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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.3 by root, Sun Jul 10 20:07:11 2005 UTC vs.
Revision 1.12 by root, Mon Jul 11 01:03:17 2005 UTC

… …
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub {
10 my ($fh) = @_;
11 ...
12 };
13
14 aio_unlink "/tmp/file", sub { };
15
16 aio_read $fh, 30000, 1024, $buffer, 0, sub {
17 $_[0] > 0 or die "read error: $!";
18 };
19
20 # Event
21 Event->io (fd => IO::AIO::poll_fileno,
22 poll => 'r',
23 cb => \&IO::AIO::poll_cb);
24
25 # Glib/Gtk2
26 add_watch Glib::IO IO::AIO::poll_fileno,
27 \&IO::AIO::poll_cb;
28
29 # Tk
30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
31 readable => \&IO::AIO::poll_cb);
32
33 # Danga::Socket
34 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
35 \&IO::AIO::poll_cb);
36
8 37
9=head1 DESCRIPTION 38=head1 DESCRIPTION
10 39
11This module implements asynchronous I/O using whatever means your 40This module implements asynchronous I/O using whatever means your
12operating system supports. 41operating system supports.
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21remaining functionality would have to be implemented using threads anyway. 50remaining functionality would have to be implemented using threads anyway.
22 51
23Although the module will work with in the presence of other threads, it is 52Although the module will work with in the presence of other threads, it is
24currently not reentrant, so use appropriate locking yourself. 53currently not reentrant, so use appropriate locking yourself.
25 54
26=head2 API NOTES 55=cut
56
57package IO::AIO;
58
59use base 'Exporter';
60
61use Fcntl ();
62
63BEGIN {
64 $VERSION = 0.3;
65
66 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
67 aio_fsync aio_fdatasync aio_readahead);
68 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
69
70 require XSLoader;
71 XSLoader::load IO::AIO, $VERSION;
72}
73
74=head1 FUNCTIONS
75
76=head2 AIO FUNCTIONS
27 77
28All the C<aio_*> calls are more or less thin wrappers around the syscall 78All the C<aio_*> calls are more or less thin wrappers around the syscall
29with the same name (sans C<aio_>). The arguments are similar or identical, 79with the same name (sans C<aio_>). The arguments are similar or identical,
30and they all accept an additional C<$callback> argument which must be 80and they all accept an additional C<$callback> argument which must be
31a code reference. This code reference will get called with the syscall 81a code reference. This code reference will get called with the syscall
… …
39is that at the time the request is being executed, the current working 89is that at the time the request is being executed, the current working
40directory could have changed. Alternatively, you can make sure that you 90directory could have changed. Alternatively, you can make sure that you
41never change the current working directory. 91never change the current working directory.
42 92
43=over 4 93=over 4
44
45=cut
46
47package IO::AIO;
48
49use base 'Exporter';
50
51use Fcntl ();
52
53BEGIN {
54 $VERSION = 0.2;
55
56 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
57 aio_fsync aio_fdatasync aio_readahead);
58 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs);
59
60 require XSLoader;
61 XSLoader::load IO::AIO, $VERSION;
62}
63
64=item IO::AIO::min_parallel $nthreads
65
66Set the minimum number of AIO threads to C<$nthreads>. The default is
67C<1>, which means a single asynchronous operation can be done at one time
68(the number of outstanding operations, however, is unlimited).
69
70It is recommended to keep the number of threads low, as some linux
71kernel versions will scale negatively with the number of threads (higher
72parallelity => MUCH higher latency).
73
74Under normal circumstances you don't need to call this function, as this
75module automatically starts a single async thread.
76
77=item IO::AIO::max_parallel $nthreads
78
79Sets the maximum number of AIO threads to C<$nthreads>. If more than
80the specified number of threads are currently running, kill them. This
81function blocks until the limit is reached.
82
83This module automatically runs C<max_parallel 0> at program end, to ensure
84that all threads are killed and that there are no outstanding requests.
85
86Under normal circumstances you don't need to call this function.
87
88=item $fileno = IO::AIO::poll_fileno
89
90Return the I<request result pipe filehandle>. This filehandle must be
91polled for reading by some mechanism outside this module (e.g. Event
92or select, see below). If the pipe becomes readable you have to call
93C<poll_cb> to check the results.
94
95See C<poll_cb> for an example.
96
97=item IO::AIO::poll_cb
98
99Process all outstanding events on the result pipe. You have to call this
100regularly. Returns the number of events processed. Returns immediately
101when no events are outstanding.
102
103You can use Event to multiplex, e.g.:
104
105 Event->io (fd => IO::AIO::poll_fileno,
106 poll => 'r', async => 1,
107 cb => \&IO::AIO::poll_cb);
108
109=item IO::AIO::poll_wait
110
111Wait till the result filehandle becomes ready for reading (simply does a
112select on the filehandle. This is useful if you want to synchronously wait
113for some requests to finish).
114
115See C<nreqs> for an example.
116
117=item IO::AIO::nreqs
118
119Returns the number of requests currently outstanding.
120
121Example: wait till there are no outstanding requests anymore:
122
123 IO::AIO::poll_wait, IO::AIO::poll_cb
124 while IO::AIO::nreqs;
125 94
126=item aio_open $pathname, $flags, $mode, $callback 95=item aio_open $pathname, $flags, $mode, $callback
127 96
128Asynchronously open or create a file and call the callback with a newly 97Asynchronously open or create a file and call the callback with a newly
129created filehandle for the file. 98created filehandle for the file.
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164 133
165Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 134Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at
166offset C<0> within the scalar: 135offset C<0> within the scalar:
167 136
168 aio_read $fh, 7, 15, $buffer, 0, sub { 137 aio_read $fh, 7, 15, $buffer, 0, sub {
169 $_[0] >= 0 or die "read error: $!"; 138 $_[0] > 0 or die "read error: $!";
170 print "read <$buffer>\n"; 139 print "read $_[0] bytes: <$buffer>\n";
171 }; 140 };
172 141
173=item aio_readahead $fh,$offset,$length, $callback 142=item aio_readahead $fh,$offset,$length, $callback
174 143
175Asynchronously reads the specified byte range into the page cache, using 144Asynchronously reads the specified byte range into the page cache, using
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220=item aio_fdatasync $fh, $callback 189=item aio_fdatasync $fh, $callback
221 190
222Asynchronously call fdatasync on the given filehandle and call the 191Asynchronously call fdatasync on the given filehandle and call the
223callback with the fdatasync result code. 192callback with the fdatasync result code.
224 193
194=back
195
196=head2 SUPPORT FUNCTIONS
197
198=over 4
199
200=item $fileno = IO::AIO::poll_fileno
201
202Return the I<request result pipe filehandle>. This filehandle must be
203polled for reading by some mechanism outside this module (e.g. Event
204or select, see below). If the pipe becomes readable you have to call
205C<poll_cb> to check the results.
206
207See C<poll_cb> for an example.
208
209=item IO::AIO::poll_cb
210
211Process all outstanding events on the result pipe. You have to call this
212regularly. Returns the number of events processed. Returns immediately
213when no events are outstanding.
214
215You can use Event to multiplex, e.g.:
216
217 Event->io (fd => IO::AIO::poll_fileno,
218 poll => 'r', async => 1,
219 cb => \&IO::AIO::poll_cb);
220
221=item IO::AIO::poll_wait
222
223Wait till the result filehandle becomes ready for reading (simply does a
224select on the filehandle. This is useful if you want to synchronously wait
225for some requests to finish).
226
227See C<nreqs> for an example.
228
229=item IO::AIO::nreqs
230
231Returns the number of requests currently outstanding.
232
233Example: wait till there are no outstanding requests anymore:
234
235 IO::AIO::poll_wait, IO::AIO::poll_cb
236 while IO::AIO::nreqs;
237
238=item IO::AIO::flush
239
240Wait till all outstanding AIO requests have been handled.
241
242=item IO::AIO::min_parallel $nthreads
243
244Set the minimum number of AIO threads to C<$nthreads>. The default is
245C<1>, which means a single asynchronous operation can be done at one time
246(the number of outstanding operations, however, is unlimited).
247
248It is recommended to keep the number of threads low, as some Linux
249kernel versions will scale negatively with the number of threads (higher
250parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
251threads should be fine.
252
253Under normal circumstances you don't need to call this function, as this
254module automatically starts some threads (the exact number might change,
255and is currently 4).
256
257=item IO::AIO::max_parallel $nthreads
258
259Sets the maximum number of AIO threads to C<$nthreads>. If more than
260the specified number of threads are currently running, kill them. This
261function blocks until the limit is reached.
262
263This module automatically runs C<max_parallel 0> at program end, to ensure
264that all threads are killed and that there are no outstanding requests.
265
266Under normal circumstances you don't need to call this function.
267
268=item $oldnreqs = IO::AIO::max_outstanding $nreqs
269
270Sets the maximum number of outstanding requests to C<$nreqs>. If you
271try to queue up more than this number of requests, the caller will block until
272some requests have been handled.
273
274The default is very large, so normally there is no practical limit. If you
275queue up many requests in a loop it it often improves speed if you set
276this to a relatively low number, such as C<100>.
277
278Under normal circumstances you don't need to call this function.
279
280=back
281
225=cut 282=cut
226 283
227# support function to convert a fd into a perl filehandle 284# support function to convert a fd into a perl filehandle
228sub _fd2fh { 285sub _fd2fh {
229 return undef if $_[0] < 0; 286 return undef if $_[0] < 0;
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242 max_parallel 0; 299 max_parallel 0;
243} 300}
244 301
2451; 3021;
246 303
247=back
248
249=head1 BUGS
250
251 - could be optimized to use more semaphores instead of filehandles.
252
253=head1 SEE ALSO 304=head1 SEE ALSO
254 305
255L<Coro>, L<Linux::AIO>. 306L<Coro>, L<Linux::AIO>.
256 307
257=head1 AUTHOR 308=head1 AUTHOR

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