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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.4 by root, Sun Jul 10 20:57:00 2005 UTC vs.
Revision 1.9 by root, Sun Jul 10 22:20:55 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);
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.
… …
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 max_outstanding 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). With current Linux 2.6 versions, 4-32
73threads should be fine.
74
75Under normal circumstances you don't need to call this function, as this
76module automatically starts some threads (the exact number might change,
77and is currently 4).
78
79=item IO::AIO::max_parallel $nthreads
80
81Sets the maximum number of AIO threads to C<$nthreads>. If more than
82the specified number of threads are currently running, kill them. This
83function blocks until the limit is reached.
84
85This module automatically runs C<max_parallel 0> at program end, to ensure
86that all threads are killed and that there are no outstanding requests.
87
88Under normal circumstances you don't need to call this function.
89
90=item $oldnreqs = IO::AIO::max_outstanding $nreqs
91
92Sets the maximum number of outstanding requests to C<$nreqs>. If you
93try to queue up more than this number of requests, the caller will block until
94some requests have been handled.
95
96The default is very large, so normally there is no practical limit. If you
97queue up many requests in a loop it it often improves speed if you set
98this to a relatively low number, such as C<100>.
99
100Under normal circumstances you don't need to call this function.
101
102=item $fileno = IO::AIO::poll_fileno
103
104Return the I<request result pipe filehandle>. This filehandle must be
105polled for reading by some mechanism outside this module (e.g. Event
106or select, see below). If the pipe becomes readable you have to call
107C<poll_cb> to check the results.
108
109See C<poll_cb> for an example.
110
111=item IO::AIO::poll_cb
112
113Process all outstanding events on the result pipe. You have to call this
114regularly. Returns the number of events processed. Returns immediately
115when no events are outstanding.
116
117You can use Event to multiplex, e.g.:
118
119 Event->io (fd => IO::AIO::poll_fileno,
120 poll => 'r', async => 1,
121 cb => \&IO::AIO::poll_cb);
122
123=item IO::AIO::poll_wait
124
125Wait till the result filehandle becomes ready for reading (simply does a
126select on the filehandle. This is useful if you want to synchronously wait
127for some requests to finish).
128
129See C<nreqs> for an example.
130
131=item IO::AIO::nreqs
132
133Returns the number of requests currently outstanding.
134
135Example: wait till there are no outstanding requests anymore:
136
137 IO::AIO::poll_wait, IO::AIO::poll_cb
138 while IO::AIO::nreqs;
139 89
140=item aio_open $pathname, $flags, $mode, $callback 90=item aio_open $pathname, $flags, $mode, $callback
141 91
142Asynchronously open or create a file and call the callback with a newly 92Asynchronously open or create a file and call the callback with a newly
143created filehandle for the file. 93created filehandle for the file.
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178 128
179Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at
180offset C<0> within the scalar: 130offset C<0> within the scalar:
181 131
182 aio_read $fh, 7, 15, $buffer, 0, sub { 132 aio_read $fh, 7, 15, $buffer, 0, sub {
183 $_[0] >= 0 or die "read error: $!"; 133 $_[0] > 0 or die "read error: $!";
184 print "read <$buffer>\n"; 134 print "read $_[0] bytes: <$buffer>\n";
185 }; 135 };
186 136
187=item aio_readahead $fh,$offset,$length, $callback 137=item aio_readahead $fh,$offset,$length, $callback
188 138
189Asynchronously 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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234=item aio_fdatasync $fh, $callback 184=item aio_fdatasync $fh, $callback
235 185
236Asynchronously call fdatasync on the given filehandle and call the 186Asynchronously call fdatasync on the given filehandle and call the
237callback with the fdatasync result code. 187callback with the fdatasync result code.
238 188
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
239=cut 273=cut
240 274
241# support function to convert a fd into a perl filehandle 275# support function to convert a fd into a perl filehandle
242sub _fd2fh { 276sub _fd2fh {
243 return undef if $_[0] < 0; 277 return undef if $_[0] < 0;
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256 max_parallel 0; 290 max_parallel 0;
257} 291}
258 292
2591; 2931;
260 294
261=back
262
263=head1 BUGS
264
265 - could be optimized to use more semaphores instead of filehandles.
266
267=head1 SEE ALSO 295=head1 SEE ALSO
268 296
269L<Coro>, L<Linux::AIO>. 297L<Coro>, L<Linux::AIO>.
270 298
271=head1 AUTHOR 299=head1 AUTHOR

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