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Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC vs.
Revision 1.145 by root, Sun Apr 19 19:20:10 2009 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
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
30 # AnyEvent integration 34 # EV integration
31 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 35 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
32 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33 36
34 # Event integration 37 # Event integration
35 Event->io (fd => IO::AIO::poll_fileno, 38 Event->io (fd => IO::AIO::poll_fileno,
36 poll => 'r', 39 poll => 'r',
37 cb => \&IO::AIO::poll_cb); 40 cb => \&IO::AIO::poll_cb);
… …
50 53
51=head1 DESCRIPTION 54=head1 DESCRIPTION
52 55
53This module implements asynchronous I/O using whatever means your 56This module implements asynchronous I/O using whatever means your
54operating system supports. 57operating system supports.
58
59Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even
63when doing heavy I/O (GUI programs, high performance network servers
64etc.), but can also be used to easily do operations in parallel that are
65normally done sequentially, e.g. stat'ing many files, which is much faster
66on a RAID volume or over NFS when you do a number of stat operations
67concurrently.
68
69While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very
72inefficient. Use an event loop for that (such as the L<Event|Event>
73module): IO::AIO will naturally fit into such an event loop itself.
55 74
56In this version, a number of threads are started that execute your 75In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 76requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 77in 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 78to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 79functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 80not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 81files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 82aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 83using threads anyway.
65 84
66Although the module will work with in the presence of other (Perl-) 85Although the module will work in the presence of other (Perl-) threads,
67threads, it is currently not reentrant in any way, so use appropriate 86it is currently not reentrant in any way, so use appropriate locking
68locking yourself, always call C<poll_cb> from within the same thread, or 87yourself, always call C<poll_cb> from within the same thread, or never
69never call C<poll_cb> (or other C<aio_> functions) recursively. 88call C<poll_cb> (or other C<aio_> functions) recursively.
89
90=head2 EXAMPLE
91
92This is a simple example that uses the Event module and loads
93F</etc/passwd> asynchronously:
94
95 use Fcntl;
96 use Event;
97 use IO::AIO;
98
99 # register the IO::AIO callback with Event
100 Event->io (fd => IO::AIO::poll_fileno,
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103
104 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub {
106 my $fh = shift
107 or die "error while opening: $!";
108
109 # stat'ing filehandles is generally non-blocking
110 my $size = -s $fh;
111
112 # queue a request to read the file
113 my $contents;
114 aio_read $fh, 0, $size, $contents, 0, sub {
115 $_[0] == $size
116 or die "short read: $!";
117
118 close $fh;
119
120 # file contents now in $contents
121 print $contents;
122
123 # exit event loop and program
124 Event::unloop;
125 };
126 };
127
128 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc.
130
131 # process events as long as there are some:
132 Event::loop;
70 133
71=head1 REQUEST ANATOMY AND LIFETIME 134=head1 REQUEST ANATOMY AND LIFETIME
72 135
73Every C<aio_*> function creates a request. which is a C data structure not 136Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 137directly visible to Perl.
… …
116Request has reached the end of its lifetime and holds no resources anymore 179Request 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 180(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 181aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 182result in a runtime error).
120 183
184=back
185
121=cut 186=cut
122 187
123package IO::AIO; 188package IO::AIO;
189
190use Carp ();
124 191
125no warnings; 192no warnings;
126use strict 'vars'; 193use strict 'vars';
127 194
128use base 'Exporter'; 195use base 'Exporter';
129 196
130BEGIN { 197BEGIN {
131 our $VERSION = '2.0'; 198 our $VERSION = '3.18';
132 199
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 200 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 201 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136 aio_group aio_nop); 203 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
204 aio_rename aio_link aio_move aio_copy aio_group
205 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
206 aio_chmod aio_utime aio_truncate);
207
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 210 min_parallel max_parallel max_idle
211 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs);
213
214 push @AIO_REQ, qw(aio_busy); # not exported
140 215
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 217
143 require XSLoader; 218 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 219 XSLoader::load ("IO::AIO", $VERSION);
145} 220}
146 221
147=head1 FUNCTIONS 222=head1 FUNCTIONS
148 223
149=head2 AIO FUNCTIONS 224=head2 AIO REQUEST FUNCTIONS
150 225
151All the C<aio_*> calls are more or less thin wrappers around the syscall 226All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 227with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 228and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 229which must be a code reference. This code reference will get called with
155the syscall return code (e.g. most syscalls return C<-1> on error, unlike 230the syscall return code (e.g. most syscalls return C<-1> on error, unlike
156perl, which usually delivers "false") as it's sole argument when the given 231perl, which usually delivers "false") as its sole argument after the given
157syscall has been executed asynchronously. 232syscall has been executed asynchronously.
158 233
159All functions expecting a filehandle keep a copy of the filehandle 234All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 235internally until the request has finished.
161 236
162All requests return objects of type L<IO::AIO::REQ> that allow further 237All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 238further manipulation of those requests while they are in-flight.
164 239
165The pathnames you pass to these routines I<must> be absolute and 240The 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 241encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 242request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 243changed. Alternatively, you can make sure that you never change the
169current working directory. 244current working directory anywhere in the program and then use relative
245paths.
170 246
171To encode pathnames to byte form, either make sure you either: a) 247To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 248in 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 249tinkering, 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 250your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 251environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 252use something else to ensure your scalar has the correct contents.
253
254This works, btw. independent of the internal UTF-8 bit, which IO::AIO
255handles correctly whether it is set or not.
177 256
178=over 4 257=over 4
179 258
180=item $prev_pri = aioreq_pri [$pri] 259=item $prev_pri = aioreq_pri [$pri]
181 260
… …
201 aio_read $_[0], ..., sub { 280 aio_read $_[0], ..., sub {
202 ... 281 ...
203 }; 282 };
204 }; 283 };
205 284
285
206=item aioreq_nice $pri_adjust 286=item aioreq_nice $pri_adjust
207 287
208Similar to C<aioreq_pri>, but subtracts the given value from the current 288Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 289priority, so the effect is cumulative.
290
210 291
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 292=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 293
213Asynchronously open or create a file and call the callback with a newly 294Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 295created filehandle for the file.
… …
220list. They are the same as used by C<sysopen>. 301list. They are the same as used by C<sysopen>.
221 302
222Likewise, C<$mode> specifies the mode of the newly created file, if it 303Likewise, C<$mode> specifies the mode of the newly created file, if it
223didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 304didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224except that it is mandatory (i.e. use C<0> if you don't create new files, 305except that it is mandatory (i.e. use C<0> if you don't create new files,
225and C<0666> or C<0777> if you do). 306and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
307by the umask in effect then the request is being executed, so better never
308change the umask.
226 309
227Example: 310Example:
228 311
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 312 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 313 if ($_[0]) {
… …
233 } else { 316 } else {
234 die "open failed: $!\n"; 317 die "open failed: $!\n";
235 } 318 }
236 }; 319 };
237 320
321
238=item aio_close $fh, $callback->($status) 322=item aio_close $fh, $callback->($status)
239 323
240Asynchronously close a file and call the callback with the result 324Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 325code.
242filehandle here, as perl will likely close the file descriptor another
243time when the filehandle is destroyed. Normally, you can safely call perls
244C<close> or just let filehandles go out of scope.
245 326
246This is supposed to be a bug in the API, so that might change. It's 327Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247therefore best to avoid this function. 328closing the file descriptor associated with the filehandle itself.
329
330Therefore, C<aio_close> will not close the filehandle - instead it will
331use dup2 to overwrite the file descriptor with the write-end of a pipe
332(the pipe fd will be created on demand and will be cached).
333
334Or in other words: the file descriptor will be closed, but it will not be
335free for reuse until the perl filehandle is closed.
336
337=cut
248 338
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 339=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 340
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 341=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 342
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 343Reads or writes C<$length> bytes from or to the specified C<$fh> and
254into the scalar given by C<data> and offset C<dataoffset> and calls the 344C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
255callback without the actual number of bytes read (or -1 on error, just 345and calls the callback without the actual number of bytes read (or -1 on
256like the syscall). 346error, just like the syscall).
347
348If C<$offset> is undefined, then the current file descriptor offset will
349be used (and updated), otherwise the file descriptor offset will not be
350changed by these calls.
351
352If C<$length> is undefined in C<aio_write>, use the remaining length of
353C<$data>.
354
355If C<$dataoffset> is less than zero, it will be counted from the end of
356C<$data>.
257 357
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 358The C<$data> scalar I<MUST NOT> be modified in any way while the request
259is outstanding. Modifying it can result in segfaults or WW3 (if the 359is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 360the necessary/optional hardware is installed).
261 361
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 362Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 363offset C<0> within the scalar:
264 364
265 aio_read $fh, 7, 15, $buffer, 0, sub { 365 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 366 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 367 print "read $_[0] bytes: <$buffer>\n";
268 }; 368 };
269 369
270=item aio_move $srcpath, $dstpath, $callback->($status)
271
272Try to move the I<file> (directories not supported as either source or
273destination) from C<$srcpath> to C<$dstpath> and call the callback with
274the C<0> (error) or C<-1> ok.
275
276This is a composite request that tries to rename(2) the file first. If
277rename files with C<EXDEV>, it creates the destination file with mode 0200
278and copies the contents of the source file into it using C<aio_sendfile>,
279followed by restoring atime, mtime, access mode and uid/gid, in that
280order, and unlinking the C<$srcpath>.
281
282If an error occurs, the partial destination file will be unlinked, if
283possible, except when setting atime, mtime, access mode and uid/gid, where
284errors are being ignored.
285
286=cut
287
288sub aio_move($$$) {
289 my ($src, $dst, $cb) = @_;
290
291 my $pri = aioreq_pri;
292 my $grp = aio_group $cb;
293
294 aioreq_pri $pri;
295 add $grp aio_rename $src, $dst, sub {
296 if ($_[0] && $! == EXDEV) {
297 aioreq_pri $pri;
298 add $grp aio_open $src, O_RDONLY, 0, sub {
299 if (my $src_fh = $_[0]) {
300 my @stat = stat $src_fh;
301
302 aioreq_pri $pri;
303 add $grp aio_open $dst, O_WRONLY, 0200, sub {
304 if (my $dst_fh = $_[0]) {
305 aioreq_pri $pri;
306 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
307 close $src_fh;
308
309 if ($_[0] == $stat[7]) {
310 utime $stat[8], $stat[9], $dst;
311 chmod $stat[2] & 07777, $dst_fh;
312 chown $stat[4], $stat[5], $dst_fh;
313 close $dst_fh;
314
315 aioreq_pri $pri;
316 add $grp aio_unlink $src, sub {
317 $grp->result ($_[0]);
318 };
319 } else {
320 my $errno = $!;
321 aioreq_pri $pri;
322 add $grp aio_unlink $dst, sub {
323 $! = $errno;
324 $grp->result (-1);
325 };
326 }
327 };
328 } else {
329 $grp->result (-1);
330 }
331 },
332
333 } else {
334 $grp->result (-1);
335 }
336 };
337 } else {
338 $grp->result ($_[0]);
339 }
340 };
341
342 $grp
343}
344 370
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 371=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 372
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 373Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
348reading at byte offset C<$in_offset>, and starts writing at the current 374reading at byte offset C<$in_offset>, and starts writing at the current
… …
362C<$in_fh> than are written, and there is no way to find out how many 388C<$in_fh> than are written, and there is no way to find out how many
363bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 389bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
364provides the number of bytes written to C<$out_fh>. Only if the result 390provides the number of bytes written to C<$out_fh>. Only if the result
365value equals C<$length> one can assume that C<$length> bytes have been 391value equals C<$length> one can assume that C<$length> bytes have been
366read. 392read.
393
367 394
368=item aio_readahead $fh,$offset,$length, $callback->($retval) 395=item aio_readahead $fh,$offset,$length, $callback->($retval)
369 396
370C<aio_readahead> populates the page cache with data from a file so that 397C<aio_readahead> populates the page cache with data from a file so that
371subsequent reads from that file will not block on disk I/O. The C<$offset> 398subsequent reads from that file will not block on disk I/O. The C<$offset>
… …
377file. The current file offset of the file is left unchanged. 404file. The current file offset of the file is left unchanged.
378 405
379If that syscall doesn't exist (likely if your OS isn't Linux) it will be 406If that syscall doesn't exist (likely if your OS isn't Linux) it will be
380emulated by simply reading the data, which would have a similar effect. 407emulated by simply reading the data, which would have a similar effect.
381 408
409
382=item aio_stat $fh_or_path, $callback->($status) 410=item aio_stat $fh_or_path, $callback->($status)
383 411
384=item aio_lstat $fh, $callback->($status) 412=item aio_lstat $fh, $callback->($status)
385 413
386Works like perl's C<stat> or C<lstat> in void context. The callback will 414Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
399 aio_stat "/etc/passwd", sub { 427 aio_stat "/etc/passwd", sub {
400 $_[0] and die "stat failed: $!"; 428 $_[0] and die "stat failed: $!";
401 print "size is ", -s _, "\n"; 429 print "size is ", -s _, "\n";
402 }; 430 };
403 431
432
433=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
434
435Works like perl's C<utime> function (including the special case of $atime
436and $mtime being undef). Fractional times are supported if the underlying
437syscalls support them.
438
439When called with a pathname, uses utimes(2) if available, otherwise
440utime(2). If called on a file descriptor, uses futimes(2) if available,
441otherwise returns ENOSYS, so this is not portable.
442
443Examples:
444
445 # set atime and mtime to current time (basically touch(1)):
446 aio_utime "path", undef, undef;
447 # set atime to current time and mtime to beginning of the epoch:
448 aio_utime "path", time, undef; # undef==0
449
450
451=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
452
453Works like perl's C<chown> function, except that C<undef> for either $uid
454or $gid is being interpreted as "do not change" (but -1 can also be used).
455
456Examples:
457
458 # same as "chown root path" in the shell:
459 aio_chown "path", 0, -1;
460 # same as above:
461 aio_chown "path", 0, undef;
462
463
464=item aio_truncate $fh_or_path, $offset, $callback->($status)
465
466Works like truncate(2) or ftruncate(2).
467
468
469=item aio_chmod $fh_or_path, $mode, $callback->($status)
470
471Works like perl's C<chmod> function.
472
473
404=item aio_unlink $pathname, $callback->($status) 474=item aio_unlink $pathname, $callback->($status)
405 475
406Asynchronously unlink (delete) a file and call the callback with the 476Asynchronously unlink (delete) a file and call the callback with the
407result code. 477result code.
408 478
479
480=item aio_mknod $path, $mode, $dev, $callback->($status)
481
482[EXPERIMENTAL]
483
484Asynchronously create a device node (or fifo). See mknod(2).
485
486The only (POSIX-) portable way of calling this function is:
487
488 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
489
490
409=item aio_link $srcpath, $dstpath, $callback->($status) 491=item aio_link $srcpath, $dstpath, $callback->($status)
410 492
411Asynchronously create a new link to the existing object at C<$srcpath> at 493Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 494the path C<$dstpath> and call the callback with the result code.
413 495
496
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 497=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 498
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 499Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
417the path C<$dstpath> and call the callback with the result code. 500the path C<$dstpath> and call the callback with the result code.
418 501
502
503=item aio_readlink $path, $callback->($link)
504
505Asynchronously read the symlink specified by C<$path> and pass it to
506the callback. If an error occurs, nothing or undef gets passed to the
507callback.
508
509
419=item aio_rename $srcpath, $dstpath, $callback->($status) 510=item aio_rename $srcpath, $dstpath, $callback->($status)
420 511
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 512Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 513rename(2) and call the callback with the result code.
423 514
515
516=item aio_mkdir $pathname, $mode, $callback->($status)
517
518Asynchronously mkdir (create) a directory and call the callback with
519the result code. C<$mode> will be modified by the umask at the time the
520request is executed, so do not change your umask.
521
522
424=item aio_rmdir $pathname, $callback->($status) 523=item aio_rmdir $pathname, $callback->($status)
425 524
426Asynchronously rmdir (delete) a directory and call the callback with the 525Asynchronously rmdir (delete) a directory and call the callback with the
427result code. 526result code.
527
428 528
429=item aio_readdir $pathname, $callback->($entries) 529=item aio_readdir $pathname, $callback->($entries)
430 530
431Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 531Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432directory (i.e. opendir + readdir + closedir). The entries will not be 532directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 533sorted, and will B<NOT> include the C<.> and C<..> entries.
434 534
435The callback a single argument which is either C<undef> or an array-ref 535The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 536with the filenames.
537
538
539=item aio_load $path, $data, $callback->($status)
540
541This is a composite request that tries to fully load the given file into
542memory. Status is the same as with aio_read.
543
544=cut
545
546sub aio_load($$;$) {
547 my ($path, undef, $cb) = @_;
548 my $data = \$_[1];
549
550 my $pri = aioreq_pri;
551 my $grp = aio_group $cb;
552
553 aioreq_pri $pri;
554 add $grp aio_open $path, O_RDONLY, 0, sub {
555 my $fh = shift
556 or return $grp->result (-1);
557
558 aioreq_pri $pri;
559 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
560 $grp->result ($_[0]);
561 };
562 };
563
564 $grp
565}
566
567=item aio_copy $srcpath, $dstpath, $callback->($status)
568
569Try to copy the I<file> (directories not supported as either source or
570destination) from C<$srcpath> to C<$dstpath> and call the callback with
571the C<0> (error) or C<-1> ok.
572
573This is a composite request that creates the destination file with
574mode 0200 and copies the contents of the source file into it using
575C<aio_sendfile>, followed by restoring atime, mtime, access mode and
576uid/gid, in that order.
577
578If an error occurs, the partial destination file will be unlinked, if
579possible, except when setting atime, mtime, access mode and uid/gid, where
580errors are being ignored.
581
582=cut
583
584sub aio_copy($$;$) {
585 my ($src, $dst, $cb) = @_;
586
587 my $pri = aioreq_pri;
588 my $grp = aio_group $cb;
589
590 aioreq_pri $pri;
591 add $grp aio_open $src, O_RDONLY, 0, sub {
592 if (my $src_fh = $_[0]) {
593 my @stat = stat $src_fh;
594
595 aioreq_pri $pri;
596 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
597 if (my $dst_fh = $_[0]) {
598 aioreq_pri $pri;
599 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
600 if ($_[0] == $stat[7]) {
601 $grp->result (0);
602 close $src_fh;
603
604 # those should not normally block. should. should.
605 utime $stat[8], $stat[9], $dst;
606 chmod $stat[2] & 07777, $dst_fh;
607 chown $stat[4], $stat[5], $dst_fh;
608
609 aioreq_pri $pri;
610 add $grp aio_close $dst_fh;
611 } else {
612 $grp->result (-1);
613 close $src_fh;
614 close $dst_fh;
615
616 aioreq $pri;
617 add $grp aio_unlink $dst;
618 }
619 };
620 } else {
621 $grp->result (-1);
622 }
623 },
624
625 } else {
626 $grp->result (-1);
627 }
628 };
629
630 $grp
631}
632
633=item aio_move $srcpath, $dstpath, $callback->($status)
634
635Try to move the I<file> (directories not supported as either source or
636destination) from C<$srcpath> to C<$dstpath> and call the callback with
637the C<0> (error) or C<-1> ok.
638
639This is a composite request that tries to rename(2) the file first; if
640rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
641that is successful, unlinks the C<$srcpath>.
642
643=cut
644
645sub aio_move($$;$) {
646 my ($src, $dst, $cb) = @_;
647
648 my $pri = aioreq_pri;
649 my $grp = aio_group $cb;
650
651 aioreq_pri $pri;
652 add $grp aio_rename $src, $dst, sub {
653 if ($_[0] && $! == EXDEV) {
654 aioreq_pri $pri;
655 add $grp aio_copy $src, $dst, sub {
656 $grp->result ($_[0]);
657
658 if (!$_[0]) {
659 aioreq_pri $pri;
660 add $grp aio_unlink $src;
661 }
662 };
663 } else {
664 $grp->result ($_[0]);
665 }
666 };
667
668 $grp
669}
437 670
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 671=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 672
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 673Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 674efficiently separate the entries of directory C<$path> into two sets of
… …
487as those tend to return 0 or 1 as link counts, which disables the 720as those tend to return 0 or 1 as link counts, which disables the
488directory counting heuristic. 721directory counting heuristic.
489 722
490=cut 723=cut
491 724
492sub aio_scandir($$$) { 725sub aio_scandir($$;$) {
493 my ($path, $maxreq, $cb) = @_; 726 my ($path, $maxreq, $cb) = @_;
494 727
495 my $pri = aioreq_pri; 728 my $pri = aioreq_pri;
496 729
497 my $grp = aio_group $cb; 730 my $grp = aio_group $cb;
… …
573 }; 806 };
574 807
575 $grp 808 $grp
576} 809}
577 810
811=item aio_rmtree $path, $callback->($status)
812
813Delete a directory tree starting (and including) C<$path>, return the
814status of the final C<rmdir> only. This is a composite request that
815uses C<aio_scandir> to recurse into and rmdir directories, and unlink
816everything else.
817
818=cut
819
820sub aio_rmtree;
821sub aio_rmtree($;$) {
822 my ($path, $cb) = @_;
823
824 my $pri = aioreq_pri;
825 my $grp = aio_group $cb;
826
827 aioreq_pri $pri;
828 add $grp aio_scandir $path, 0, sub {
829 my ($dirs, $nondirs) = @_;
830
831 my $dirgrp = aio_group sub {
832 add $grp aio_rmdir $path, sub {
833 $grp->result ($_[0]);
834 };
835 };
836
837 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
838 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
839
840 add $grp $dirgrp;
841 };
842
843 $grp
844}
845
846=item aio_sync $callback->($status)
847
848Asynchronously call sync and call the callback when finished.
849
578=item aio_fsync $fh, $callback->($status) 850=item aio_fsync $fh, $callback->($status)
579 851
580Asynchronously call fsync on the given filehandle and call the callback 852Asynchronously call fsync on the given filehandle and call the callback
581with the fsync result code. 853with the fsync result code.
582 854
… …
585Asynchronously call fdatasync on the given filehandle and call the 857Asynchronously call fdatasync on the given filehandle and call the
586callback with the fdatasync result code. 858callback with the fdatasync result code.
587 859
588If this call isn't available because your OS lacks it or it couldn't be 860If this call isn't available because your OS lacks it or it couldn't be
589detected, it will be emulated by calling C<fsync> instead. 861detected, it will be emulated by calling C<fsync> instead.
862
863=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
864
865Sync the data portion of the file specified by C<$offset> and C<$length>
866to disk (but NOT the metadata), by calling the Linux-specific
867sync_file_range call. If sync_file_range is not available or it returns
868ENOSYS, then fdatasync or fsync is being substituted.
869
870C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
871C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
872C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
873manpage for details.
874
875=item aio_pathsync $path, $callback->($status)
876
877This request tries to open, fsync and close the given path. This is a
878composite request intended to sync directories after directory operations
879(E.g. rename). This might not work on all operating systems or have any
880specific effect, but usually it makes sure that directory changes get
881written to disc. It works for anything that can be opened for read-only,
882not just directories.
883
884Passes C<0> when everything went ok, and C<-1> on error.
885
886=cut
887
888sub aio_pathsync($;$) {
889 my ($path, $cb) = @_;
890
891 my $pri = aioreq_pri;
892 my $grp = aio_group $cb;
893
894 aioreq_pri $pri;
895 add $grp aio_open $path, O_RDONLY, 0, sub {
896 my ($fh) = @_;
897 if ($fh) {
898 aioreq_pri $pri;
899 add $grp aio_fsync $fh, sub {
900 $grp->result ($_[0]);
901
902 aioreq_pri $pri;
903 add $grp aio_close $fh;
904 };
905 } else {
906 $grp->result (-1);
907 }
908 };
909
910 $grp
911}
590 912
591=item aio_group $callback->(...) 913=item aio_group $callback->(...)
592 914
593This is a very special aio request: Instead of doing something, it is a 915This is a very special aio request: Instead of doing something, it is a
594container for other aio requests, which is useful if you want to bundle 916container for other aio requests, which is useful if you want to bundle
… …
706Their lifetime, simplified, looks like this: when they are empty, they 1028Their lifetime, simplified, looks like this: when they are empty, they
707will finish very quickly. If they contain only requests that are in the 1029will finish very quickly. If they contain only requests that are in the
708C<done> state, they will also finish. Otherwise they will continue to 1030C<done> state, they will also finish. Otherwise they will continue to
709exist. 1031exist.
710 1032
711That means after creating a group you have some time to add requests. And 1033That means after creating a group you have some time to add requests
712in the callbacks of those requests, you can add further requests to the 1034(precisely before the callback has been invoked, which is only done within
713group. And only when all those requests have finished will the the group 1035the C<poll_cb>). And in the callbacks of those requests, you can add
714itself finish. 1036further requests to the group. And only when all those requests have
1037finished will the the group itself finish.
715 1038
716=over 4 1039=over 4
717 1040
718=item add $grp ... 1041=item add $grp ...
719 1042
… …
731itself. Useful when you queued a lot of events but got a result early. 1054itself. Useful when you queued a lot of events but got a result early.
732 1055
733=item $grp->result (...) 1056=item $grp->result (...)
734 1057
735Set the result value(s) that will be passed to the group callback when all 1058Set the result value(s) that will be passed to the group callback when all
736subrequests have finished and set thre groups errno to the current value 1059subrequests have finished and set the groups errno to the current value
737of errno (just like calling C<errno> without an error number). By default, 1060of errno (just like calling C<errno> without an error number). By default,
738no argument will be passed and errno is zero. 1061no argument will be passed and errno is zero.
739 1062
740=item $grp->errno ([$errno]) 1063=item $grp->errno ([$errno])
741 1064
… …
752=item feed $grp $callback->($grp) 1075=item feed $grp $callback->($grp)
753 1076
754Sets a feeder/generator on this group: every group can have an attached 1077Sets a feeder/generator on this group: every group can have an attached
755generator that generates requests if idle. The idea behind this is that, 1078generator that generates requests if idle. The idea behind this is that,
756although you could just queue as many requests as you want in a group, 1079although you could just queue as many requests as you want in a group,
757this might starve other requests for a potentially long time. For 1080this might starve other requests for a potentially long time. For example,
758example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1081C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
759requests, delaying any later requests for a long time. 1082delaying any later requests for a long time.
760 1083
761To avoid this, and allow incremental generation of requests, you can 1084To avoid this, and allow incremental generation of requests, you can
762instead a group and set a feeder on it that generates those requests. The 1085instead a group and set a feeder on it that generates those requests. The
763feed callback will be called whenever there are few enough (see C<limit>, 1086feed callback will be called whenever there are few enough (see C<limit>,
764below) requests active in the group itself and is expected to queue more 1087below) requests active in the group itself and is expected to queue more
… …
768not impose any limits). 1091not impose any limits).
769 1092
770If the feed does not queue more requests when called, it will be 1093If the feed does not queue more requests when called, it will be
771automatically removed from the group. 1094automatically removed from the group.
772 1095
773If the feed limit is C<0>, it will be set to C<2> automatically. 1096If the feed limit is C<0> when this method is called, it will be set to
1097C<2> automatically.
774 1098
775Example: 1099Example:
776 1100
777 # stat all files in @files, but only ever use four aio requests concurrently: 1101 # stat all files in @files, but only ever use four aio requests concurrently:
778 1102
… …
790Sets the feeder limit for the group: The feeder will be called whenever 1114Sets the feeder limit for the group: The feeder will be called whenever
791the group contains less than this many requests. 1115the group contains less than this many requests.
792 1116
793Setting the limit to C<0> will pause the feeding process. 1117Setting the limit to C<0> will pause the feeding process.
794 1118
1119The default value for the limit is C<0>, but note that setting a feeder
1120automatically bumps it up to C<2>.
1121
795=back 1122=back
796 1123
797=head2 SUPPORT FUNCTIONS 1124=head2 SUPPORT FUNCTIONS
1125
1126=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
798 1127
799=over 4 1128=over 4
800 1129
801=item $fileno = IO::AIO::poll_fileno 1130=item $fileno = IO::AIO::poll_fileno
802 1131
… …
807 1136
808See C<poll_cb> for an example. 1137See C<poll_cb> for an example.
809 1138
810=item IO::AIO::poll_cb 1139=item IO::AIO::poll_cb
811 1140
812Process all outstanding events on the result pipe. You have to call this 1141Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1142regularly. Returns C<0> if all events could be processed, or C<-1> if it
814when no events are outstanding. 1143returned earlier for whatever reason. Returns immediately when no events
1144are outstanding. The amount of events processed depends on the settings of
1145C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1146
816If not all requests were processed for whatever reason, the filehandle 1147If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1148will still be ready when C<poll_cb> returns, so normally you don't have to
1149do anything special to have it called later.
818 1150
819Example: Install an Event watcher that automatically calls 1151Example: Install an Event watcher that automatically calls
820IO::AIO::poll_cb with high priority: 1152IO::AIO::poll_cb with high priority:
821 1153
822 Event->io (fd => IO::AIO::poll_fileno, 1154 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1155 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1156 cb => \&IO::AIO::poll_cb);
825 1157
826=item IO::AIO::poll_some $max_requests 1158=item IO::AIO::max_poll_reqs $nreqs
827 1159
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1160=item IO::AIO::max_poll_time $seconds
829at a time.
830 1161
831Useful if you want to ensure some level of interactiveness when perl is 1162These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1163that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1164the maximum amount of time (default C<0>, meaning infinity) spent in
1165C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1166of time C<poll_cb> is allowed to use).
1167
1168Setting C<max_poll_time> to a non-zero value creates an overhead of one
1169syscall per request processed, which is not normally a problem unless your
1170callbacks are really really fast or your OS is really really slow (I am
1171not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1172
1173Setting these is useful if you want to ensure some level of
1174interactiveness when perl is not fast enough to process all requests in
1175time.
1176
1177For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1178
834Example: Install an Event watcher that automatically calls 1179Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1180IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1181program get the CPU sometimes even under high AIO load.
837 1182
1183 # try not to spend much more than 0.1s in poll_cb
1184 IO::AIO::max_poll_time 0.1;
1185
1186 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1187 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1188 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1189 cb => &IO::AIO::poll_cb);
841 1190
842=item IO::AIO::poll_wait 1191=item IO::AIO::poll_wait
843 1192
1193If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1194phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1195does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1196synchronously wait for some requests to finish).
847 1197
848See C<nreqs> for an example. 1198See C<nreqs> for an example.
849 1199
1200=item IO::AIO::poll
1201
1202Waits until some requests have been handled.
1203
1204Returns the number of requests processed, but is otherwise strictly
1205equivalent to:
1206
1207 IO::AIO::poll_wait, IO::AIO::poll_cb
1208
850=item IO::AIO::nreqs 1209=item IO::AIO::flush
851 1210
852Returns the number of requests currently in the ready, execute or pending 1211Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1212
855Example: wait till there are no outstanding requests anymore: 1213Strictly equivalent to:
856 1214
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1215 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1216 while IO::AIO::nreqs;
859 1217
860=item IO::AIO::nready 1218=back
861 1219
862Returns the number of requests currently in the ready state (not yet 1220=head3 CONTROLLING THE NUMBER OF THREADS
863executed).
864 1221
865=item IO::AIO::npending 1222=over
866
867Returns the number of requests currently in the pending state (executed,
868but not yet processed by poll_cb).
869
870=item IO::AIO::flush
871
872Wait till all outstanding AIO requests have been handled.
873
874Strictly equivalent to:
875
876 IO::AIO::poll_wait, IO::AIO::poll_cb
877 while IO::AIO::nreqs;
878
879=item IO::AIO::poll
880
881Waits until some requests have been handled.
882
883Strictly equivalent to:
884
885 IO::AIO::poll_wait, IO::AIO::poll_cb
886 if IO::AIO::nreqs;
887 1223
888=item IO::AIO::min_parallel $nthreads 1224=item IO::AIO::min_parallel $nthreads
889 1225
890Set the minimum number of AIO threads to C<$nthreads>. The current 1226Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1227default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1228concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1229however, is unlimited).
894 1230
895IO::AIO starts threads only on demand, when an AIO request is queued and 1231IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1232no free thread exists. Please note that queueing up a hundred requests can
1233create demand for a hundred threads, even if it turns out that everything
1234is in the cache and could have been processed faster by a single thread.
897 1235
898It is recommended to keep the number of threads relatively low, as some 1236It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1237Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1238(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1239versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1253This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1254that all threads are killed and that there are no outstanding requests.
917 1255
918Under normal circumstances you don't need to call this function. 1256Under normal circumstances you don't need to call this function.
919 1257
1258=item IO::AIO::max_idle $nthreads
1259
1260Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1261threads that did not get a request to process within 10 seconds). That
1262means if a thread becomes idle while C<$nthreads> other threads are also
1263idle, it will free its resources and exit.
1264
1265This is useful when you allow a large number of threads (e.g. 100 or 1000)
1266to allow for extremely high load situations, but want to free resources
1267under normal circumstances (1000 threads can easily consume 30MB of RAM).
1268
1269The default is probably ok in most situations, especially if thread
1270creation is fast. If thread creation is very slow on your system you might
1271want to use larger values.
1272
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1273=item IO::AIO::max_outstanding $maxreqs
921 1274
922This is a very bad function to use in interactive programs because it 1275This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1276blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1277use an C<aio_group> together with a feed callback.
925 1278
926Sets the maximum number of outstanding requests to C<$nreqs>. If you 1279Sets the maximum number of outstanding requests to C<$nreqs>. If you
927to queue up more than this number of requests, the next call to the 1280do queue up more than this number of requests, the next call to the
928C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) 1281C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
929function will block until the limit is no longer exceeded. 1282function will block until the limit is no longer exceeded.
930 1283
931The default value is very large, so there is no practical limit on the 1284The default value is very large, so there is no practical limit on the
932number of outstanding requests. 1285number of outstanding requests.
933 1286
934You can still queue as many requests as you want. Therefore, 1287You can still queue as many requests as you want. Therefore,
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1288C<max_outstanding> is mainly useful in simple scripts (with low values) or
936as a stop gap to shield against fatal memory overflow (with large values). 1289as a stop gap to shield against fatal memory overflow (with large values).
937 1290
938=back 1291=back
939 1292
1293=head3 STATISTICAL INFORMATION
1294
1295=over
1296
1297=item IO::AIO::nreqs
1298
1299Returns the number of requests currently in the ready, execute or pending
1300states (i.e. for which their callback has not been invoked yet).
1301
1302Example: wait till there are no outstanding requests anymore:
1303
1304 IO::AIO::poll_wait, IO::AIO::poll_cb
1305 while IO::AIO::nreqs;
1306
1307=item IO::AIO::nready
1308
1309Returns the number of requests currently in the ready state (not yet
1310executed).
1311
1312=item IO::AIO::npending
1313
1314Returns the number of requests currently in the pending state (executed,
1315but not yet processed by poll_cb).
1316
1317=back
1318
940=cut 1319=cut
941 1320
942# support function to convert a fd into a perl filehandle
943sub _fd2fh {
944 return undef if $_[0] < 0;
945
946 # try to generate nice filehandles
947 my $sym = "IO::AIO::fd#$_[0]";
948 local *$sym;
949
950 open *$sym, "+<&=$_[0]" # usually works under any unix
951 or open *$sym, "<&=$_[0]" # cygwin needs this
952 or open *$sym, ">&=$_[0]" # or this
953 or return undef;
954
955 *$sym
956}
957
958min_parallel 8; 1321min_parallel 8;
1322
1323END { flush }
959 1324
9601; 13251;
961 1326
962=head2 FORK BEHAVIOUR 1327=head2 FORK BEHAVIOUR
963 1328
… …
983bytes of memory. In addition, stat requests need a stat buffer (possibly 1348bytes of memory. In addition, stat requests need a stat buffer (possibly
984a few hundred bytes), readdir requires a result buffer and so on. Perl 1349a few hundred bytes), readdir requires a result buffer and so on. Perl
985scalars and other data passed into aio requests will also be locked and 1350scalars and other data passed into aio requests will also be locked and
986will consume memory till the request has entered the done state. 1351will consume memory till the request has entered the done state.
987 1352
988This is now awfully much, so queuing lots of requests is not usually a 1353This is not awfully much, so queuing lots of requests is not usually a
989problem. 1354problem.
990 1355
991Per-thread usage: 1356Per-thread usage:
992 1357
993In the execution phase, some aio requests require more memory for 1358In the execution phase, some aio requests require more memory for
… …
998 1363
999Known bugs will be fixed in the next release. 1364Known bugs will be fixed in the next release.
1000 1365
1001=head1 SEE ALSO 1366=head1 SEE ALSO
1002 1367
1003L<Coro::AIO>. 1368L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1369more natural syntax.
1004 1370
1005=head1 AUTHOR 1371=head1 AUTHOR
1006 1372
1007 Marc Lehmann <schmorp@schmorp.de> 1373 Marc Lehmann <schmorp@schmorp.de>
1008 http://home.schmorp.de/ 1374 http://home.schmorp.de/

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