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| 6 | |
6 | |
| 7 | use Linux::AIO; |
7 | use Linux::AIO; |
| 8 | |
8 | |
| 9 | =head1 DESCRIPTION |
9 | =head1 DESCRIPTION |
| 10 | |
10 | |
| 11 | This module implements asynchroneous i/o using the means available to |
11 | This module implements asynchronous i/o using the means available to linux |
| 12 | linux - clone. It does not hook into the POSIX aio_* functions because |
12 | - clone. It does not hook into the POSIX aio_* functions because linux |
| 13 | linux does not yet support these in the kernel. Instead, a number of |
13 | does not yet support these in the kernel (and even if, it would only allow |
| 14 | threads are started that execute your read/writes and signal their |
14 | aio_read and write, not open and stat). |
| 15 | completion. |
15 | |
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16 | Instead, in this module a number of (non-posix) threads are started that |
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17 | execute your read/writes and signal their completion. You don't need |
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18 | thread support in your libc or perl, and the threads created by this |
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19 | module will not be visible to the pthreads library. |
| 16 | |
20 | |
| 17 | =over 4 |
21 | =over 4 |
| 18 | |
22 | |
| 19 | =cut |
23 | =cut |
| 20 | |
24 | |
| 21 | package Linux::AIO; |
25 | package Linux::AIO; |
| 22 | |
26 | |
| 23 | use base 'Exporter'; |
27 | use base 'Exporter'; |
| 24 | |
28 | |
| 25 | BEGIN { |
29 | BEGIN { |
| 26 | $VERSION = 0.2; |
30 | $VERSION = '1.0'; |
| 27 | |
31 | |
| 28 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat); |
32 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat); |
| 29 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs); |
33 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs); |
| 30 | |
34 | |
| 31 | require XSLoader; |
35 | require XSLoader; |
| 32 | XSLoader::load Linux::AIO, $VERSION; |
36 | XSLoader::load Linux::AIO, $VERSION; |
| 33 | } |
37 | } |
| 34 | |
38 | |
| 35 | =item Linux::AIO::min_parallel($nthreads) |
39 | =item Linux::AIO::min_parallel $nthreads |
| 36 | |
40 | |
| 37 | Set the minimum number of AIO threads to $nthreads. You I<have> to call |
41 | Set the minimum number of AIO threads to C<$nthreads>. You I<have> to call |
| 38 | this function with a positive number at leats once, otherwise no threads |
42 | this function with a positive number at least once, otherwise no threads |
| 39 | will be started and you aio-operations will seem to hang. |
43 | will be started and you aio-operations will seem to hang. |
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44 | |
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45 | It is recommended to keep the number of threads low, as many linux |
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46 | kernel versions will scale negatively with the number of threads (higher |
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47 | parallelity => MUCH higher latency). |
| 40 | |
48 | |
| 41 | =item $fileno = Linux::AIO::poll_fileno |
49 | =item $fileno = Linux::AIO::poll_fileno |
| 42 | |
50 | |
| 43 | Return the request result pipe filehandle. This filehandle must be polled |
51 | Return the I<request result pipe filehandle>. This filehandle must be |
| 44 | for reading. If the pipe becomes readable you have to call C<poll_cb>. |
52 | polled for reading by some mechanism outside this module (e.g. Event |
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53 | or select, see below). If the pipe becomes readable you have to call |
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54 | C<poll_cb> to check the results. |
| 45 | |
55 | |
| 46 | =item Linux::AIO::poll_cb |
56 | =item Linux::AIO::poll_cb |
| 47 | |
57 | |
| 48 | Process all outstanding events on the result pipe. You have to call this |
58 | Process all outstanding events on the result pipe. You have to call this |
| 49 | regularly. Returns the number of events processed. |
59 | regularly. Returns the number of events processed. Returns immediately |
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60 | when no events are outstanding. |
| 50 | |
61 | |
| 51 | You can use Event to multiplex, e.g.: |
62 | You can use Event to multiplex, e.g.: |
| 52 | |
63 | |
| 53 | Event->io(fd => Linux::AIO::poll_fileno, |
64 | Event->io (fd => Linux::AIO::poll_fileno, |
| 54 | poll => 'r', async => 1, |
65 | poll => 'r', async => 1, |
| 55 | cb => \&Linux::AIO::poll_cb ); |
66 | cb => \&Linux::AIO::poll_cb ); |
| 56 | |
67 | |
| 57 | |
68 | |
| 58 | =item Linux::AIO::nreqs |
69 | =item Linux::AIO::nreqs |
| 59 | |
70 | |
| 60 | Returns the number of requests currently outstanding. |
71 | Returns the number of requests currently outstanding. |
| 61 | |
72 | |
| 62 | =item aio_open($pathname, $flags, $mode, $callback) |
73 | =item aio_open $pathname, $flags, $mode, $callback |
| 63 | |
74 | |
| 64 | Asynchronously open or create a file and call the callback with the |
75 | Asynchronously open or create a file and call the callback with the |
| 65 | filedescriptor. |
76 | filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this |
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77 | might change in the future). |
| 66 | |
78 | |
| 67 | =item aio_close($fh, $callback) |
79 | =item aio_close $fh, $callback |
| 68 | |
80 | |
| 69 | Asynchronously close a file and call the callback with the result code. |
81 | Asynchronously close a file and call the callback with the result code. |
| 70 | |
82 | |
| 71 | =item aio_read($fh,$offset,$length, $data,$dataoffset,$callback) |
83 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
| 72 | |
84 | |
| 73 | =item aio_write($fh,$offset,$length, $data,$dataoffset,$callback) |
85 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
| 74 | |
86 | |
| 75 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
87 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
| 76 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
88 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
| 77 | callback without the actual number of bytes read (or undef on error). |
89 | callback without the actual number of bytes read (or C<undef> on error). |
| 78 | |
90 | |
| 79 | =item aio_stat($fh_or_path,$callback) |
91 | =item aio_stat $fh_or_path, $callback |
| 80 | |
92 | |
| 81 | =item aio_lstat($fh,$callback) |
93 | =item aio_lstat $fh, $callback |
| 82 | |
94 | |
| 83 | Works like perl's C<stat> or C<lstat> in void context, i.e. the callback |
95 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
| 84 | will be called after the stat and the results will be available using |
96 | be called after the stat and the results will be available using C<stat _> |
| 85 | C<stat _> or C<-s _> etc... |
97 | or C<-s _> etc... |
| 86 | |
98 | |
| 87 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
99 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
| 88 | error when stat'ing a large file, the results will be silently truncated |
100 | error when stat'ing a large file, the results will be silently truncated |
| 89 | unless perl itself is compiled with large file support. |
101 | unless perl itself is compiled with large file support. |
| 90 | |
102 | |
| … | |
… | |
| 98 | |
110 | |
| 99 | =back |
111 | =back |
| 100 | |
112 | |
| 101 | =head1 BUGS |
113 | =head1 BUGS |
| 102 | |
114 | |
| 103 | This module has not yet been extensively tested. Watch out! |
115 | This module has been extensively tested in a large and very busy webserver |
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116 | for many years now. |
| 104 | |
117 | |
| 105 | - perl-threads/fork interaction poorly tested. |
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| 106 | - aio_open gives a fd, but all other functions expect a filehandle. |
118 | - aio_open gives a fd, but all other functions expect a perl filehandle. |
| 107 | |
119 | |
| 108 | =head1 SEE ALSO |
120 | =head1 SEE ALSO |
| 109 | |
121 | |
| 110 | L<Coro>. |
122 | L<Coro>. |
| 111 | |
123 | |
