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Revision 1.77 by root, Wed Oct 25 17:57:30 2006 UTC vs.
Revision 1.121 by root, Wed Apr 16 16:45:18 2008 UTC

… …
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", O_RDONLY, 0, sub {
10 my ($fh) = @_; 10 my $fh = shift
11 or die "/etc/passwd: $!";
11 ... 12 ...
12 }; 13 };
13 14
14 aio_unlink "/tmp/file", sub { }; 15 aio_unlink "/tmp/file", sub { };
15 16
… …
25 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
26 27
27 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
28 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
29 30
30 # AnyEvent integration 31 # AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...)
31 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 32 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); 33 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35 # EV integration
36 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
33 37
34 # Event integration 38 # Event integration
35 Event->io (fd => IO::AIO::poll_fileno, 39 Event->io (fd => IO::AIO::poll_fileno,
36 poll => 'r', 40 poll => 'r',
37 cb => \&IO::AIO::poll_cb); 41 cb => \&IO::AIO::poll_cb);
… …
50 54
51=head1 DESCRIPTION 55=head1 DESCRIPTION
52 56
53This module implements asynchronous I/O using whatever means your 57This module implements asynchronous I/O using whatever means your
54operating system supports. 58operating system supports.
59
60Asynchronous means that operations that can normally block your program
61(e.g. reading from disk) will be done asynchronously: the operation
62will still block, but you can do something else in the meantime. This
63is extremely useful for programs that need to stay interactive even
64when doing heavy I/O (GUI programs, high performance network servers
65etc.), but can also be used to easily do operations in parallel that are
66normally done sequentially, e.g. stat'ing many files, which is much faster
67on a RAID volume or over NFS when you do a number of stat operations
68concurrently.
69
70While most of this works on all types of file descriptors (for
71example sockets), using these functions on file descriptors that
72support nonblocking operation (again, sockets, pipes etc.) is very
73inefficient. Use an event loop for that (such as the L<Event|Event>
74module): IO::AIO will naturally fit into such an event loop itself.
55 75
56In this version, a number of threads are started that execute your 76In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 77requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 78in perl, and the threads created by this module will not be visible
59to perl. In the future, this module might make use of the native aio 79to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 80functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 81not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 82files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 83aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 84using threads anyway.
65 85
66Although the module will work with in the presence of other (Perl-) 86Although the module will work in the presence of other (Perl-) threads,
67threads, it is currently not reentrant in any way, so use appropriate 87it is currently not reentrant in any way, so use appropriate locking
68locking yourself, always call C<poll_cb> from within the same thread, or 88yourself, always call C<poll_cb> from within the same thread, or never
69never call C<poll_cb> (or other C<aio_> functions) recursively. 89call C<poll_cb> (or other C<aio_> functions) recursively.
90
91=head2 EXAMPLE
92
93This is a simple example that uses the Event module and loads
94F</etc/passwd> asynchronously:
95
96 use Fcntl;
97 use Event;
98 use IO::AIO;
99
100 # register the IO::AIO callback with Event
101 Event->io (fd => IO::AIO::poll_fileno,
102 poll => 'r',
103 cb => \&IO::AIO::poll_cb);
104
105 # queue the request to open /etc/passwd
106 aio_open "/etc/passwd", O_RDONLY, 0, sub {
107 my $fh = shift
108 or die "error while opening: $!";
109
110 # stat'ing filehandles is generally non-blocking
111 my $size = -s $fh;
112
113 # queue a request to read the file
114 my $contents;
115 aio_read $fh, 0, $size, $contents, 0, sub {
116 $_[0] == $size
117 or die "short read: $!";
118
119 close $fh;
120
121 # file contents now in $contents
122 print $contents;
123
124 # exit event loop and program
125 Event::unloop;
126 };
127 };
128
129 # possibly queue up other requests, or open GUI windows,
130 # check for sockets etc. etc.
131
132 # process events as long as there are some:
133 Event::loop;
70 134
71=head1 REQUEST ANATOMY AND LIFETIME 135=head1 REQUEST ANATOMY AND LIFETIME
72 136
73Every C<aio_*> function creates a request. which is a C data structure not 137Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 138directly visible to Perl.
… …
116Request has reached the end of its lifetime and holds no resources anymore 180Request has reached the end of its lifetime and holds no resources anymore
117(except possibly for the Perl object, but its connection to the actual 181(except possibly for the Perl object, but its connection to the actual
118aio request is severed and calling its methods will either do nothing or 182aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 183result in a runtime error).
120 184
185=back
186
121=cut 187=cut
122 188
123package IO::AIO; 189package IO::AIO;
190
191use Carp ();
124 192
125no warnings; 193no warnings;
126use strict 'vars'; 194use strict 'vars';
127 195
128use base 'Exporter'; 196use base 'Exporter';
129 197
130BEGIN { 198BEGIN {
131 our $VERSION = '2.0'; 199 our $VERSION = '2.61';
132 200
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 201 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 202 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 203 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136 aio_group aio_nop); 204 aio_fdatasync aio_pathsync aio_readahead
205 aio_rename aio_link aio_move aio_copy aio_group
206 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
207 aio_chmod aio_utime aio_truncate);
208
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 209 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 210 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs); 211 min_parallel max_parallel max_idle
212 nreqs nready npending nthreads
213 max_poll_time max_poll_reqs);
140 214
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 216
143 require XSLoader; 217 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 218 XSLoader::load ("IO::AIO", $VERSION);
145} 219}
146 220
147=head1 FUNCTIONS 221=head1 FUNCTIONS
148 222
149=head2 AIO FUNCTIONS 223=head2 AIO REQUEST FUNCTIONS
150 224
151All the C<aio_*> calls are more or less thin wrappers around the syscall 225All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 226with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 227and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 228which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 231syscall has been executed asynchronously.
158 232
159All functions expecting a filehandle keep a copy of the filehandle 233All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 234internally until the request has finished.
161 235
162All requests return objects of type L<IO::AIO::REQ> that allow further 236All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 237further manipulation of those requests while they are in-flight.
164 238
165The pathnames you pass to these routines I<must> be absolute and 239The pathnames you pass to these routines I<must> be absolute and
166encoded in byte form. The reason for the former is that at the time the 240encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 241request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 242changed. Alternatively, you can make sure that you never change the
169current working directory. 243current working directory anywhere in the program and then use relative
244paths.
170 245
171To encode pathnames to byte form, either make sure you either: a) 246To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 247in filenames you got from outside (command line, readdir etc.) without
173etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode 248tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174your pathnames to the locale (or other) encoding in effect in the user 249your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 250environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 251use something else to ensure your scalar has the correct contents.
252
253This works, btw. independent of the internal UTF-8 bit, which IO::AIO
254handles correctly wether it is set or not.
177 255
178=over 4 256=over 4
179 257
180=item aioreq_pri $pri 258=item $prev_pri = aioreq_pri [$pri]
181 259
182Sets the priority for the next aio request. The default priority 260Returns the priority value that would be used for the next request and, if
261C<$pri> is given, sets the priority for the next aio request.
262
183is C<0>, the minimum and maximum priorities are C<-4> and C<4>, 263The default priority is C<0>, the minimum and maximum priorities are C<-4>
184respectively. Requests with higher priority will be serviced first. 264and C<4>, respectively. Requests with higher priority will be serviced
265first.
185 266
186The priority will be reset to C<0> after each call to one of the C<aio_> 267The priority will be reset to C<0> after each call to one of the C<aio_*>
187functions. 268functions.
188 269
189Example: open a file with low priority, then read something from it with 270Example: open a file with low priority, then read something from it with
190higher priority so the read request is serviced before other low priority 271higher priority so the read request is serviced before other low priority
191open requests (potentially spamming the cache): 272open requests (potentially spamming the cache):
… …
198 aio_read $_[0], ..., sub { 279 aio_read $_[0], ..., sub {
199 ... 280 ...
200 }; 281 };
201 }; 282 };
202 283
284
203=item aioreq_nice $pri_adjust 285=item aioreq_nice $pri_adjust
204 286
205Similar to C<aioreq_pri>, but subtracts the given value from the current 287Similar to C<aioreq_pri>, but subtracts the given value from the current
206priority, so effects are cumulative. 288priority, so the effect is cumulative.
289
207 290
208=item aio_open $pathname, $flags, $mode, $callback->($fh) 291=item aio_open $pathname, $flags, $mode, $callback->($fh)
209 292
210Asynchronously open or create a file and call the callback with a newly 293Asynchronously open or create a file and call the callback with a newly
211created filehandle for the file. 294created filehandle for the file.
… …
217list. They are the same as used by C<sysopen>. 300list. They are the same as used by C<sysopen>.
218 301
219Likewise, C<$mode> specifies the mode of the newly created file, if it 302Likewise, C<$mode> specifies the mode of the newly created file, if it
220didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 303didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
221except that it is mandatory (i.e. use C<0> if you don't create new files, 304except that it is mandatory (i.e. use C<0> if you don't create new files,
222and C<0666> or C<0777> if you do). 305and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
306by the umask in effect then the request is being executed, so better never
307change the umask.
223 308
224Example: 309Example:
225 310
226 aio_open "/etc/passwd", O_RDONLY, 0, sub { 311 aio_open "/etc/passwd", O_RDONLY, 0, sub {
227 if ($_[0]) { 312 if ($_[0]) {
… …
230 } else { 315 } else {
231 die "open failed: $!\n"; 316 die "open failed: $!\n";
232 } 317 }
233 }; 318 };
234 319
320
235=item aio_close $fh, $callback->($status) 321=item aio_close $fh, $callback->($status)
236 322
237Asynchronously close a file and call the callback with the result 323Asynchronously close a file and call the callback with the result
238code. I<WARNING:> although accepted, you should not pass in a perl 324code.
239filehandle here, as perl will likely close the file descriptor another
240time when the filehandle is destroyed. Normally, you can safely call perls
241C<close> or just let filehandles go out of scope.
242 325
243This is supposed to be a bug in the API, so that might change. It's 326Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
244therefore best to avoid this function. 327closing the file descriptor associated with the filehandle itself.
328
329Therefore, C<aio_close> will not close the filehandle - instead it will
330use dup2 to overwrite the file descriptor with the write-end of a pipe
331(the pipe fd will be created on demand and will be cached).
332
333Or in other words: the file descriptor will be closed, but it will not be
334free for reuse until the perl filehandle is closed.
335
336=cut
245 337
246=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
247 339
248=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
249 341
250Reads or writes C<length> bytes from the specified C<fh> and C<offset> 342Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
251into the scalar given by C<data> and offset C<dataoffset> and calls the 343into the scalar given by C<$data> and offset C<$dataoffset> and calls the
252callback without the actual number of bytes read (or -1 on error, just 344callback without the actual number of bytes read (or -1 on error, just
253like the syscall). 345like the syscall).
254 346
347If C<$offset> is undefined, then the current file descriptor offset will
348be used (and updated), otherwise the file descriptor offset will not be
349changed by these calls.
350
351If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
352
353If C<$dataoffset> is less than zero, it will be counted from the end of
354C<$data>.
355
255The C<$data> scalar I<MUST NOT> be modified in any way while the request 356The C<$data> scalar I<MUST NOT> be modified in any way while the request
256is outstanding. Modifying it can result in segfaults or WW3 (if the 357is outstanding. Modifying it can result in segfaults or World War III (if
257necessary/optional hardware is installed). 358the necessary/optional hardware is installed).
258 359
259Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 360Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
260offset C<0> within the scalar: 361offset C<0> within the scalar:
261 362
262 aio_read $fh, 7, 15, $buffer, 0, sub { 363 aio_read $fh, 7, 15, $buffer, 0, sub {
263 $_[0] > 0 or die "read error: $!"; 364 $_[0] > 0 or die "read error: $!";
264 print "read $_[0] bytes: <$buffer>\n"; 365 print "read $_[0] bytes: <$buffer>\n";
265 }; 366 };
266 367
267=item aio_move $srcpath, $dstpath, $callback->($status)
268
269Try to move the I<file> (directories not supported as either source or
270destination) from C<$srcpath> to C<$dstpath> and call the callback with
271the C<0> (error) or C<-1> ok.
272
273This is a composite request that tries to rename(2) the file first. If
274rename files with C<EXDEV>, it creates the destination file with mode 0200
275and copies the contents of the source file into it using C<aio_sendfile>,
276followed by restoring atime, mtime, access mode and uid/gid, in that
277order, and unlinking the C<$srcpath>.
278
279If an error occurs, the partial destination file will be unlinked, if
280possible, except when setting atime, mtime, access mode and uid/gid, where
281errors are being ignored.
282
283=cut
284
285sub aio_move($$$) {
286 my ($src, $dst, $cb) = @_;
287
288 my $grp = aio_group $cb;
289
290 add $grp aio_rename $src, $dst, sub {
291 if ($_[0] && $! == EXDEV) {
292 add $grp aio_open $src, O_RDONLY, 0, sub {
293 if (my $src_fh = $_[0]) {
294 my @stat = stat $src_fh;
295
296 add $grp aio_open $dst, O_WRONLY, 0200, sub {
297 if (my $dst_fh = $_[0]) {
298 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
299 close $src_fh;
300
301 if ($_[0] == $stat[7]) {
302 utime $stat[8], $stat[9], $dst;
303 chmod $stat[2] & 07777, $dst_fh;
304 chown $stat[4], $stat[5], $dst_fh;
305 close $dst_fh;
306
307 add $grp aio_unlink $src, sub {
308 $grp->result ($_[0]);
309 };
310 } else {
311 my $errno = $!;
312 add $grp aio_unlink $dst, sub {
313 $! = $errno;
314 $grp->result (-1);
315 };
316 }
317 };
318 } else {
319 $grp->result (-1);
320 }
321 },
322
323 } else {
324 $grp->result (-1);
325 }
326 };
327 } else {
328 $grp->result ($_[0]);
329 }
330 };
331
332 $grp
333}
334 368
335=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 369=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
336 370
337Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 371Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
338reading at byte offset C<$in_offset>, and starts writing at the current 372reading at byte offset C<$in_offset>, and starts writing at the current
… …
352C<$in_fh> than are written, and there is no way to find out how many 386C<$in_fh> than are written, and there is no way to find out how many
353bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 387bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
354provides the number of bytes written to C<$out_fh>. Only if the result 388provides the number of bytes written to C<$out_fh>. Only if the result
355value equals C<$length> one can assume that C<$length> bytes have been 389value equals C<$length> one can assume that C<$length> bytes have been
356read. 390read.
391
357 392
358=item aio_readahead $fh,$offset,$length, $callback->($retval) 393=item aio_readahead $fh,$offset,$length, $callback->($retval)
359 394
360C<aio_readahead> populates the page cache with data from a file so that 395C<aio_readahead> populates the page cache with data from a file so that
361subsequent reads from that file will not block on disk I/O. The C<$offset> 396subsequent reads from that file will not block on disk I/O. The C<$offset>
… …
367file. The current file offset of the file is left unchanged. 402file. The current file offset of the file is left unchanged.
368 403
369If that syscall doesn't exist (likely if your OS isn't Linux) it will be 404If that syscall doesn't exist (likely if your OS isn't Linux) it will be
370emulated by simply reading the data, which would have a similar effect. 405emulated by simply reading the data, which would have a similar effect.
371 406
407
372=item aio_stat $fh_or_path, $callback->($status) 408=item aio_stat $fh_or_path, $callback->($status)
373 409
374=item aio_lstat $fh, $callback->($status) 410=item aio_lstat $fh, $callback->($status)
375 411
376Works like perl's C<stat> or C<lstat> in void context. The callback will 412Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
389 aio_stat "/etc/passwd", sub { 425 aio_stat "/etc/passwd", sub {
390 $_[0] and die "stat failed: $!"; 426 $_[0] and die "stat failed: $!";
391 print "size is ", -s _, "\n"; 427 print "size is ", -s _, "\n";
392 }; 428 };
393 429
430
431=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
432
433Works like perl's C<utime> function (including the special case of $atime
434and $mtime being undef). Fractional times are supported if the underlying
435syscalls support them.
436
437When called with a pathname, uses utimes(2) if available, otherwise
438utime(2). If called on a file descriptor, uses futimes(2) if available,
439otherwise returns ENOSYS, so this is not portable.
440
441Examples:
442
443 # set atime and mtime to current time (basically touch(1)):
444 aio_utime "path", undef, undef;
445 # set atime to current time and mtime to beginning of the epoch:
446 aio_utime "path", time, undef; # undef==0
447
448
449=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
450
451Works like perl's C<chown> function, except that C<undef> for either $uid
452or $gid is being interpreted as "do not change" (but -1 can also be used).
453
454Examples:
455
456 # same as "chown root path" in the shell:
457 aio_chown "path", 0, -1;
458 # same as above:
459 aio_chown "path", 0, undef;
460
461
462=item aio_truncate $fh_or_path, $offset, $callback->($status)
463
464Works like truncate(2) or ftruncate(2).
465
466
467=item aio_chmod $fh_or_path, $mode, $callback->($status)
468
469Works like perl's C<chmod> function.
470
471
394=item aio_unlink $pathname, $callback->($status) 472=item aio_unlink $pathname, $callback->($status)
395 473
396Asynchronously unlink (delete) a file and call the callback with the 474Asynchronously unlink (delete) a file and call the callback with the
397result code. 475result code.
398 476
477
478=item aio_mknod $path, $mode, $dev, $callback->($status)
479
480[EXPERIMENTAL]
481
482Asynchronously create a device node (or fifo). See mknod(2).
483
484The only (POSIX-) portable way of calling this function is:
485
486 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
487
488
399=item aio_link $srcpath, $dstpath, $callback->($status) 489=item aio_link $srcpath, $dstpath, $callback->($status)
400 490
401Asynchronously create a new link to the existing object at C<$srcpath> at 491Asynchronously create a new link to the existing object at C<$srcpath> at
402the path C<$dstpath> and call the callback with the result code. 492the path C<$dstpath> and call the callback with the result code.
403 493
494
404=item aio_symlink $srcpath, $dstpath, $callback->($status) 495=item aio_symlink $srcpath, $dstpath, $callback->($status)
405 496
406Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 497Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
407the path C<$dstpath> and call the callback with the result code. 498the path C<$dstpath> and call the callback with the result code.
408 499
500
501=item aio_readlink $path, $callback->($link)
502
503Asynchronously read the symlink specified by C<$path> and pass it to
504the callback. If an error occurs, nothing or undef gets passed to the
505callback.
506
507
409=item aio_rename $srcpath, $dstpath, $callback->($status) 508=item aio_rename $srcpath, $dstpath, $callback->($status)
410 509
411Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 510Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
412rename(2) and call the callback with the result code. 511rename(2) and call the callback with the result code.
413 512
513
514=item aio_mkdir $pathname, $mode, $callback->($status)
515
516Asynchronously mkdir (create) a directory and call the callback with
517the result code. C<$mode> will be modified by the umask at the time the
518request is executed, so do not change your umask.
519
520
414=item aio_rmdir $pathname, $callback->($status) 521=item aio_rmdir $pathname, $callback->($status)
415 522
416Asynchronously rmdir (delete) a directory and call the callback with the 523Asynchronously rmdir (delete) a directory and call the callback with the
417result code. 524result code.
525
418 526
419=item aio_readdir $pathname, $callback->($entries) 527=item aio_readdir $pathname, $callback->($entries)
420 528
421Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 529Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
422directory (i.e. opendir + readdir + closedir). The entries will not be 530directory (i.e. opendir + readdir + closedir). The entries will not be
423sorted, and will B<NOT> include the C<.> and C<..> entries. 531sorted, and will B<NOT> include the C<.> and C<..> entries.
424 532
425The callback a single argument which is either C<undef> or an array-ref 533The callback a single argument which is either C<undef> or an array-ref
426with the filenames. 534with the filenames.
535
536
537=item aio_load $path, $data, $callback->($status)
538
539This is a composite request that tries to fully load the given file into
540memory. Status is the same as with aio_read.
541
542=cut
543
544sub aio_load($$;$) {
545 aio_block {
546 my ($path, undef, $cb) = @_;
547 my $data = \$_[1];
548
549 my $pri = aioreq_pri;
550 my $grp = aio_group $cb;
551
552 aioreq_pri $pri;
553 add $grp aio_open $path, O_RDONLY, 0, sub {
554 my $fh = shift
555 or return $grp->result (-1);
556
557 aioreq_pri $pri;
558 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
559 $grp->result ($_[0]);
560 };
561 };
562
563 $grp
564 }
565}
566
567=item aio_copy $srcpath, $dstpath, $callback->($status)
568
569Try to copy the I<file> (directories not supported as either source or
570destination) from C<$srcpath> to C<$dstpath> and call the callback with
571the C<0> (error) or C<-1> ok.
572
573This is a composite request that it creates the destination file with
574mode 0200 and copies the contents of the source file into it using
575C<aio_sendfile>, followed by restoring atime, mtime, access mode and
576uid/gid, in that order.
577
578If an error occurs, the partial destination file will be unlinked, if
579possible, except when setting atime, mtime, access mode and uid/gid, where
580errors are being ignored.
581
582=cut
583
584sub aio_copy($$;$) {
585 aio_block {
586 my ($src, $dst, $cb) = @_;
587
588 my $pri = aioreq_pri;
589 my $grp = aio_group $cb;
590
591 aioreq_pri $pri;
592 add $grp aio_open $src, O_RDONLY, 0, sub {
593 if (my $src_fh = $_[0]) {
594 my @stat = stat $src_fh;
595
596 aioreq_pri $pri;
597 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
598 if (my $dst_fh = $_[0]) {
599 aioreq_pri $pri;
600 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
601 if ($_[0] == $stat[7]) {
602 $grp->result (0);
603 close $src_fh;
604
605 # those should not normally block. should. should.
606 utime $stat[8], $stat[9], $dst;
607 chmod $stat[2] & 07777, $dst_fh;
608 chown $stat[4], $stat[5], $dst_fh;
609
610 aioreq_pri $pri;
611 add $grp aio_close $dst_fh;
612 } else {
613 $grp->result (-1);
614 close $src_fh;
615 close $dst_fh;
616
617 aioreq $pri;
618 add $grp aio_unlink $dst;
619 }
620 };
621 } else {
622 $grp->result (-1);
623 }
624 },
625
626 } else {
627 $grp->result (-1);
628 }
629 };
630
631 $grp
632 }
633}
634
635=item aio_move $srcpath, $dstpath, $callback->($status)
636
637Try to move the I<file> (directories not supported as either source or
638destination) from C<$srcpath> to C<$dstpath> and call the callback with
639the C<0> (error) or C<-1> ok.
640
641This is a composite request that tries to rename(2) the file first. If
642rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
643that is successful, unlinking the C<$srcpath>.
644
645=cut
646
647sub aio_move($$;$) {
648 aio_block {
649 my ($src, $dst, $cb) = @_;
650
651 my $pri = aioreq_pri;
652 my $grp = aio_group $cb;
653
654 aioreq_pri $pri;
655 add $grp aio_rename $src, $dst, sub {
656 if ($_[0] && $! == EXDEV) {
657 aioreq_pri $pri;
658 add $grp aio_copy $src, $dst, sub {
659 $grp->result ($_[0]);
660
661 if (!$_[0]) {
662 aioreq_pri $pri;
663 add $grp aio_unlink $src;
664 }
665 };
666 } else {
667 $grp->result ($_[0]);
668 }
669 };
670
671 $grp
672 }
673}
427 674
428=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 675=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
429 676
430Scans a directory (similar to C<aio_readdir>) but additionally tries to 677Scans a directory (similar to C<aio_readdir>) but additionally tries to
431efficiently separate the entries of directory C<$path> into two sets of 678efficiently separate the entries of directory C<$path> into two sets of
… …
433recurse into (everything else, including symlinks to directories). 680recurse into (everything else, including symlinks to directories).
434 681
435C<aio_scandir> is a composite request that creates of many sub requests_ 682C<aio_scandir> is a composite request that creates of many sub requests_
436C<$maxreq> specifies the maximum number of outstanding aio requests that 683C<$maxreq> specifies the maximum number of outstanding aio requests that
437this function generates. If it is C<< <= 0 >>, then a suitable default 684this function generates. If it is C<< <= 0 >>, then a suitable default
438will be chosen (currently 6). 685will be chosen (currently 4).
439 686
440On error, the callback is called without arguments, otherwise it receives 687On error, the callback is called without arguments, otherwise it receives
441two array-refs with path-relative entry names. 688two array-refs with path-relative entry names.
442 689
443Example: 690Example:
… …
477as those tend to return 0 or 1 as link counts, which disables the 724as those tend to return 0 or 1 as link counts, which disables the
478directory counting heuristic. 725directory counting heuristic.
479 726
480=cut 727=cut
481 728
482sub aio_scandir($$$) { 729sub aio_scandir($$;$) {
730 aio_block {
483 my ($path, $maxreq, $cb) = @_; 731 my ($path, $maxreq, $cb) = @_;
484 732
733 my $pri = aioreq_pri;
734
485 my $grp = aio_group $cb; 735 my $grp = aio_group $cb;
486 736
487 $maxreq = 6 if $maxreq <= 0; 737 $maxreq = 4 if $maxreq <= 0;
488 738
489 # stat once 739 # stat once
740 aioreq_pri $pri;
490 add $grp aio_stat $path, sub { 741 add $grp aio_stat $path, sub {
491 return $grp->result () if $_[0]; 742 return $grp->result () if $_[0];
492 my $now = time; 743 my $now = time;
493 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 744 my $hash1 = join ":", (stat _)[0,1,3,7,9];
494 745
495 # read the directory entries 746 # read the directory entries
747 aioreq_pri $pri;
496 add $grp aio_readdir $path, sub { 748 add $grp aio_readdir $path, sub {
497 my $entries = shift 749 my $entries = shift
498 or return $grp->result (); 750 or return $grp->result ();
499 751
500 # stat the dir another time 752 # stat the dir another time
753 aioreq_pri $pri;
501 add $grp aio_stat $path, sub { 754 add $grp aio_stat $path, sub {
502 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 755 my $hash2 = join ":", (stat _)[0,1,3,7,9];
503 756
504 my $ndirs; 757 my $ndirs;
505 758
506 # take the slow route if anything looks fishy 759 # take the slow route if anything looks fishy
507 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 760 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
508 $ndirs = -1; 761 $ndirs = -1;
509 } else { 762 } else {
510 # if nlink == 2, we are finished 763 # if nlink == 2, we are finished
511 # on non-posix-fs's, we rely on nlink < 2 764 # on non-posix-fs's, we rely on nlink < 2
512 $ndirs = (stat _)[3] - 2 765 $ndirs = (stat _)[3] - 2
513 or return $grp->result ([], $entries); 766 or return $grp->result ([], $entries);
514 } 767 }
515 768
516 # sort into likely dirs and likely nondirs 769 # sort into likely dirs and likely nondirs
517 # dirs == files without ".", short entries first 770 # dirs == files without ".", short entries first
518 $entries = [map $_->[0], 771 $entries = [map $_->[0],
519 sort { $b->[1] cmp $a->[1] } 772 sort { $b->[1] cmp $a->[1] }
520 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 773 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
521 @$entries]; 774 @$entries];
522 775
523 my (@dirs, @nondirs); 776 my (@dirs, @nondirs);
524 777
525 my $statgrp = add $grp aio_group sub { 778 my $statgrp = add $grp aio_group sub {
526 $grp->result (\@dirs, \@nondirs); 779 $grp->result (\@dirs, \@nondirs);
527 }; 780 };
528 781
529 limit $statgrp $maxreq; 782 limit $statgrp $maxreq;
530 feed $statgrp sub { 783 feed $statgrp sub {
531 return unless @$entries; 784 return unless @$entries;
532 my $entry = pop @$entries; 785 my $entry = pop @$entries;
533 786
787 aioreq_pri $pri;
534 add $statgrp aio_stat "$path/$entry/.", sub { 788 add $statgrp aio_stat "$path/$entry/.", sub {
535 if ($_[0] < 0) { 789 if ($_[0] < 0) {
536 push @nondirs, $entry; 790 push @nondirs, $entry;
537 } else { 791 } else {
538 # need to check for real directory 792 # need to check for real directory
793 aioreq_pri $pri;
539 add $statgrp aio_lstat "$path/$entry", sub { 794 add $statgrp aio_lstat "$path/$entry", sub {
540 if (-d _) { 795 if (-d _) {
541 push @dirs, $entry; 796 push @dirs, $entry;
542 797
543 unless (--$ndirs) { 798 unless (--$ndirs) {
544 push @nondirs, @$entries; 799 push @nondirs, @$entries;
545 feed $statgrp; 800 feed $statgrp;
801 }
802 } else {
803 push @nondirs, $entry;
546 } 804 }
547 } else {
548 push @nondirs, $entry;
549 } 805 }
550 } 806 }
551 } 807 };
552 }; 808 };
553 }; 809 };
554 }; 810 };
555 }; 811 };
812
813 $grp
556 }; 814 }
557
558 $grp
559} 815}
816
817=item aio_rmtree $path, $callback->($status)
818
819Delete a directory tree starting (and including) C<$path>, return the
820status of the final C<rmdir> only. This is a composite request that
821uses C<aio_scandir> to recurse into and rmdir directories, and unlink
822everything else.
823
824=cut
825
826sub aio_rmtree;
827sub aio_rmtree($;$) {
828 aio_block {
829 my ($path, $cb) = @_;
830
831 my $pri = aioreq_pri;
832 my $grp = aio_group $cb;
833
834 aioreq_pri $pri;
835 add $grp aio_scandir $path, 0, sub {
836 my ($dirs, $nondirs) = @_;
837
838 my $dirgrp = aio_group sub {
839 add $grp aio_rmdir $path, sub {
840 $grp->result ($_[0]);
841 };
842 };
843
844 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
845 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
846
847 add $grp $dirgrp;
848 };
849
850 $grp
851 }
852}
853
854=item aio_sync $callback->($status)
855
856Asynchronously call sync and call the callback when finished.
560 857
561=item aio_fsync $fh, $callback->($status) 858=item aio_fsync $fh, $callback->($status)
562 859
563Asynchronously call fsync on the given filehandle and call the callback 860Asynchronously call fsync on the given filehandle and call the callback
564with the fsync result code. 861with the fsync result code.
… …
568Asynchronously call fdatasync on the given filehandle and call the 865Asynchronously call fdatasync on the given filehandle and call the
569callback with the fdatasync result code. 866callback with the fdatasync result code.
570 867
571If this call isn't available because your OS lacks it or it couldn't be 868If this call isn't available because your OS lacks it or it couldn't be
572detected, it will be emulated by calling C<fsync> instead. 869detected, it will be emulated by calling C<fsync> instead.
870
871=item aio_pathsync $path, $callback->($status)
872
873This request tries to open, fsync and close the given path. This is a
874composite request intended tosync directories after directory operations
875(E.g. rename). This might not work on all operating systems or have any
876specific effect, but usually it makes sure that directory changes get
877written to disc. It works for anything that can be opened for read-only,
878not just directories.
879
880Passes C<0> when everything went ok, and C<-1> on error.
881
882=cut
883
884sub aio_pathsync($;$) {
885 aio_block {
886 my ($path, $cb) = @_;
887
888 my $pri = aioreq_pri;
889 my $grp = aio_group $cb;
890
891 aioreq_pri $pri;
892 add $grp aio_open $path, O_RDONLY, 0, sub {
893 my ($fh) = @_;
894 if ($fh) {
895 aioreq_pri $pri;
896 add $grp aio_fsync $fh, sub {
897 $grp->result ($_[0]);
898
899 aioreq_pri $pri;
900 add $grp aio_close $fh;
901 };
902 } else {
903 $grp->result (-1);
904 }
905 };
906
907 $grp
908 }
909}
573 910
574=item aio_group $callback->(...) 911=item aio_group $callback->(...)
575 912
576This is a very special aio request: Instead of doing something, it is a 913This is a very special aio request: Instead of doing something, it is a
577container for other aio requests, which is useful if you want to bundle 914container for other aio requests, which is useful if you want to bundle
… …
714itself. Useful when you queued a lot of events but got a result early. 1051itself. Useful when you queued a lot of events but got a result early.
715 1052
716=item $grp->result (...) 1053=item $grp->result (...)
717 1054
718Set the result value(s) that will be passed to the group callback when all 1055Set the result value(s) that will be passed to the group callback when all
719subrequests have finished. By default, no argument will be passed. 1056subrequests have finished and set the groups errno to the current value
1057of errno (just like calling C<errno> without an error number). By default,
1058no argument will be passed and errno is zero.
1059
1060=item $grp->errno ([$errno])
1061
1062Sets the group errno value to C<$errno>, or the current value of errno
1063when the argument is missing.
1064
1065Every aio request has an associated errno value that is restored when
1066the callback is invoked. This method lets you change this value from its
1067default (0).
1068
1069Calling C<result> will also set errno, so make sure you either set C<$!>
1070before the call to C<result>, or call c<errno> after it.
720 1071
721=item feed $grp $callback->($grp) 1072=item feed $grp $callback->($grp)
722 1073
723Sets a feeder/generator on this group: every group can have an attached 1074Sets a feeder/generator on this group: every group can have an attached
724generator that generates requests if idle. The idea behind this is that, 1075generator that generates requests if idle. The idea behind this is that,
… …
763 1114
764=back 1115=back
765 1116
766=head2 SUPPORT FUNCTIONS 1117=head2 SUPPORT FUNCTIONS
767 1118
1119=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1120
768=over 4 1121=over 4
769 1122
770=item $fileno = IO::AIO::poll_fileno 1123=item $fileno = IO::AIO::poll_fileno
771 1124
772Return the I<request result pipe file descriptor>. This filehandle must be 1125Return the I<request result pipe file descriptor>. This filehandle must be
… …
776 1129
777See C<poll_cb> for an example. 1130See C<poll_cb> for an example.
778 1131
779=item IO::AIO::poll_cb 1132=item IO::AIO::poll_cb
780 1133
781Process all outstanding events on the result pipe. You have to call this 1134Process some outstanding events on the result pipe. You have to call this
782regularly. Returns the number of events processed. Returns immediately 1135regularly. Returns the number of events processed. Returns immediately
783when no events are outstanding. 1136when no events are outstanding. The amount of events processed depends on
1137the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1138
1139If not all requests were processed for whatever reason, the filehandle
1140will still be ready when C<poll_cb> returns.
784 1141
785Example: Install an Event watcher that automatically calls 1142Example: Install an Event watcher that automatically calls
786IO::AIO::poll_cb with high priority: 1143IO::AIO::poll_cb with high priority:
787 1144
788 Event->io (fd => IO::AIO::poll_fileno, 1145 Event->io (fd => IO::AIO::poll_fileno,
789 poll => 'r', async => 1, 1146 poll => 'r', async => 1,
790 cb => \&IO::AIO::poll_cb); 1147 cb => \&IO::AIO::poll_cb);
791 1148
1149=item IO::AIO::max_poll_reqs $nreqs
1150
1151=item IO::AIO::max_poll_time $seconds
1152
1153These set the maximum number of requests (default C<0>, meaning infinity)
1154that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1155the maximum amount of time (default C<0>, meaning infinity) spent in
1156C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1157of time C<poll_cb> is allowed to use).
1158
1159Setting C<max_poll_time> to a non-zero value creates an overhead of one
1160syscall per request processed, which is not normally a problem unless your
1161callbacks are really really fast or your OS is really really slow (I am
1162not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1163
1164Setting these is useful if you want to ensure some level of
1165interactiveness when perl is not fast enough to process all requests in
1166time.
1167
1168For interactive programs, values such as C<0.01> to C<0.1> should be fine.
1169
1170Example: Install an Event watcher that automatically calls
1171IO::AIO::poll_cb with low priority, to ensure that other parts of the
1172program get the CPU sometimes even under high AIO load.
1173
1174 # try not to spend much more than 0.1s in poll_cb
1175 IO::AIO::max_poll_time 0.1;
1176
1177 # use a low priority so other tasks have priority
1178 Event->io (fd => IO::AIO::poll_fileno,
1179 poll => 'r', nice => 1,
1180 cb => &IO::AIO::poll_cb);
1181
792=item IO::AIO::poll_wait 1182=item IO::AIO::poll_wait
793 1183
1184If there are any outstanding requests and none of them in the result
794Wait till the result filehandle becomes ready for reading (simply does a 1185phase, wait till the result filehandle becomes ready for reading (simply
795C<select> on the filehandle. This is useful if you want to synchronously wait 1186does a C<select> on the filehandle. This is useful if you want to
796for some requests to finish). 1187synchronously wait for some requests to finish).
797 1188
798See C<nreqs> for an example. 1189See C<nreqs> for an example.
799 1190
1191=item IO::AIO::poll
1192
1193Waits until some requests have been handled.
1194
1195Returns the number of requests processed, but is otherwise strictly
1196equivalent to:
1197
1198 IO::AIO::poll_wait, IO::AIO::poll_cb
1199
800=item IO::AIO::nreqs 1200=item IO::AIO::flush
801 1201
802Returns the number of requests currently outstanding (i.e. for which their 1202Wait till all outstanding AIO requests have been handled.
803callback has not been invoked yet).
804 1203
805Example: wait till there are no outstanding requests anymore: 1204Strictly equivalent to:
806 1205
807 IO::AIO::poll_wait, IO::AIO::poll_cb 1206 IO::AIO::poll_wait, IO::AIO::poll_cb
808 while IO::AIO::nreqs; 1207 while IO::AIO::nreqs;
809 1208
810=item IO::AIO::flush 1209=back
811 1210
812Wait till all outstanding AIO requests have been handled. 1211=head3 CONTROLLING THE NUMBER OF THREADS
813 1212
814Strictly equivalent to: 1213=over
815
816 IO::AIO::poll_wait, IO::AIO::poll_cb
817 while IO::AIO::nreqs;
818
819=item IO::AIO::poll
820
821Waits until some requests have been handled.
822
823Strictly equivalent to:
824
825 IO::AIO::poll_wait, IO::AIO::poll_cb
826 if IO::AIO::nreqs;
827 1214
828=item IO::AIO::min_parallel $nthreads 1215=item IO::AIO::min_parallel $nthreads
829 1216
830Set the minimum number of AIO threads to C<$nthreads>. The current 1217Set the minimum number of AIO threads to C<$nthreads>. The current
831default is C<8>, which means eight asynchronous operations can execute 1218default is C<8>, which means eight asynchronous operations can execute
832concurrently at any one time (the number of outstanding requests, 1219concurrently at any one time (the number of outstanding requests,
833however, is unlimited). 1220however, is unlimited).
834 1221
835IO::AIO starts threads only on demand, when an AIO request is queued and 1222IO::AIO starts threads only on demand, when an AIO request is queued and
836no free thread exists. 1223no free thread exists. Please note that queueing up a hundred requests can
1224create demand for a hundred threads, even if it turns out that everything
1225is in the cache and could have been processed faster by a single thread.
837 1226
838It is recommended to keep the number of threads relatively low, as some 1227It is recommended to keep the number of threads relatively low, as some
839Linux kernel versions will scale negatively with the number of threads 1228Linux kernel versions will scale negatively with the number of threads
840(higher parallelity => MUCH higher latency). With current Linux 2.6 1229(higher parallelity => MUCH higher latency). With current Linux 2.6
841versions, 4-32 threads should be fine. 1230versions, 4-32 threads should be fine.
… …
855This module automatically runs C<max_parallel 0> at program end, to ensure 1244This module automatically runs C<max_parallel 0> at program end, to ensure
856that all threads are killed and that there are no outstanding requests. 1245that all threads are killed and that there are no outstanding requests.
857 1246
858Under normal circumstances you don't need to call this function. 1247Under normal circumstances you don't need to call this function.
859 1248
1249=item IO::AIO::max_idle $nthreads
1250
1251Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1252threads that did not get a request to process within 10 seconds). That
1253means if a thread becomes idle while C<$nthreads> other threads are also
1254idle, it will free its resources and exit.
1255
1256This is useful when you allow a large number of threads (e.g. 100 or 1000)
1257to allow for extremely high load situations, but want to free resources
1258under normal circumstances (1000 threads can easily consume 30MB of RAM).
1259
1260The default is probably ok in most situations, especially if thread
1261creation is fast. If thread creation is very slow on your system you might
1262want to use larger values.
1263
860=item $oldnreqs = IO::AIO::max_outstanding $nreqs 1264=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
861 1265
862[REMOVED] 1266This is a very bad function to use in interactive programs because it
1267blocks, and a bad way to reduce concurrency because it is inexact: Better
1268use an C<aio_group> together with a feed callback.
863 1269
864Pre-2.x versions used max_outstanding for a crude request queue length limit.
865
866In 2.x+ you are advised to use a group and a feeder to limit
867concurrency. The max_outstanding feature ran very unstable (endless
868recursions causing segfaults, bad interaction with groups etc.) and was
869removed.
870
871I am deeply sorry, but I am still on the hunt for a good limiting interface.
872
873Original description was as follows:
874
875Sets the maximum number of outstanding requests to C<$nreqs>. If you try 1270Sets the maximum number of outstanding requests to C<$nreqs>. If you
876to queue up more than this number of requests, the caller will block until 1271do queue up more than this number of requests, the next call to the
877some requests have been handled. 1272C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1273function will block until the limit is no longer exceeded.
1274
1275The default value is very large, so there is no practical limit on the
1276number of outstanding requests.
1277
1278You can still queue as many requests as you want. Therefore,
1279C<max_oustsanding> is mainly useful in simple scripts (with low values) or
1280as a stop gap to shield against fatal memory overflow (with large values).
878 1281
879=back 1282=back
880 1283
1284=head3 STATISTICAL INFORMATION
1285
1286=over
1287
1288=item IO::AIO::nreqs
1289
1290Returns the number of requests currently in the ready, execute or pending
1291states (i.e. for which their callback has not been invoked yet).
1292
1293Example: wait till there are no outstanding requests anymore:
1294
1295 IO::AIO::poll_wait, IO::AIO::poll_cb
1296 while IO::AIO::nreqs;
1297
1298=item IO::AIO::nready
1299
1300Returns the number of requests currently in the ready state (not yet
1301executed).
1302
1303=item IO::AIO::npending
1304
1305Returns the number of requests currently in the pending state (executed,
1306but not yet processed by poll_cb).
1307
1308=back
1309
881=cut 1310=cut
882 1311
883# support function to convert a fd into a perl filehandle
884sub _fd2fh {
885 return undef if $_[0] < 0;
886
887 # try to generate nice filehandles
888 my $sym = "IO::AIO::fd#$_[0]";
889 local *$sym;
890
891 open *$sym, "+<&=$_[0]" # usually works under any unix
892 or open *$sym, "<&=$_[0]" # cygwin needs this
893 or open *$sym, ">&=$_[0]" # or this
894 or return undef;
895
896 *$sym
897}
898
899min_parallel 8; 1312min_parallel 8;
900 1313
901END { 1314END { flush }
902 max_parallel 0;
903}
904 1315
9051; 13161;
906 1317
907=head2 FORK BEHAVIOUR 1318=head2 FORK BEHAVIOUR
908 1319
… …
928bytes of memory. In addition, stat requests need a stat buffer (possibly 1339bytes of memory. In addition, stat requests need a stat buffer (possibly
929a few hundred bytes), readdir requires a result buffer and so on. Perl 1340a few hundred bytes), readdir requires a result buffer and so on. Perl
930scalars and other data passed into aio requests will also be locked and 1341scalars and other data passed into aio requests will also be locked and
931will consume memory till the request has entered the done state. 1342will consume memory till the request has entered the done state.
932 1343
933This is now awfully much, so queuing lots of requests is not usually a 1344This is not awfully much, so queuing lots of requests is not usually a
934problem. 1345problem.
935 1346
936Per-thread usage: 1347Per-thread usage:
937 1348
938In the execution phase, some aio requests require more memory for 1349In the execution phase, some aio requests require more memory for

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