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Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC vs.
Revision 1.99 by root, Sun Jan 7 21:32:20 2007 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
… …
50 51
51=head1 DESCRIPTION 52=head1 DESCRIPTION
52 53
53This module implements asynchronous I/O using whatever means your 54This module implements asynchronous I/O using whatever means your
54operating system supports. 55operating system supports.
56
57Asynchronous means that operations that can normally block your program
58(e.g. reading from disk) will be done asynchronously: the operation
59will still block, but you can do something else in the meantime. This
60is extremely useful for programs that need to stay interactive even
61when doing heavy I/O (GUI programs, high performance network servers
62etc.), but can also be used to easily do operations in parallel that are
63normally done sequentially, e.g. stat'ing many files, which is much faster
64on a RAID volume or over NFS when you do a number of stat operations
65concurrently.
66
67While most of this works on all types of file descriptors (for example
68sockets), using these functions on file descriptors that support
69nonblocking operation (again, sockets, pipes etc.) is very inefficient or
70might not work (aio_read fails on sockets/pipes/fifos). Use an event loop
71for that (such as the L<Event|Event> module): IO::AIO will naturally fit
72into such an event loop itself.
55 73
56In this version, a number of threads are started that execute your 74In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 75requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 76in 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 77to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 78functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 79not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 80files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 81aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 82using threads anyway.
65 83
66Although the module will work with in the presence of other (Perl-) 84Although the module will work with in the presence of other (Perl-)
67threads, it is currently not reentrant in any way, so use appropriate 85threads, it is currently not reentrant in any way, so use appropriate
68locking yourself, always call C<poll_cb> from within the same thread, or 86locking yourself, always call C<poll_cb> from within the same thread, or
69never call C<poll_cb> (or other C<aio_> functions) recursively. 87never call C<poll_cb> (or other C<aio_> functions) recursively.
70 88
89=head2 EXAMPLE
90
91This is a simple example that uses the Event module and loads
92F</etc/passwd> asynchronously:
93
94 use Fcntl;
95 use Event;
96 use IO::AIO;
97
98 # register the IO::AIO callback with Event
99 Event->io (fd => IO::AIO::poll_fileno,
100 poll => 'r',
101 cb => \&IO::AIO::poll_cb);
102
103 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub {
105 my $fh = shift
106 or die "error while opening: $!";
107
108 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh;
110
111 # queue a request to read the file
112 my $contents;
113 aio_read $fh, 0, $size, $contents, 0, sub {
114 $_[0] == $size
115 or die "short read: $!";
116
117 close $fh;
118
119 # file contents now in $contents
120 print $contents;
121
122 # exit event loop and program
123 Event::unloop;
124 };
125 };
126
127 # possibly queue up other requests, or open GUI windows,
128 # check for sockets etc. etc.
129
130 # process events as long as there are some:
131 Event::loop;
132
71=head1 REQUEST ANATOMY AND LIFETIME 133=head1 REQUEST ANATOMY AND LIFETIME
72 134
73Every C<aio_*> function creates a request. which is a C data structure not 135Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 136directly visible to Perl.
75 137
… …
116Request has reached the end of its lifetime and holds no resources anymore 178Request 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 179(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 180aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 181result in a runtime error).
120 182
183=back
184
121=cut 185=cut
122 186
123package IO::AIO; 187package IO::AIO;
124 188
125no warnings; 189no warnings;
126use strict 'vars'; 190use strict 'vars';
127 191
128use base 'Exporter'; 192use base 'Exporter';
129 193
130BEGIN { 194BEGIN {
131 our $VERSION = '2.0'; 195 our $VERSION = '2.32';
132 196
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 197 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
134 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 198 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 199 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
136 aio_group aio_nop); 200 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree);
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 203 min_parallel max_parallel max_idle
204 nreqs nready npending nthreads
205 max_poll_time max_poll_reqs);
140 206
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 207 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 208
143 require XSLoader; 209 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 210 XSLoader::load ("IO::AIO", $VERSION);
145} 211}
146 212
147=head1 FUNCTIONS 213=head1 FUNCTIONS
148 214
149=head2 AIO FUNCTIONS 215=head2 AIO REQUEST FUNCTIONS
150 216
151All the C<aio_*> calls are more or less thin wrappers around the syscall 217All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 218with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 219and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 220which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 223syscall has been executed asynchronously.
158 224
159All functions expecting a filehandle keep a copy of the filehandle 225All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 226internally until the request has finished.
161 227
162All requests return objects of type L<IO::AIO::REQ> that allow further 228All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 229further manipulation of those requests while they are in-flight.
164 230
165The pathnames you pass to these routines I<must> be absolute and 231The 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 232encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 233request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 234changed. Alternatively, you can make sure that you never change the
169current working directory. 235current working directory anywhere in the program and then use relative
236paths.
170 237
171To encode pathnames to byte form, either make sure you either: a) 238To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 239in 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 240tinkering, 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 241your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 242environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 243use something else to ensure your scalar has the correct contents.
244
245This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246handles correctly wether it is set or not.
177 247
178=over 4 248=over 4
179 249
180=item $prev_pri = aioreq_pri [$pri] 250=item $prev_pri = aioreq_pri [$pri]
181 251
… …
204 }; 274 };
205 275
206=item aioreq_nice $pri_adjust 276=item aioreq_nice $pri_adjust
207 277
208Similar to C<aioreq_pri>, but subtracts the given value from the current 278Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 279priority, so the effect is cumulative.
210 280
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 281=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 282
213Asynchronously open or create a file and call the callback with a newly 283Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 284created filehandle for the file.
… …
265 aio_read $fh, 7, 15, $buffer, 0, sub { 335 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 336 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 337 print "read $_[0] bytes: <$buffer>\n";
268 }; 338 };
269 339
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
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 340=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 341
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 342Tries 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 343reading at byte offset C<$in_offset>, and starts writing at the current
349file offset of C<$out_fh>. Because of that, it is not safe to issue more 344file offset of C<$out_fh>. Because of that, it is not safe to issue more
… …
404=item aio_unlink $pathname, $callback->($status) 399=item aio_unlink $pathname, $callback->($status)
405 400
406Asynchronously unlink (delete) a file and call the callback with the 401Asynchronously unlink (delete) a file and call the callback with the
407result code. 402result code.
408 403
404=item aio_mknod $path, $mode, $dev, $callback->($status)
405
406[EXPERIMENTAL]
407
408Asynchronously create a device node (or fifo). See mknod(2).
409
410The only (POSIX-) portable way of calling this function is:
411
412 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
413
409=item aio_link $srcpath, $dstpath, $callback->($status) 414=item aio_link $srcpath, $dstpath, $callback->($status)
410 415
411Asynchronously create a new link to the existing object at C<$srcpath> at 416Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 417the path C<$dstpath> and call the callback with the result code.
413 418
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 419=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 420
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 421Asynchronously 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. 422the path C<$dstpath> and call the callback with the result code.
423
424=item aio_readlink $path, $callback->($link)
425
426Asynchronously read the symlink specified by C<$path> and pass it to
427the callback. If an error occurs, nothing or undef gets passed to the
428callback.
418 429
419=item aio_rename $srcpath, $dstpath, $callback->($status) 430=item aio_rename $srcpath, $dstpath, $callback->($status)
420 431
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 432Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 433rename(2) and call the callback with the result code.
… …
432directory (i.e. opendir + readdir + closedir). The entries will not be 443directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 444sorted, and will B<NOT> include the C<.> and C<..> entries.
434 445
435The callback a single argument which is either C<undef> or an array-ref 446The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 447with the filenames.
448
449=item aio_load $path, $data, $callback->($status)
450
451This is a composite request that tries to fully load the given file into
452memory. Status is the same as with aio_read.
453
454=cut
455
456sub aio_load($$;$) {
457 aio_block {
458 my ($path, undef, $cb) = @_;
459 my $data = \$_[1];
460
461 my $pri = aioreq_pri;
462 my $grp = aio_group $cb;
463
464 aioreq_pri $pri;
465 add $grp aio_open $path, O_RDONLY, 0, sub {
466 my ($fh) = @_
467 or return $grp->result (-1);
468
469 aioreq_pri $pri;
470 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
471 $grp->result ($_[0]);
472 };
473 };
474
475 $grp
476 }
477}
478
479=item aio_copy $srcpath, $dstpath, $callback->($status)
480
481Try to copy the I<file> (directories not supported as either source or
482destination) from C<$srcpath> to C<$dstpath> and call the callback with
483the C<0> (error) or C<-1> ok.
484
485This is a composite request that it creates the destination file with
486mode 0200 and copies the contents of the source file into it using
487C<aio_sendfile>, followed by restoring atime, mtime, access mode and
488uid/gid, in that order.
489
490If an error occurs, the partial destination file will be unlinked, if
491possible, except when setting atime, mtime, access mode and uid/gid, where
492errors are being ignored.
493
494=cut
495
496sub aio_copy($$;$) {
497 aio_block {
498 my ($src, $dst, $cb) = @_;
499
500 my $pri = aioreq_pri;
501 my $grp = aio_group $cb;
502
503 aioreq_pri $pri;
504 add $grp aio_open $src, O_RDONLY, 0, sub {
505 if (my $src_fh = $_[0]) {
506 my @stat = stat $src_fh;
507
508 aioreq_pri $pri;
509 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
510 if (my $dst_fh = $_[0]) {
511 aioreq_pri $pri;
512 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
513 if ($_[0] == $stat[7]) {
514 $grp->result (0);
515 close $src_fh;
516
517 # those should not normally block. should. should.
518 utime $stat[8], $stat[9], $dst;
519 chmod $stat[2] & 07777, $dst_fh;
520 chown $stat[4], $stat[5], $dst_fh;
521 close $dst_fh;
522 } else {
523 $grp->result (-1);
524 close $src_fh;
525 close $dst_fh;
526
527 aioreq $pri;
528 add $grp aio_unlink $dst;
529 }
530 };
531 } else {
532 $grp->result (-1);
533 }
534 },
535
536 } else {
537 $grp->result (-1);
538 }
539 };
540
541 $grp
542 }
543}
544
545=item aio_move $srcpath, $dstpath, $callback->($status)
546
547Try to move the I<file> (directories not supported as either source or
548destination) from C<$srcpath> to C<$dstpath> and call the callback with
549the C<0> (error) or C<-1> ok.
550
551This is a composite request that tries to rename(2) the file first. If
552rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
553that is successful, unlinking the C<$srcpath>.
554
555=cut
556
557sub aio_move($$;$) {
558 aio_block {
559 my ($src, $dst, $cb) = @_;
560
561 my $pri = aioreq_pri;
562 my $grp = aio_group $cb;
563
564 aioreq_pri $pri;
565 add $grp aio_rename $src, $dst, sub {
566 if ($_[0] && $! == EXDEV) {
567 aioreq_pri $pri;
568 add $grp aio_copy $src, $dst, sub {
569 $grp->result ($_[0]);
570
571 if (!$_[0]) {
572 aioreq_pri $pri;
573 add $grp aio_unlink $src;
574 }
575 };
576 } else {
577 $grp->result ($_[0]);
578 }
579 };
580
581 $grp
582 }
583}
437 584
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 585=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 586
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 587Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 588efficiently separate the entries of directory C<$path> into two sets of
… …
488directory counting heuristic. 635directory counting heuristic.
489 636
490=cut 637=cut
491 638
492sub aio_scandir($$$) { 639sub aio_scandir($$$) {
640 aio_block {
493 my ($path, $maxreq, $cb) = @_; 641 my ($path, $maxreq, $cb) = @_;
494 642
495 my $pri = aioreq_pri; 643 my $pri = aioreq_pri;
496 644
497 my $grp = aio_group $cb; 645 my $grp = aio_group $cb;
498 646
499 $maxreq = 4 if $maxreq <= 0; 647 $maxreq = 4 if $maxreq <= 0;
500 648
501 # stat once 649 # stat once
502 aioreq_pri $pri;
503 add $grp aio_stat $path, sub {
504 return $grp->result () if $_[0];
505 my $now = time;
506 my $hash1 = join ":", (stat _)[0,1,3,7,9];
507
508 # read the directory entries
509 aioreq_pri $pri; 650 aioreq_pri $pri;
510 add $grp aio_readdir $path, sub { 651 add $grp aio_stat $path, sub {
511 my $entries = shift
512 or return $grp->result (); 652 return $grp->result () if $_[0];
653 my $now = time;
654 my $hash1 = join ":", (stat _)[0,1,3,7,9];
513 655
514 # stat the dir another time 656 # read the directory entries
515 aioreq_pri $pri; 657 aioreq_pri $pri;
658 add $grp aio_readdir $path, sub {
659 my $entries = shift
660 or return $grp->result ();
661
662 # stat the dir another time
663 aioreq_pri $pri;
516 add $grp aio_stat $path, sub { 664 add $grp aio_stat $path, sub {
517 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 665 my $hash2 = join ":", (stat _)[0,1,3,7,9];
518 666
519 my $ndirs; 667 my $ndirs;
520 668
521 # take the slow route if anything looks fishy 669 # take the slow route if anything looks fishy
522 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 670 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523 $ndirs = -1; 671 $ndirs = -1;
524 } else { 672 } else {
525 # if nlink == 2, we are finished 673 # if nlink == 2, we are finished
526 # on non-posix-fs's, we rely on nlink < 2 674 # on non-posix-fs's, we rely on nlink < 2
527 $ndirs = (stat _)[3] - 2 675 $ndirs = (stat _)[3] - 2
528 or return $grp->result ([], $entries); 676 or return $grp->result ([], $entries);
529 } 677 }
530 678
531 # sort into likely dirs and likely nondirs 679 # sort into likely dirs and likely nondirs
532 # dirs == files without ".", short entries first 680 # dirs == files without ".", short entries first
533 $entries = [map $_->[0], 681 $entries = [map $_->[0],
534 sort { $b->[1] cmp $a->[1] } 682 sort { $b->[1] cmp $a->[1] }
535 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 683 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536 @$entries]; 684 @$entries];
537 685
538 my (@dirs, @nondirs); 686 my (@dirs, @nondirs);
539 687
540 my $statgrp = add $grp aio_group sub { 688 my $statgrp = add $grp aio_group sub {
541 $grp->result (\@dirs, \@nondirs); 689 $grp->result (\@dirs, \@nondirs);
542 }; 690 };
543 691
544 limit $statgrp $maxreq; 692 limit $statgrp $maxreq;
545 feed $statgrp sub { 693 feed $statgrp sub {
546 return unless @$entries; 694 return unless @$entries;
547 my $entry = pop @$entries; 695 my $entry = pop @$entries;
548 696
549 aioreq_pri $pri; 697 aioreq_pri $pri;
550 add $statgrp aio_stat "$path/$entry/.", sub { 698 add $statgrp aio_stat "$path/$entry/.", sub {
551 if ($_[0] < 0) { 699 if ($_[0] < 0) {
552 push @nondirs, $entry; 700 push @nondirs, $entry;
553 } else { 701 } else {
554 # need to check for real directory 702 # need to check for real directory
555 aioreq_pri $pri; 703 aioreq_pri $pri;
556 add $statgrp aio_lstat "$path/$entry", sub { 704 add $statgrp aio_lstat "$path/$entry", sub {
557 if (-d _) { 705 if (-d _) {
558 push @dirs, $entry; 706 push @dirs, $entry;
559 707
560 unless (--$ndirs) { 708 unless (--$ndirs) {
561 push @nondirs, @$entries; 709 push @nondirs, @$entries;
562 feed $statgrp; 710 feed $statgrp;
711 }
712 } else {
713 push @nondirs, $entry;
563 } 714 }
564 } else {
565 push @nondirs, $entry;
566 } 715 }
567 } 716 }
568 } 717 };
569 }; 718 };
570 }; 719 };
571 }; 720 };
572 }; 721 };
722
723 $grp
573 }; 724 }
725}
574 726
727=item aio_rmtree $path, $callback->($status)
728
729Delete a directory tree starting (and including) C<$path>, return the status of the final C<rmdir> only.
730This is a composite request that uses C<aio_scandir> to recurse into and rmdir directories, and
731unlink everything else.
732
733=cut
734
735sub aio_rmtree;
736sub aio_rmtree {
737 aio_block {
738 my ($path, $cb) = @_;
739
740 my $pri = aioreq_pri;
741 my $grp = aio_group $cb;
742
743 aioreq_pri $pri;
744 add $grp aio_scandir $path, 0, sub {
745 my ($dirs, $nondirs) = @_;
746
747 my $dirgrp = aio_group sub {
748 add $grp aio_rmdir $path, sub {
749 $grp->result ($_[0]);
750 };
751 };
752
753 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
754 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
755
756 add $grp $dirgrp;
757 };
758
575 $grp 759 $grp
760 }
576} 761}
577 762
578=item aio_fsync $fh, $callback->($status) 763=item aio_fsync $fh, $callback->($status)
579 764
580Asynchronously call fsync on the given filehandle and call the callback 765Asynchronously call fsync on the given filehandle and call the callback
… …
794 979
795=back 980=back
796 981
797=head2 SUPPORT FUNCTIONS 982=head2 SUPPORT FUNCTIONS
798 983
984=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
985
799=over 4 986=over 4
800 987
801=item $fileno = IO::AIO::poll_fileno 988=item $fileno = IO::AIO::poll_fileno
802 989
803Return the I<request result pipe file descriptor>. This filehandle must be 990Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 994
808See C<poll_cb> for an example. 995See C<poll_cb> for an example.
809 996
810=item IO::AIO::poll_cb 997=item IO::AIO::poll_cb
811 998
812Process all outstanding events on the result pipe. You have to call this 999Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1000regularly. Returns the number of events processed. Returns immediately
814when no events are outstanding. 1001when no events are outstanding. The amount of events processed depends on
1002the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1003
816If not all requests were processed for whatever reason, the filehandle 1004If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1005will still be ready when C<poll_cb> returns.
818 1006
819Example: Install an Event watcher that automatically calls 1007Example: Install an Event watcher that automatically calls
… …
821 1009
822 Event->io (fd => IO::AIO::poll_fileno, 1010 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1011 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1012 cb => \&IO::AIO::poll_cb);
825 1013
826=item IO::AIO::poll_some $max_requests 1014=item IO::AIO::max_poll_reqs $nreqs
827 1015
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1016=item IO::AIO::max_poll_time $seconds
829at a time.
830 1017
831Useful if you want to ensure some level of interactiveness when perl is 1018These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1019that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1020the maximum amount of time (default C<0>, meaning infinity) spent in
1021C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1022of time C<poll_cb> is allowed to use).
1023
1024Setting C<max_poll_time> to a non-zero value creates an overhead of one
1025syscall per request processed, which is not normally a problem unless your
1026callbacks are really really fast or your OS is really really slow (I am
1027not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1028
1029Setting these is useful if you want to ensure some level of
1030interactiveness when perl is not fast enough to process all requests in
1031time.
1032
1033For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1034
834Example: Install an Event watcher that automatically calls 1035Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1036IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1037program get the CPU sometimes even under high AIO load.
837 1038
1039 # try not to spend much more than 0.1s in poll_cb
1040 IO::AIO::max_poll_time 0.1;
1041
1042 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1043 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1044 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1045 cb => &IO::AIO::poll_cb);
841 1046
842=item IO::AIO::poll_wait 1047=item IO::AIO::poll_wait
843 1048
1049If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1050phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1051does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1052synchronously wait for some requests to finish).
847 1053
848See C<nreqs> for an example. 1054See C<nreqs> for an example.
849 1055
1056=item IO::AIO::poll
1057
1058Waits until some requests have been handled.
1059
1060Returns the number of requests processed, but is otherwise strictly
1061equivalent to:
1062
1063 IO::AIO::poll_wait, IO::AIO::poll_cb
1064
850=item IO::AIO::nreqs 1065=item IO::AIO::flush
851 1066
852Returns the number of requests currently in the ready, execute or pending 1067Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1068
855Example: wait till there are no outstanding requests anymore: 1069Strictly equivalent to:
856 1070
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1071 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1072 while IO::AIO::nreqs;
859 1073
860=item IO::AIO::nready 1074=head3 CONTROLLING THE NUMBER OF THREADS
861
862Returns the number of requests currently in the ready state (not yet
863executed).
864
865=item IO::AIO::npending
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 1075
888=item IO::AIO::min_parallel $nthreads 1076=item IO::AIO::min_parallel $nthreads
889 1077
890Set the minimum number of AIO threads to C<$nthreads>. The current 1078Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1079default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1080concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1081however, is unlimited).
894 1082
895IO::AIO starts threads only on demand, when an AIO request is queued and 1083IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1084no free thread exists. Please note that queueing up a hundred requests can
1085create demand for a hundred threads, even if it turns out that everything
1086is in the cache and could have been processed faster by a single thread.
897 1087
898It is recommended to keep the number of threads relatively low, as some 1088It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1089Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1090(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1091versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1105This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1106that all threads are killed and that there are no outstanding requests.
917 1107
918Under normal circumstances you don't need to call this function. 1108Under normal circumstances you don't need to call this function.
919 1109
1110=item IO::AIO::max_idle $nthreads
1111
1112Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1113threads that did not get a request to process within 10 seconds). That
1114means if a thread becomes idle while C<$nthreads> other threads are also
1115idle, it will free its resources and exit.
1116
1117This is useful when you allow a large number of threads (e.g. 100 or 1000)
1118to allow for extremely high load situations, but want to free resources
1119under normal circumstances (1000 threads can easily consume 30MB of RAM).
1120
1121The default is probably ok in most situations, especially if thread
1122creation is fast. If thread creation is very slow on your system you might
1123want to use larger values.
1124
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1125=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
921 1126
922This is a very bad function to use in interactive programs because it 1127This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1128blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1129use an C<aio_group> together with a feed callback.
… …
933 1138
934You can still queue as many requests as you want. Therefore, 1139You can still queue as many requests as you want. Therefore,
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1140C<max_oustsanding> is mainly useful in simple scripts (with low values) or
936as a stop gap to shield against fatal memory overflow (with large values). 1141as a stop gap to shield against fatal memory overflow (with large values).
937 1142
1143=head3 STATISTICAL INFORMATION
1144
1145=item IO::AIO::nreqs
1146
1147Returns the number of requests currently in the ready, execute or pending
1148states (i.e. for which their callback has not been invoked yet).
1149
1150Example: wait till there are no outstanding requests anymore:
1151
1152 IO::AIO::poll_wait, IO::AIO::poll_cb
1153 while IO::AIO::nreqs;
1154
1155=item IO::AIO::nready
1156
1157Returns the number of requests currently in the ready state (not yet
1158executed).
1159
1160=item IO::AIO::npending
1161
1162Returns the number of requests currently in the pending state (executed,
1163but not yet processed by poll_cb).
1164
938=back 1165=back
939 1166
940=cut 1167=cut
941 1168
942# support function to convert a fd into a perl filehandle 1169# support function to convert a fd into a perl filehandle
… …
954 1181
955 *$sym 1182 *$sym
956} 1183}
957 1184
958min_parallel 8; 1185min_parallel 8;
1186
1187END { flush }
959 1188
9601; 11891;
961 1190
962=head2 FORK BEHAVIOUR 1191=head2 FORK BEHAVIOUR
963 1192

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