| … | |
… | |
| 358 | For few fds, this backend is a bit little slower than poll and select, |
358 | For few fds, this backend is a bit little slower than poll and select, |
| 359 | but it scales phenomenally better. While poll and select usually scale |
359 | but it scales phenomenally better. While poll and select usually scale |
| 360 | like O(total_fds) where n is the total number of fds (or the highest fd), |
360 | like O(total_fds) where n is the total number of fds (or the highest fd), |
| 361 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
361 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
| 362 | of shortcomings, such as silently dropping events in some hard-to-detect |
362 | of shortcomings, such as silently dropping events in some hard-to-detect |
| 363 | cases and rewiring a syscall per fd change, no fork support and bad |
363 | cases and requiring a syscall per fd change, no fork support and bad |
| 364 | support for dup. |
364 | support for dup. |
| 365 | |
365 | |
| 366 | While stopping, setting and starting an I/O watcher in the same iteration |
366 | While stopping, setting and starting an I/O watcher in the same iteration |
| 367 | will result in some caching, there is still a syscall per such incident |
367 | will result in some caching, there is still a syscall per such incident |
| 368 | (because the fd could point to a different file description now), so its |
368 | (because the fd could point to a different file description now), so its |
| … | |
… | |
| 2288 | |
2288 | |
| 2289 | This call incurs the overhead of a syscall only once per loop iteration, |
2289 | This call incurs the overhead of a syscall only once per loop iteration, |
| 2290 | so while the overhead might be noticable, it doesn't apply to repeated |
2290 | so while the overhead might be noticable, it doesn't apply to repeated |
| 2291 | calls to C<ev_async_send>. |
2291 | calls to C<ev_async_send>. |
| 2292 | |
2292 | |
|
|
2293 | =item bool = ev_async_pending (ev_async *) |
|
|
2294 | |
|
|
2295 | Returns a non-zero value when C<ev_async_send> has been called on the |
|
|
2296 | watcher but the event has not yet been processed (or even noted) by the |
|
|
2297 | event loop. |
|
|
2298 | |
|
|
2299 | C<ev_async_send> sets a flag in the watcher and wakes up the loop. When |
|
|
2300 | the loop iterates next and checks for the watcher to have become active, |
|
|
2301 | it will reset the flag again. C<ev_async_pending> can be used to very |
|
|
2302 | quickly check wether invoking the loop might be a good idea. |
|
|
2303 | |
|
|
2304 | Not that this does I<not> check wether the watcher itself is pending, only |
|
|
2305 | wether it has been requested to make this watcher pending. |
|
|
2306 | |
| 2293 | =back |
2307 | =back |
| 2294 | |
2308 | |
| 2295 | |
2309 | |
| 2296 | =head1 OTHER FUNCTIONS |
2310 | =head1 OTHER FUNCTIONS |
| 2297 | |
2311 | |
