much sense to set it to a lower value than C<0.01>, as this approaches the timing granularity of most systems. +Setting the I<timeout collect interval> can improve the opportunity for +saving power, as the program will "bundle" timer callback invocations that +are "near" in time together, by delaying some, thus reducing the number of +times the process sleeps and wakes up again. Another useful technique to +reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure +they fire on, say, one-second boundaries only. + =item ev_loop_verify (loop) This function only does something when C<EV_VERIFY> support has been |