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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 1.9 by root, Sun Jul 10 22:20:55 2005 UTC

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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);
8 32
9=head1 DESCRIPTION 33=head1 DESCRIPTION
10 34
11This module implements asynchronous I/O using whatever means your 35This module implements asynchronous I/O using whatever means your
12operating system supports. 36operating system supports.
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21remaining functionality would have to be implemented using threads anyway. 45remaining functionality would have to be implemented using threads anyway.
22 46
23Although the module will work with in the presence of other threads, it is 47Although the module will work with in the presence of other threads, it is
24currently not reentrant, so use appropriate locking yourself. 48currently not reentrant, so use appropriate locking yourself.
25 49
26=head2 API NOTES 50=cut
51
52package IO::AIO;
53
54use base 'Exporter';
55
56use Fcntl ();
57
58BEGIN {
59 $VERSION = 0.2;
60
61 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
62 aio_fsync aio_fdatasync aio_readahead);
63 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
64
65 require XSLoader;
66 XSLoader::load IO::AIO, $VERSION;
67}
68
69=head1 FUNCTIONS
70
71=head2 AIO FUNCTIONS
27 72
28All the C<aio_*> calls are more or less thin wrappers around the syscall 73All the C<aio_*> calls are more or less thin wrappers around the syscall
29with the same name (sans C<aio_>). The arguments are similar or identical, 74with the same name (sans C<aio_>). The arguments are similar or identical,
30and they all accept an additional C<$callback> argument which must be 75and they all accept an additional C<$callback> argument which must be
31a code reference. This code reference will get called with the syscall 76a code reference. This code reference will get called with the syscall
… …
39is that at the time the request is being executed, the current working 84is that at the time the request is being executed, the current working
40directory could have changed. Alternatively, you can make sure that you 85directory could have changed. Alternatively, you can make sure that you
41never change the current working directory. 86never change the current working directory.
42 87
43=over 4 88=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 89
126=item aio_open $pathname, $flags, $mode, $callback 90=item aio_open $pathname, $flags, $mode, $callback
127 91
128Asynchronously open or create a file and call the callback with a newly 92Asynchronously open or create a file and call the callback with a newly
129created filehandle for the file. 93created filehandle for the file.
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164 128
165Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at
166offset C<0> within the scalar: 130offset C<0> within the scalar:
167 131
168 aio_read $fh, 7, 15, $buffer, 0, sub { 132 aio_read $fh, 7, 15, $buffer, 0, sub {
169 $_[0] >= 0 or die "read error: $!"; 133 $_[0] > 0 or die "read error: $!";
170 print "read <$buffer>\n"; 134 print "read $_[0] bytes: <$buffer>\n";
171 }; 135 };
172 136
173=item aio_readahead $fh,$offset,$length, $callback 137=item aio_readahead $fh,$offset,$length, $callback
174 138
175Asynchronously reads the specified byte range into the page cache, using 139Asynchronously reads the specified byte range into the page cache, using
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220=item aio_fdatasync $fh, $callback 184=item aio_fdatasync $fh, $callback
221 185
222Asynchronously call fdatasync on the given filehandle and call the 186Asynchronously call fdatasync on the given filehandle and call the
223callback with the fdatasync result code. 187callback with the fdatasync result code.
224 188
189=back
190
191=head2 SUPPORT FUNCTIONS
192
193=over 4
194
195=item $fileno = IO::AIO::poll_fileno
196
197Return the I<request result pipe filehandle>. This filehandle must be
198polled for reading by some mechanism outside this module (e.g. Event
199or select, see below). If the pipe becomes readable you have to call
200C<poll_cb> to check the results.
201
202See C<poll_cb> for an example.
203
204=item IO::AIO::poll_cb
205
206Process all outstanding events on the result pipe. You have to call this
207regularly. Returns the number of events processed. Returns immediately
208when no events are outstanding.
209
210You can use Event to multiplex, e.g.:
211
212 Event->io (fd => IO::AIO::poll_fileno,
213 poll => 'r', async => 1,
214 cb => \&IO::AIO::poll_cb);
215
216=item IO::AIO::poll_wait
217
218Wait till the result filehandle becomes ready for reading (simply does a
219select on the filehandle. This is useful if you want to synchronously wait
220for some requests to finish).
221
222See C<nreqs> for an example.
223
224=item IO::AIO::nreqs
225
226Returns the number of requests currently outstanding.
227
228Example: wait till there are no outstanding requests anymore:
229
230 IO::AIO::poll_wait, IO::AIO::poll_cb
231 while IO::AIO::nreqs;
232
233=item IO::AIO::min_parallel $nthreads
234
235Set the minimum number of AIO threads to C<$nthreads>. The default is
236C<1>, which means a single asynchronous operation can be done at one time
237(the number of outstanding operations, however, is unlimited).
238
239It is recommended to keep the number of threads low, as some Linux
240kernel versions will scale negatively with the number of threads (higher
241parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
242threads should be fine.
243
244Under normal circumstances you don't need to call this function, as this
245module automatically starts some threads (the exact number might change,
246and is currently 4).
247
248=item IO::AIO::max_parallel $nthreads
249
250Sets the maximum number of AIO threads to C<$nthreads>. If more than
251the specified number of threads are currently running, kill them. This
252function blocks until the limit is reached.
253
254This module automatically runs C<max_parallel 0> at program end, to ensure
255that all threads are killed and that there are no outstanding requests.
256
257Under normal circumstances you don't need to call this function.
258
259=item $oldnreqs = IO::AIO::max_outstanding $nreqs
260
261Sets the maximum number of outstanding requests to C<$nreqs>. If you
262try to queue up more than this number of requests, the caller will block until
263some requests have been handled.
264
265The default is very large, so normally there is no practical limit. If you
266queue up many requests in a loop it it often improves speed if you set
267this to a relatively low number, such as C<100>.
268
269Under normal circumstances you don't need to call this function.
270
271=back
272
225=cut 273=cut
226 274
227# support function to convert a fd into a perl filehandle 275# support function to convert a fd into a perl filehandle
228sub _fd2fh { 276sub _fd2fh {
229 return undef if $_[0] < 0; 277 return undef if $_[0] < 0;
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242 max_parallel 0; 290 max_parallel 0;
243} 291}
244 292
2451; 2931;
246 294
247=back
248
249=head1 BUGS
250
251 - could be optimized to use more semaphores instead of filehandles.
252
253=head1 SEE ALSO 295=head1 SEE ALSO
254 296
255L<Coro>, L<Linux::AIO>. 297L<Coro>, L<Linux::AIO>.
256 298
257=head1 AUTHOR 299=head1 AUTHOR

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