1 | libev is modelled after libevent (http://monkey.org/~provos/libevent/), but aims |
1 | libev is modelled (very losely) after libevent |
|
|
2 | (http://monkey.org/~provos/libevent/), but aims to be faster and more |
2 | to be faster and more correct, and also more featureful. Examples: |
3 | correct, and also more featureful. Examples: |
3 | |
4 | |
|
|
5 | (comparisons relative to libevent-1.3e and libev-0.00) |
|
|
6 | |
4 | - multiple watchers can wait for the same event without deregistering others. |
7 | - multiple watchers can wait for the same event without deregistering others, |
|
|
8 | both for file descriptors as well as signals. |
5 | (registering two read events on fd 10 and unregistering one will not |
9 | (registering two read events on fd 10 and unregistering one will not |
6 | break the other) |
10 | break the other) |
7 | |
11 | |
8 | - fork() is supported and can be handled |
12 | - fork() is supported and can be handled |
9 | (there is no way to recover from a fork when libevent is active) |
13 | (there is no way to recover from a fork when libevent is active) |
10 | |
14 | |
11 | - timers are handled as a priority queue |
15 | - timers are handled as a priority queue (important operations are O(1)) |
12 | (libevent uses a less efficient red-black tree) |
16 | (libevent uses a much less efficient but more complex red-black tree) |
13 | |
17 | |
14 | - supports absolute (wallclock-based) timers in addition to relative ones, |
18 | - supports absolute (wallclock-based) timers in addition to relative ones, |
15 | i.e. can schedule timers to occur after n seconds, or at a specific time. |
19 | i.e. can schedule timers to occur after n seconds, or at a specific time. |
16 | |
20 | |
17 | - timers can be repeating (both absolute and relative ones) |
21 | - timers can be repeating (both absolute and relative ones) |
… | |
… | |
19 | - detects time jumps and adjusts timers |
23 | - detects time jumps and adjusts timers |
20 | (works for both forward and backward time jumps and also for absolute timers) |
24 | (works for both forward and backward time jumps and also for absolute timers) |
21 | |
25 | |
22 | - can correctly remove timers while executing callbacks |
26 | - can correctly remove timers while executing callbacks |
23 | (libevent doesn't handle this reliably and can crash) |
27 | (libevent doesn't handle this reliably and can crash) |
|
|
28 | |
|
|
29 | - race-free signal processing |
|
|
30 | (libevent may delay processing signals till after the next event) |
24 | |
31 | |
25 | - less calls to epoll_ctl |
32 | - less calls to epoll_ctl |
26 | (stopping and starting an io watcher between two loop iterations will now |
33 | (stopping and starting an io watcher between two loop iterations will now |
27 | result in spuriois epoll_ctl calls) |
34 | result in spuriois epoll_ctl calls) |
28 | |
35 | |
… | |
… | |
44 | (libevent combines them, but with libev you can combine them yourself |
51 | (libevent combines them, but with libev you can combine them yourself |
45 | by reusing the same callback and still save memory) |
52 | by reusing the same callback and still save memory) |
46 | |
53 | |
47 | - simpler design, backends are potentially much simpler |
54 | - simpler design, backends are potentially much simpler |
48 | (in libevent, backends have to deal with watchers, thus the problems) |
55 | (in libevent, backends have to deal with watchers, thus the problems) |
49 | (epoll backend in libevent: 366 lines, libev: 89 lines, and more features) |
56 | (epoll backend in libevent: 366 lines, libev: 90 lines, and more features) |
|
|
57 | |
|
|
58 | - libev handles EBADF gracefully by removing the offending fds. |
|
|
59 | |
|
|
60 | - doesn't rely on nonportable BSD header files. |
50 | |
61 | |
51 | whats missing? |
62 | whats missing? |
52 | |
63 | |
53 | - evdns, evhttp, bufferevent are missing, libev is only an even library at |
64 | - evdns, evhttp, bufferevent are missing, libev is only an even library at |
54 | the moment. |
65 | the moment. |
55 | |
66 | |
56 | - no priority support at the moment. |
67 | - no priority support at the moment |
57 | |
68 | |
58 | - kqueue, poll (libev currently implements epoll and select). |
69 | - kqueue, poll (libev currently implements epoll and select) |
59 | |
70 | |
|
|
71 | - windows support (whats windows?) |
|
|
72 | |