… | |
… | |
983 | In general you can register as many read and/or write event watchers per |
983 | In general you can register as many read and/or write event watchers per |
984 | fd as you want (as long as you don't confuse yourself). Setting all file |
984 | fd as you want (as long as you don't confuse yourself). Setting all file |
985 | descriptors to non-blocking mode is also usually a good idea (but not |
985 | descriptors to non-blocking mode is also usually a good idea (but not |
986 | required if you know what you are doing). |
986 | required if you know what you are doing). |
987 | |
987 | |
988 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
989 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
990 | descriptors correctly if you register interest in two or more fds pointing |
|
|
991 | to the same underlying file/socket/etc. description (that is, they share |
|
|
992 | the same underlying "file open"). |
|
|
993 | |
|
|
994 | If you must do this, then force the use of a known-to-be-good backend |
988 | If you must do this, then force the use of a known-to-be-good backend |
995 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
989 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
996 | C<EVBACKEND_POLL>). |
990 | C<EVBACKEND_POLL>). |
997 | |
991 | |
998 | Another thing you have to watch out for is that it is quite easy to |
992 | Another thing you have to watch out for is that it is quite easy to |
… | |
… | |
1033 | |
1027 | |
1034 | =head3 The special problem of dup'ed file descriptors |
1028 | =head3 The special problem of dup'ed file descriptors |
1035 | |
1029 | |
1036 | Some backends (e.g. epoll), cannot register events for file descriptors, |
1030 | Some backends (e.g. epoll), cannot register events for file descriptors, |
1037 | but only events for the underlying file descriptions. That means when you |
1031 | but only events for the underlying file descriptions. That means when you |
1038 | have C<dup ()>'ed file descriptors and register events for them, only one |
1032 | have C<dup ()>'ed file descriptors or weirder constellations, and register |
1039 | file descriptor might actually receive events. |
1033 | events for them, only one file descriptor might actually receive events. |
1040 | |
1034 | |
1041 | There is no workaround possible except not registering events |
1035 | There is no workaround possible except not registering events |
1042 | for potentially C<dup ()>'ed file descriptors, or to resort to |
1036 | for potentially C<dup ()>'ed file descriptors, or to resort to |
1043 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>. |
1037 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>. |
1044 | |
1038 | |
… | |
… | |
1073 | =item int events [read-only] |
1067 | =item int events [read-only] |
1074 | |
1068 | |
1075 | The events being watched. |
1069 | The events being watched. |
1076 | |
1070 | |
1077 | =back |
1071 | =back |
|
|
1072 | |
|
|
1073 | =head3 Examples |
1078 | |
1074 | |
1079 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
1075 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
1080 | readable, but only once. Since it is likely line-buffered, you could |
1076 | readable, but only once. Since it is likely line-buffered, you could |
1081 | attempt to read a whole line in the callback. |
1077 | attempt to read a whole line in the callback. |
1082 | |
1078 | |
… | |
… | |
1180 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1176 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1181 | which is also when any modifications are taken into account. |
1177 | which is also when any modifications are taken into account. |
1182 | |
1178 | |
1183 | =back |
1179 | =back |
1184 | |
1180 | |
|
|
1181 | =head3 Examples |
|
|
1182 | |
1185 | Example: Create a timer that fires after 60 seconds. |
1183 | Example: Create a timer that fires after 60 seconds. |
1186 | |
1184 | |
1187 | static void |
1185 | static void |
1188 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1186 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1189 | { |
1187 | { |
… | |
… | |
1346 | When active, contains the absolute time that the watcher is supposed to |
1344 | When active, contains the absolute time that the watcher is supposed to |
1347 | trigger next. |
1345 | trigger next. |
1348 | |
1346 | |
1349 | =back |
1347 | =back |
1350 | |
1348 | |
|
|
1349 | =head3 Examples |
|
|
1350 | |
1351 | Example: Call a callback every hour, or, more precisely, whenever the |
1351 | Example: Call a callback every hour, or, more precisely, whenever the |
1352 | system clock is divisible by 3600. The callback invocation times have |
1352 | system clock is divisible by 3600. The callback invocation times have |
1353 | potentially a lot of jittering, but good long-term stability. |
1353 | potentially a lot of jittering, but good long-term stability. |
1354 | |
1354 | |
1355 | static void |
1355 | static void |
… | |
… | |
1446 | |
1446 | |
1447 | The process exit/trace status caused by C<rpid> (see your systems |
1447 | The process exit/trace status caused by C<rpid> (see your systems |
1448 | C<waitpid> and C<sys/wait.h> documentation for details). |
1448 | C<waitpid> and C<sys/wait.h> documentation for details). |
1449 | |
1449 | |
1450 | =back |
1450 | =back |
|
|
1451 | |
|
|
1452 | =head3 Examples |
1451 | |
1453 | |
1452 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1454 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1453 | |
1455 | |
1454 | static void |
1456 | static void |
1455 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1457 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
… | |
… | |
1496 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1498 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1497 | to fall back to regular polling again even with inotify, but changes are |
1499 | to fall back to regular polling again even with inotify, but changes are |
1498 | usually detected immediately, and if the file exists there will be no |
1500 | usually detected immediately, and if the file exists there will be no |
1499 | polling. |
1501 | polling. |
1500 | |
1502 | |
|
|
1503 | =head3 Inotify |
|
|
1504 | |
|
|
1505 | When C<inotify (7)> support has been compiled into libev (generally only |
|
|
1506 | available on Linux) and present at runtime, it will be used to speed up |
|
|
1507 | change detection where possible. The inotify descriptor will be created lazily |
|
|
1508 | when the first C<ev_stat> watcher is being started. |
|
|
1509 | |
|
|
1510 | Inotify presense does not change the semantics of C<ev_stat> watchers |
|
|
1511 | except that changes might be detected earlier, and in some cases, to avoid |
|
|
1512 | making regular C<stat> calls. Even in the presense of inotify support |
|
|
1513 | there are many cases where libev has to resort to regular C<stat> polling. |
|
|
1514 | |
|
|
1515 | (There is no support for kqueue, as apparently it cannot be used to |
|
|
1516 | implement this functionality, due to the requirement of having a file |
|
|
1517 | descriptor open on the object at all times). |
|
|
1518 | |
|
|
1519 | =head3 The special problem of stat time resolution |
|
|
1520 | |
|
|
1521 | The C<stat ()> syscall only supports full-second resolution portably, and |
|
|
1522 | even on systems where the resolution is higher, many filesystems still |
|
|
1523 | only support whole seconds. |
|
|
1524 | |
|
|
1525 | That means that, if the time is the only thing that changes, you might |
|
|
1526 | miss updates: on the first update, C<ev_stat> detects a change and calls |
|
|
1527 | your callback, which does something. When there is another update within |
|
|
1528 | the same second, C<ev_stat> will be unable to detect it. |
|
|
1529 | |
|
|
1530 | The solution to this is to delay acting on a change for a second (or till |
|
|
1531 | the next second boundary), using a roughly one-second delay C<ev_timer> |
|
|
1532 | (C<ev_timer_set (w, 0., 1.01); ev_timer_again (loop, w)>). The C<.01> |
|
|
1533 | is added to work around small timing inconsistencies of some operating |
|
|
1534 | systems. |
|
|
1535 | |
1501 | =head3 Watcher-Specific Functions and Data Members |
1536 | =head3 Watcher-Specific Functions and Data Members |
1502 | |
1537 | |
1503 | =over 4 |
1538 | =over 4 |
1504 | |
1539 | |
1505 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1540 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
… | |
… | |
1542 | =item const char *path [read-only] |
1577 | =item const char *path [read-only] |
1543 | |
1578 | |
1544 | The filesystem path that is being watched. |
1579 | The filesystem path that is being watched. |
1545 | |
1580 | |
1546 | =back |
1581 | =back |
|
|
1582 | |
|
|
1583 | =head3 Examples |
1547 | |
1584 | |
1548 | Example: Watch C</etc/passwd> for attribute changes. |
1585 | Example: Watch C</etc/passwd> for attribute changes. |
1549 | |
1586 | |
1550 | static void |
1587 | static void |
1551 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1588 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
… | |
… | |
1564 | } |
1601 | } |
1565 | |
1602 | |
1566 | ... |
1603 | ... |
1567 | ev_stat passwd; |
1604 | ev_stat passwd; |
1568 | |
1605 | |
1569 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
1606 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1570 | ev_stat_start (loop, &passwd); |
1607 | ev_stat_start (loop, &passwd); |
|
|
1608 | |
|
|
1609 | Example: Like above, but additionally use a one-second delay so we do not |
|
|
1610 | miss updates (however, frequent updates will delay processing, too, so |
|
|
1611 | one might do the work both on C<ev_stat> callback invocation I<and> on |
|
|
1612 | C<ev_timer> callback invocation). |
|
|
1613 | |
|
|
1614 | static ev_stat passwd; |
|
|
1615 | static ev_timer timer; |
|
|
1616 | |
|
|
1617 | static void |
|
|
1618 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1619 | { |
|
|
1620 | ev_timer_stop (EV_A_ w); |
|
|
1621 | |
|
|
1622 | /* now it's one second after the most recent passwd change */ |
|
|
1623 | } |
|
|
1624 | |
|
|
1625 | static void |
|
|
1626 | stat_cb (EV_P_ ev_stat *w, int revents) |
|
|
1627 | { |
|
|
1628 | /* reset the one-second timer */ |
|
|
1629 | ev_timer_again (EV_A_ &timer); |
|
|
1630 | } |
|
|
1631 | |
|
|
1632 | ... |
|
|
1633 | ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
|
|
1634 | ev_stat_start (loop, &passwd); |
|
|
1635 | ev_timer_init (&timer, timer_cb, 0., 1.01); |
1571 | |
1636 | |
1572 | |
1637 | |
1573 | =head2 C<ev_idle> - when you've got nothing better to do... |
1638 | =head2 C<ev_idle> - when you've got nothing better to do... |
1574 | |
1639 | |
1575 | Idle watchers trigger events when no other events of the same or higher |
1640 | Idle watchers trigger events when no other events of the same or higher |
… | |
… | |
1600 | Initialises and configures the idle watcher - it has no parameters of any |
1665 | Initialises and configures the idle watcher - it has no parameters of any |
1601 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1666 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1602 | believe me. |
1667 | believe me. |
1603 | |
1668 | |
1604 | =back |
1669 | =back |
|
|
1670 | |
|
|
1671 | =head3 Examples |
1605 | |
1672 | |
1606 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1673 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1607 | callback, free it. Also, use no error checking, as usual. |
1674 | callback, free it. Also, use no error checking, as usual. |
1608 | |
1675 | |
1609 | static void |
1676 | static void |
… | |
… | |
1681 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1748 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1682 | macros, but using them is utterly, utterly and completely pointless. |
1749 | macros, but using them is utterly, utterly and completely pointless. |
1683 | |
1750 | |
1684 | =back |
1751 | =back |
1685 | |
1752 | |
|
|
1753 | =head3 Examples |
|
|
1754 | |
1686 | There are a number of principal ways to embed other event loops or modules |
1755 | There are a number of principal ways to embed other event loops or modules |
1687 | into libev. Here are some ideas on how to include libadns into libev |
1756 | into libev. Here are some ideas on how to include libadns into libev |
1688 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
1757 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
1689 | use for an actually working example. Another Perl module named C<EV::Glib> |
1758 | use for an actually working example. Another Perl module named C<EV::Glib> |
1690 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
1759 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
… | |
… | |
1858 | portable one. |
1927 | portable one. |
1859 | |
1928 | |
1860 | So when you want to use this feature you will always have to be prepared |
1929 | So when you want to use this feature you will always have to be prepared |
1861 | that you cannot get an embeddable loop. The recommended way to get around |
1930 | that you cannot get an embeddable loop. The recommended way to get around |
1862 | this is to have a separate variables for your embeddable loop, try to |
1931 | this is to have a separate variables for your embeddable loop, try to |
1863 | create it, and if that fails, use the normal loop for everything: |
1932 | create it, and if that fails, use the normal loop for everything. |
|
|
1933 | |
|
|
1934 | =head3 Watcher-Specific Functions and Data Members |
|
|
1935 | |
|
|
1936 | =over 4 |
|
|
1937 | |
|
|
1938 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
|
|
1939 | |
|
|
1940 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
|
|
1941 | |
|
|
1942 | Configures the watcher to embed the given loop, which must be |
|
|
1943 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
|
|
1944 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1945 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1946 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1947 | |
|
|
1948 | =item ev_embed_sweep (loop, ev_embed *) |
|
|
1949 | |
|
|
1950 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1951 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
|
|
1952 | apropriate way for embedded loops. |
|
|
1953 | |
|
|
1954 | =item struct ev_loop *other [read-only] |
|
|
1955 | |
|
|
1956 | The embedded event loop. |
|
|
1957 | |
|
|
1958 | =back |
|
|
1959 | |
|
|
1960 | =head3 Examples |
|
|
1961 | |
|
|
1962 | Example: Try to get an embeddable event loop and embed it into the default |
|
|
1963 | event loop. If that is not possible, use the default loop. The default |
|
|
1964 | loop is stored in C<loop_hi>, while the mebeddable loop is stored in |
|
|
1965 | C<loop_lo> (which is C<loop_hi> in the acse no embeddable loop can be |
|
|
1966 | used). |
1864 | |
1967 | |
1865 | struct ev_loop *loop_hi = ev_default_init (0); |
1968 | struct ev_loop *loop_hi = ev_default_init (0); |
1866 | struct ev_loop *loop_lo = 0; |
1969 | struct ev_loop *loop_lo = 0; |
1867 | struct ev_embed embed; |
1970 | struct ev_embed embed; |
1868 | |
1971 | |
… | |
… | |
1879 | ev_embed_start (loop_hi, &embed); |
1982 | ev_embed_start (loop_hi, &embed); |
1880 | } |
1983 | } |
1881 | else |
1984 | else |
1882 | loop_lo = loop_hi; |
1985 | loop_lo = loop_hi; |
1883 | |
1986 | |
1884 | =head3 Watcher-Specific Functions and Data Members |
1987 | Example: Check if kqueue is available but not recommended and create |
|
|
1988 | a kqueue backend for use with sockets (which usually work with any |
|
|
1989 | kqueue implementation). Store the kqueue/socket-only event loop in |
|
|
1990 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
1885 | |
1991 | |
1886 | =over 4 |
1992 | struct ev_loop *loop = ev_default_init (0); |
|
|
1993 | struct ev_loop *loop_socket = 0; |
|
|
1994 | struct ev_embed embed; |
|
|
1995 | |
|
|
1996 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
|
|
1997 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
|
|
1998 | { |
|
|
1999 | ev_embed_init (&embed, 0, loop_socket); |
|
|
2000 | ev_embed_start (loop, &embed); |
|
|
2001 | } |
1887 | |
2002 | |
1888 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
2003 | if (!loop_socket) |
|
|
2004 | loop_socket = loop; |
1889 | |
2005 | |
1890 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
2006 | // now use loop_socket for all sockets, and loop for everything else |
1891 | |
|
|
1892 | Configures the watcher to embed the given loop, which must be |
|
|
1893 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
|
|
1894 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1895 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1896 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1897 | |
|
|
1898 | =item ev_embed_sweep (loop, ev_embed *) |
|
|
1899 | |
|
|
1900 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1901 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
|
|
1902 | apropriate way for embedded loops. |
|
|
1903 | |
|
|
1904 | =item struct ev_loop *other [read-only] |
|
|
1905 | |
|
|
1906 | The embedded event loop. |
|
|
1907 | |
|
|
1908 | =back |
|
|
1909 | |
2007 | |
1910 | |
2008 | |
1911 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
2009 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
1912 | |
2010 | |
1913 | Fork watchers are called when a C<fork ()> was detected (usually because |
2011 | Fork watchers are called when a C<fork ()> was detected (usually because |
… | |
… | |
2438 | be detected at runtime. |
2536 | be detected at runtime. |
2439 | |
2537 | |
2440 | =item EV_H |
2538 | =item EV_H |
2441 | |
2539 | |
2442 | The name of the F<ev.h> header file used to include it. The default if |
2540 | The name of the F<ev.h> header file used to include it. The default if |
2443 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
2541 | undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to |
2444 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
2542 | virtually rename the F<ev.h> header file in case of conflicts. |
2445 | |
2543 | |
2446 | =item EV_CONFIG_H |
2544 | =item EV_CONFIG_H |
2447 | |
2545 | |
2448 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2546 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2449 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2547 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2450 | C<EV_H>, above. |
2548 | C<EV_H>, above. |
2451 | |
2549 | |
2452 | =item EV_EVENT_H |
2550 | =item EV_EVENT_H |
2453 | |
2551 | |
2454 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2552 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2455 | of how the F<event.h> header can be found. |
2553 | of how the F<event.h> header can be found, the dfeault is C<"event.h">. |
2456 | |
2554 | |
2457 | =item EV_PROTOTYPES |
2555 | =item EV_PROTOTYPES |
2458 | |
2556 | |
2459 | If defined to be C<0>, then F<ev.h> will not define any function |
2557 | If defined to be C<0>, then F<ev.h> will not define any function |
2460 | prototypes, but still define all the structs and other symbols. This is |
2558 | prototypes, but still define all the structs and other symbols. This is |
… | |
… | |
2632 | |
2730 | |
2633 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2731 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2634 | |
2732 | |
2635 | This means that, when you have a watcher that triggers in one hour and |
2733 | This means that, when you have a watcher that triggers in one hour and |
2636 | there are 100 watchers that would trigger before that then inserting will |
2734 | there are 100 watchers that would trigger before that then inserting will |
2637 | have to skip those 100 watchers. |
2735 | have to skip roughly seven (C<ld 100>) of these watchers. |
2638 | |
2736 | |
2639 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2737 | =item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers) |
2640 | |
2738 | |
2641 | That means that for changing a timer costs less than removing/adding them |
2739 | That means that changing a timer costs less than removing/adding them |
2642 | as only the relative motion in the event queue has to be paid for. |
2740 | as only the relative motion in the event queue has to be paid for. |
2643 | |
2741 | |
2644 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2742 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2645 | |
2743 | |
2646 | These just add the watcher into an array or at the head of a list. |
2744 | These just add the watcher into an array or at the head of a list. |
|
|
2745 | |
2647 | =item Stopping check/prepare/idle watchers: O(1) |
2746 | =item Stopping check/prepare/idle watchers: O(1) |
2648 | |
2747 | |
2649 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2748 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2650 | |
2749 | |
2651 | These watchers are stored in lists then need to be walked to find the |
2750 | These watchers are stored in lists then need to be walked to find the |
2652 | correct watcher to remove. The lists are usually short (you don't usually |
2751 | correct watcher to remove. The lists are usually short (you don't usually |
2653 | have many watchers waiting for the same fd or signal). |
2752 | have many watchers waiting for the same fd or signal). |
2654 | |
2753 | |
2655 | =item Finding the next timer per loop iteration: O(1) |
2754 | =item Finding the next timer in each loop iteration: O(1) |
|
|
2755 | |
|
|
2756 | By virtue of using a binary heap, the next timer is always found at the |
|
|
2757 | beginning of the storage array. |
2656 | |
2758 | |
2657 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2759 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2658 | |
2760 | |
2659 | A change means an I/O watcher gets started or stopped, which requires |
2761 | A change means an I/O watcher gets started or stopped, which requires |
2660 | libev to recalculate its status (and possibly tell the kernel). |
2762 | libev to recalculate its status (and possibly tell the kernel, depending |
|
|
2763 | on backend and wether C<ev_io_set> was used). |
2661 | |
2764 | |
2662 | =item Activating one watcher: O(1) |
2765 | =item Activating one watcher (putting it into the pending state): O(1) |
2663 | |
2766 | |
2664 | =item Priority handling: O(number_of_priorities) |
2767 | =item Priority handling: O(number_of_priorities) |
2665 | |
2768 | |
2666 | Priorities are implemented by allocating some space for each |
2769 | Priorities are implemented by allocating some space for each |
2667 | priority. When doing priority-based operations, libev usually has to |
2770 | priority. When doing priority-based operations, libev usually has to |
2668 | linearly search all the priorities. |
2771 | linearly search all the priorities, but starting/stopping and activating |
|
|
2772 | watchers becomes O(1) w.r.t. prioritiy handling. |
2669 | |
2773 | |
2670 | =back |
2774 | =back |
2671 | |
2775 | |
2672 | |
2776 | |
2673 | =head1 AUTHOR |
2777 | =head1 AUTHOR |