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Revision 1.10 by root, Sun Jul 10 23:45:16 2005 UTC vs.
Revision 1.30 by root, Wed Aug 17 04:47:38 2005 UTC

… …
22 poll => 'r', 22 poll => 'r',
23 cb => \&IO::AIO::poll_cb); 23 cb => \&IO::AIO::poll_cb);
24 24
25 # Glib/Gtk2 25 # Glib/Gtk2
26 add_watch Glib::IO IO::AIO::poll_fileno, 26 add_watch Glib::IO IO::AIO::poll_fileno,
27 \&IO::AIO::poll_cb; 27 in => sub { IO::AIO::poll_cb; 1 };
28 28
29 # Tk 29 # Tk
30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", 30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
31 readable => \&IO::AIO::poll_cb); 31 readable => \&IO::AIO::poll_cb);
32
33 # Danga::Socket
34 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
35 \&IO::AIO::poll_cb);
36
32 37
33=head1 DESCRIPTION 38=head1 DESCRIPTION
34 39
35This module implements asynchronous I/O using whatever means your 40This module implements asynchronous I/O using whatever means your
36operating system supports. 41operating system supports.
… …
43not well-supported (Linux doesn't allow them on normal files currently, 48not well-supported (Linux doesn't allow them on normal files currently,
44for example), and they would only support aio_read and aio_write, so the 49for example), and they would only support aio_read and aio_write, so the
45remaining functionality would have to be implemented using threads anyway. 50remaining functionality would have to be implemented using threads anyway.
46 51
47Although 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
48currently not reentrant, so use appropriate locking yourself. 53currently not reentrant, so use appropriate locking yourself, always call
54C<poll_cb> from within the same thread, or never call C<poll_cb> (or other
55C<aio_> functions) recursively.
49 56
50=cut 57=cut
51 58
52package IO::AIO; 59package IO::AIO;
53 60
61no warnings;
62
54use base 'Exporter'; 63use base 'Exporter';
55 64
56use Fcntl (); 65use Fcntl ();
57 66
58BEGIN { 67BEGIN {
59 $VERSION = 0.3; 68 $VERSION = 1.2;
60 69
61 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 70 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
62 aio_fsync aio_fdatasync aio_readahead); 71 aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead);
63 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 72 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
64 73
65 require XSLoader; 74 require XSLoader;
66 XSLoader::load IO::AIO, $VERSION; 75 XSLoader::load IO::AIO, $VERSION;
67} 76}
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70 79
71=head2 AIO FUNCTIONS 80=head2 AIO FUNCTIONS
72 81
73All the C<aio_*> calls are more or less thin wrappers around the syscall 82All the C<aio_*> calls are more or less thin wrappers around the syscall
74with the same name (sans C<aio_>). The arguments are similar or identical, 83with the same name (sans C<aio_>). The arguments are similar or identical,
75and they all accept an additional C<$callback> argument which must be 84and they all accept an additional (and optional) C<$callback> argument
76a code reference. This code reference will get called with the syscall 85which must be a code reference. This code reference will get called with
77return code (e.g. most syscalls return C<-1> on error, unlike perl, which 86the syscall return code (e.g. most syscalls return C<-1> on error, unlike
78usually delivers "false") as it's sole argument when the given syscall has 87perl, which usually delivers "false") as it's sole argument when the given
79been executed asynchronously. 88syscall has been executed asynchronously.
80 89
81All functions that expect a filehandle will also accept a file descriptor. 90All functions expecting a filehandle keep a copy of the filehandle
91internally until the request has finished.
82 92
83The filenames you pass to these routines I<must> be absolute. The reason 93The pathnames you pass to these routines I<must> be absolute and
84is that at the time the request is being executed, the current working 94encoded in byte form. The reason for the former is that at the time the
85directory could have changed. Alternatively, you can make sure that you 95request is being executed, the current working directory could have
96changed. Alternatively, you can make sure that you never change the
86never change the current working directory. 97current working directory.
98
99To encode pathnames to byte form, either make sure you either: a)
100always pass in filenames you got from outside (command line, readdir
101etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
102your pathnames to the locale (or other) encoding in effect in the user
103environment, d) use Glib::filename_from_unicode on unicode filenames or e)
104use something else.
87 105
88=over 4 106=over 4
89 107
90=item aio_open $pathname, $flags, $mode, $callback 108=item aio_open $pathname, $flags, $mode, $callback
91 109
… …
93created filehandle for the file. 111created filehandle for the file.
94 112
95The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 113The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
96for an explanation. 114for an explanation.
97 115
98The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 116The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
99list. They are the same as used in C<sysopen>. 117list. They are the same as used by C<sysopen>.
118
119Likewise, C<$mode> specifies the mode of the newly created file, if it
120didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
121except that it is mandatory (i.e. use C<0> if you don't create new files,
122and C<0666> or C<0777> if you do).
100 123
101Example: 124Example:
102 125
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 126 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 if ($_[0]) { 127 if ($_[0]) {
… …
111 134
112=item aio_close $fh, $callback 135=item aio_close $fh, $callback
113 136
114Asynchronously close a file and call the callback with the result 137Asynchronously close a file and call the callback with the result
115code. I<WARNING:> although accepted, you should not pass in a perl 138code. I<WARNING:> although accepted, you should not pass in a perl
116filehandle here, as perl will likely close the file descriptor itself when 139filehandle here, as perl will likely close the file descriptor another
117the filehandle is destroyed. Normally, you can safely call perls C<close> 140time when the filehandle is destroyed. Normally, you can safely call perls
118or just let filehandles go out of scope. 141C<close> or just let filehandles go out of scope.
142
143This is supposed to be a bug in the API, so that might change. It's
144therefore best to avoid this function.
119 145
120=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 146=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
121 147
122=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 148=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
123 149
124Reads or writes C<length> bytes from the specified C<fh> and C<offset> 150Reads or writes C<length> bytes from the specified C<fh> and C<offset>
125into the scalar given by C<data> and offset C<dataoffset> and calls the 151into the scalar given by C<data> and offset C<dataoffset> and calls the
126callback without the actual number of bytes read (or -1 on error, just 152callback without the actual number of bytes read (or -1 on error, just
127like the syscall). 153like the syscall).
128 154
129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 155Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
130offset C<0> within the scalar: 156offset C<0> within the scalar:
131 157
132 aio_read $fh, 7, 15, $buffer, 0, sub { 158 aio_read $fh, 7, 15, $buffer, 0, sub {
133 $_[0] > 0 or die "read error: $!"; 159 $_[0] > 0 or die "read error: $!";
134 print "read $_[0] bytes: <$buffer>\n"; 160 print "read $_[0] bytes: <$buffer>\n";
135 }; 161 };
136 162
137=item aio_readahead $fh,$offset,$length, $callback 163=item aio_readahead $fh,$offset,$length, $callback
138 164
139Asynchronously reads the specified byte range into the page cache, using
140the C<readahead> syscall. If that syscall doesn't exist the status will be
141C<-1> and C<$!> is set to ENOSYS.
142
143readahead() populates the page cache with data from a file so that 165C<aio_readahead> populates the page cache with data from a file so that
144subsequent reads from that file will not block on disk I/O. The C<$offset> 166subsequent reads from that file will not block on disk I/O. The C<$offset>
145argument specifies the starting point from which data is to be read and 167argument specifies the starting point from which data is to be read and
146C<$length> specifies the number of bytes to be read. I/O is performed in 168C<$length> specifies the number of bytes to be read. I/O is performed in
147whole pages, so that offset is effectively rounded down to a page boundary 169whole pages, so that offset is effectively rounded down to a page boundary
148and bytes are read up to the next page boundary greater than or equal to 170and bytes are read up to the next page boundary greater than or equal to
149(off-set+length). aio_readahead() does not read beyond the end of the 171(off-set+length). C<aio_readahead> does not read beyond the end of the
150file. The current file offset of the file is left unchanged. 172file. The current file offset of the file is left unchanged.
173
174If that syscall doesn't exist (likely if your OS isn't Linux) it will be
175emulated by simply reading the data, which would have a similar effect.
151 176
152=item aio_stat $fh_or_path, $callback 177=item aio_stat $fh_or_path, $callback
153 178
154=item aio_lstat $fh, $callback 179=item aio_lstat $fh, $callback
155 180
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174=item aio_unlink $pathname, $callback 199=item aio_unlink $pathname, $callback
175 200
176Asynchronously unlink (delete) a file and call the callback with the 201Asynchronously unlink (delete) a file and call the callback with the
177result code. 202result code.
178 203
204=item aio_rmdir $pathname, $callback
205
206Asynchronously rmdir (delete) a directory and call the callback with the
207result code.
208
179=item aio_fsync $fh, $callback 209=item aio_fsync $fh, $callback
180 210
181Asynchronously call fsync on the given filehandle and call the callback 211Asynchronously call fsync on the given filehandle and call the callback
182with the fsync result code. 212with the fsync result code.
183 213
184=item aio_fdatasync $fh, $callback 214=item aio_fdatasync $fh, $callback
185 215
186Asynchronously call fdatasync on the given filehandle and call the 216Asynchronously call fdatasync on the given filehandle and call the
187callback with the fdatasync result code. 217callback with the fdatasync result code.
188 218
219If this call isn't available because your OS lacks it or it couldn't be
220detected, it will be emulated by calling C<fsync> instead.
221
189=back 222=back
190 223
191=head2 SUPPORT FUNCTIONS 224=head2 SUPPORT FUNCTIONS
192 225
193=over 4 226=over 4
194 227
195=item $fileno = IO::AIO::poll_fileno 228=item $fileno = IO::AIO::poll_fileno
196 229
197Return the I<request result pipe filehandle>. This filehandle must be 230Return the I<request result pipe file descriptor>. This filehandle must be
198polled for reading by some mechanism outside this module (e.g. Event 231polled for reading by some mechanism outside this module (e.g. Event or
199or select, see below). If the pipe becomes readable you have to call 232select, see below or the SYNOPSIS). If the pipe becomes readable you have
200C<poll_cb> to check the results. 233to call C<poll_cb> to check the results.
201 234
202See C<poll_cb> for an example. 235See C<poll_cb> for an example.
203 236
204=item IO::AIO::poll_cb 237=item IO::AIO::poll_cb
205 238
206Process all outstanding events on the result pipe. You have to call this 239Process all outstanding events on the result pipe. You have to call this
207regularly. Returns the number of events processed. Returns immediately 240regularly. Returns the number of events processed. Returns immediately
208when no events are outstanding. 241when no events are outstanding.
209 242
210You can use Event to multiplex, e.g.: 243Example: Install an Event watcher that automatically calls
244IO::AIO::poll_cb with high priority:
211 245
212 Event->io (fd => IO::AIO::poll_fileno, 246 Event->io (fd => IO::AIO::poll_fileno,
213 poll => 'r', async => 1, 247 poll => 'r', async => 1,
214 cb => \&IO::AIO::poll_cb); 248 cb => \&IO::AIO::poll_cb);
215 249
216=item IO::AIO::poll_wait 250=item IO::AIO::poll_wait
217 251
218Wait till the result filehandle becomes ready for reading (simply does a 252Wait till the result filehandle becomes ready for reading (simply does a
219select on the filehandle. This is useful if you want to synchronously wait 253C<select> on the filehandle. This is useful if you want to synchronously wait
220for some requests to finish). 254for some requests to finish).
221 255
222See C<nreqs> for an example. 256See C<nreqs> for an example.
223 257
224=item IO::AIO::nreqs 258=item IO::AIO::nreqs
225 259
226Returns the number of requests currently outstanding. 260Returns the number of requests currently outstanding (i.e. for which their
261callback has not been invoked yet).
227 262
228Example: wait till there are no outstanding requests anymore: 263Example: wait till there are no outstanding requests anymore:
229 264
230 IO::AIO::poll_wait, IO::AIO::poll_cb 265 IO::AIO::poll_wait, IO::AIO::poll_cb
231 while IO::AIO::nreqs; 266 while IO::AIO::nreqs;
267
268=item IO::AIO::flush
269
270Wait till all outstanding AIO requests have been handled.
271
272Strictly equivalent to:
273
274 IO::AIO::poll_wait, IO::AIO::poll_cb
275 while IO::AIO::nreqs;
276
277=item IO::AIO::poll
278
279Waits until some requests have been handled.
280
281Strictly equivalent to:
282
283 IO::AIO::poll_wait, IO::AIO::poll_cb
284 if IO::AIO::nreqs;
232 285
233=item IO::AIO::min_parallel $nthreads 286=item IO::AIO::min_parallel $nthreads
234 287
235Set the minimum number of AIO threads to C<$nthreads>. The default is 288Set 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 289C<1>, which means a single asynchronous operation can be done at one time
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274 327
275# support function to convert a fd into a perl filehandle 328# support function to convert a fd into a perl filehandle
276sub _fd2fh { 329sub _fd2fh {
277 return undef if $_[0] < 0; 330 return undef if $_[0] < 0;
278 331
279 # try to be perl5.6-compatible 332 # try to generate nice filehandles
280 local *AIO_FH; 333 my $sym = "IO::AIO::fd#$_[0]";
281 open AIO_FH, "+<&=$_[0]" 334 local *$sym;
335
336 open *$sym, "+<&=$_[0]" # usually works under any unix
337 or open *$sym, "<&=$_[0]" # cygwin needs this
338 or open *$sym, ">&=$_[0]" # or this
282 or return undef; 339 or return undef;
283 340
284 *AIO_FH 341 *$sym
285} 342}
286 343
287min_parallel 4; 344min_parallel 4;
288 345
289END { 346END {
290 max_parallel 0; 347 max_parallel 0;
291} 348}
292 349
2931; 3501;
294 351
352=head2 FORK BEHAVIOUR
353
354Before the fork IO::AIO first handles all outstanding requests - if other
355threads add requests during this period, this time is prolonged. It then
356enters a quiescent state where no requests can be added in other threads
357and no results will be processed. After the fork the parent simply leaves
358the quiescent state and continues request processing, while the child
359starts the same number of threads as were in use by the parent.
360
295=head1 SEE ALSO 361=head1 SEE ALSO
296 362
297L<Coro>, L<Linux::AIO>. 363L<Coro>, L<Linux::AIO>.
298 364
299=head1 AUTHOR 365=head1 AUTHOR

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