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