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Revision 1.77 by root, Wed Oct 25 17:57:30 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); 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 aioreq_pri $pri 250=item $prev_pri = aioreq_pri [$pri]
181 251
182Sets the priority for the next aio request. The default priority 252Returns the priority value that would be used for the next request and, if
253C<$pri> is given, sets the priority for the next aio request.
254
183is C<0>, the minimum and maximum priorities are C<-4> and C<4>, 255The default priority is C<0>, the minimum and maximum priorities are C<-4>
184respectively. Requests with higher priority will be serviced first. 256and C<4>, respectively. Requests with higher priority will be serviced
257first.
185 258
186The priority will be reset to C<0> after each call to one of the C<aio_> 259The priority will be reset to C<0> after each call to one of the C<aio_*>
187functions. 260functions.
188 261
189Example: open a file with low priority, then read something from it with 262Example: open a file with low priority, then read something from it with
190higher priority so the read request is serviced before other low priority 263higher priority so the read request is serviced before other low priority
191open requests (potentially spamming the cache): 264open requests (potentially spamming the cache):
… …
201 }; 274 };
202 275
203=item aioreq_nice $pri_adjust 276=item aioreq_nice $pri_adjust
204 277
205Similar 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
206priority, so effects are cumulative. 279priority, so the effect is cumulative.
207 280
208=item aio_open $pathname, $flags, $mode, $callback->($fh) 281=item aio_open $pathname, $flags, $mode, $callback->($fh)
209 282
210Asynchronously 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
211created filehandle for the file. 284created filehandle for the file.
… …
262 aio_read $fh, 7, 15, $buffer, 0, sub { 335 aio_read $fh, 7, 15, $buffer, 0, sub {
263 $_[0] > 0 or die "read error: $!"; 336 $_[0] > 0 or die "read error: $!";
264 print "read $_[0] bytes: <$buffer>\n"; 337 print "read $_[0] bytes: <$buffer>\n";
265 }; 338 };
266 339
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
335=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)
336 341
337Tries 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
338reading 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
339file 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
… …
394=item aio_unlink $pathname, $callback->($status) 399=item aio_unlink $pathname, $callback->($status)
395 400
396Asynchronously unlink (delete) a file and call the callback with the 401Asynchronously unlink (delete) a file and call the callback with the
397result code. 402result code.
398 403
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
399=item aio_link $srcpath, $dstpath, $callback->($status) 414=item aio_link $srcpath, $dstpath, $callback->($status)
400 415
401Asynchronously 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
402the path C<$dstpath> and call the callback with the result code. 417the path C<$dstpath> and call the callback with the result code.
403 418
404=item aio_symlink $srcpath, $dstpath, $callback->($status) 419=item aio_symlink $srcpath, $dstpath, $callback->($status)
405 420
406Asynchronously 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
407the 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.
408 429
409=item aio_rename $srcpath, $dstpath, $callback->($status) 430=item aio_rename $srcpath, $dstpath, $callback->($status)
410 431
411Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 432Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
412rename(2) and call the callback with the result code. 433rename(2) and call the callback with the result code.
… …
422directory (i.e. opendir + readdir + closedir). The entries will not be 443directory (i.e. opendir + readdir + closedir). The entries will not be
423sorted, and will B<NOT> include the C<.> and C<..> entries. 444sorted, and will B<NOT> include the C<.> and C<..> entries.
424 445
425The 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
426with 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($$;$) {
558 aio_block {
559 my ($src, $dst, $cb) = @_;
560
561 my $pri = aioreq_pri;
562 my $grp = aio_group $cb;
563
564 aioreq_pri $pri;
565 add $grp aio_rename $src, $dst, sub {
566 if ($_[0] && $! == EXDEV) {
567 aioreq_pri $pri;
568 add $grp aio_copy $src, $dst, sub {
569 $grp->result ($_[0]);
570
571 if (!$_[0]) {
572 aioreq_pri $pri;
573 add $grp aio_unlink $src;
574 }
575 };
576 } else {
577 $grp->result ($_[0]);
578 }
579 };
580
581 $grp
582 }
583}
427 584
428=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 585=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
429 586
430Scans a directory (similar to C<aio_readdir>) but additionally tries to 587Scans a directory (similar to C<aio_readdir>) but additionally tries to
431efficiently separate the entries of directory C<$path> into two sets of 588efficiently separate the entries of directory C<$path> into two sets of
… …
433recurse into (everything else, including symlinks to directories). 590recurse into (everything else, including symlinks to directories).
434 591
435C<aio_scandir> is a composite request that creates of many sub requests_ 592C<aio_scandir> is a composite request that creates of many sub requests_
436C<$maxreq> specifies the maximum number of outstanding aio requests that 593C<$maxreq> specifies the maximum number of outstanding aio requests that
437this function generates. If it is C<< <= 0 >>, then a suitable default 594this function generates. If it is C<< <= 0 >>, then a suitable default
438will be chosen (currently 6). 595will be chosen (currently 4).
439 596
440On error, the callback is called without arguments, otherwise it receives 597On error, the callback is called without arguments, otherwise it receives
441two array-refs with path-relative entry names. 598two array-refs with path-relative entry names.
442 599
443Example: 600Example:
… …
478directory counting heuristic. 635directory counting heuristic.
479 636
480=cut 637=cut
481 638
482sub aio_scandir($$$) { 639sub aio_scandir($$$) {
640 aio_block {
483 my ($path, $maxreq, $cb) = @_; 641 my ($path, $maxreq, $cb) = @_;
484 642
643 my $pri = aioreq_pri;
644
485 my $grp = aio_group $cb; 645 my $grp = aio_group $cb;
486 646
487 $maxreq = 6 if $maxreq <= 0; 647 $maxreq = 4 if $maxreq <= 0;
488 648
489 # stat once 649 # stat once
650 aioreq_pri $pri;
490 add $grp aio_stat $path, sub { 651 add $grp aio_stat $path, sub {
491 return $grp->result () if $_[0]; 652 return $grp->result () if $_[0];
492 my $now = time; 653 my $now = time;
493 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 654 my $hash1 = join ":", (stat _)[0,1,3,7,9];
494 655
495 # read the directory entries 656 # read the directory entries
657 aioreq_pri $pri;
496 add $grp aio_readdir $path, sub { 658 add $grp aio_readdir $path, sub {
497 my $entries = shift 659 my $entries = shift
498 or return $grp->result (); 660 or return $grp->result ();
499 661
500 # stat the dir another time 662 # stat the dir another time
663 aioreq_pri $pri;
501 add $grp aio_stat $path, sub { 664 add $grp aio_stat $path, sub {
502 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 665 my $hash2 = join ":", (stat _)[0,1,3,7,9];
503 666
504 my $ndirs; 667 my $ndirs;
505 668
506 # take the slow route if anything looks fishy 669 # take the slow route if anything looks fishy
507 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 670 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
508 $ndirs = -1; 671 $ndirs = -1;
509 } else { 672 } else {
510 # if nlink == 2, we are finished 673 # if nlink == 2, we are finished
511 # on non-posix-fs's, we rely on nlink < 2 674 # on non-posix-fs's, we rely on nlink < 2
512 $ndirs = (stat _)[3] - 2 675 $ndirs = (stat _)[3] - 2
513 or return $grp->result ([], $entries); 676 or return $grp->result ([], $entries);
514 } 677 }
515 678
516 # sort into likely dirs and likely nondirs 679 # sort into likely dirs and likely nondirs
517 # dirs == files without ".", short entries first 680 # dirs == files without ".", short entries first
518 $entries = [map $_->[0], 681 $entries = [map $_->[0],
519 sort { $b->[1] cmp $a->[1] } 682 sort { $b->[1] cmp $a->[1] }
520 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 683 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
521 @$entries]; 684 @$entries];
522 685
523 my (@dirs, @nondirs); 686 my (@dirs, @nondirs);
524 687
525 my $statgrp = add $grp aio_group sub { 688 my $statgrp = add $grp aio_group sub {
526 $grp->result (\@dirs, \@nondirs); 689 $grp->result (\@dirs, \@nondirs);
527 }; 690 };
528 691
529 limit $statgrp $maxreq; 692 limit $statgrp $maxreq;
530 feed $statgrp sub { 693 feed $statgrp sub {
531 return unless @$entries; 694 return unless @$entries;
532 my $entry = pop @$entries; 695 my $entry = pop @$entries;
533 696
697 aioreq_pri $pri;
534 add $statgrp aio_stat "$path/$entry/.", sub { 698 add $statgrp aio_stat "$path/$entry/.", sub {
535 if ($_[0] < 0) { 699 if ($_[0] < 0) {
536 push @nondirs, $entry; 700 push @nondirs, $entry;
537 } else { 701 } else {
538 # need to check for real directory 702 # need to check for real directory
703 aioreq_pri $pri;
539 add $statgrp aio_lstat "$path/$entry", sub { 704 add $statgrp aio_lstat "$path/$entry", sub {
540 if (-d _) { 705 if (-d _) {
541 push @dirs, $entry; 706 push @dirs, $entry;
542 707
543 unless (--$ndirs) { 708 unless (--$ndirs) {
544 push @nondirs, @$entries; 709 push @nondirs, @$entries;
545 feed $statgrp; 710 feed $statgrp;
711 }
712 } else {
713 push @nondirs, $entry;
546 } 714 }
547 } else {
548 push @nondirs, $entry;
549 } 715 }
550 } 716 }
551 } 717 };
552 }; 718 };
553 }; 719 };
554 }; 720 };
555 }; 721 };
722
723 $grp
556 }; 724 }
725}
557 726
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
558 $grp 759 $grp
760 }
559} 761}
560 762
561=item aio_fsync $fh, $callback->($status) 763=item aio_fsync $fh, $callback->($status)
562 764
563Asynchronously call fsync on the given filehandle and call the callback 765Asynchronously call fsync on the given filehandle and call the callback
… …
714itself. Useful when you queued a lot of events but got a result early. 916itself. Useful when you queued a lot of events but got a result early.
715 917
716=item $grp->result (...) 918=item $grp->result (...)
717 919
718Set the result value(s) that will be passed to the group callback when all 920Set the result value(s) that will be passed to the group callback when all
719subrequests have finished. By default, no argument will be passed. 921subrequests have finished and set thre groups errno to the current value
922of errno (just like calling C<errno> without an error number). By default,
923no argument will be passed and errno is zero.
924
925=item $grp->errno ([$errno])
926
927Sets the group errno value to C<$errno>, or the current value of errno
928when the argument is missing.
929
930Every aio request has an associated errno value that is restored when
931the callback is invoked. This method lets you change this value from its
932default (0).
933
934Calling C<result> will also set errno, so make sure you either set C<$!>
935before the call to C<result>, or call c<errno> after it.
720 936
721=item feed $grp $callback->($grp) 937=item feed $grp $callback->($grp)
722 938
723Sets a feeder/generator on this group: every group can have an attached 939Sets a feeder/generator on this group: every group can have an attached
724generator that generates requests if idle. The idea behind this is that, 940generator that generates requests if idle. The idea behind this is that,
… …
763 979
764=back 980=back
765 981
766=head2 SUPPORT FUNCTIONS 982=head2 SUPPORT FUNCTIONS
767 983
984=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
985
768=over 4 986=over 4
769 987
770=item $fileno = IO::AIO::poll_fileno 988=item $fileno = IO::AIO::poll_fileno
771 989
772Return the I<request result pipe file descriptor>. This filehandle must be 990Return the I<request result pipe file descriptor>. This filehandle must be
… …
776 994
777See C<poll_cb> for an example. 995See C<poll_cb> for an example.
778 996
779=item IO::AIO::poll_cb 997=item IO::AIO::poll_cb
780 998
781Process 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
782regularly. Returns the number of events processed. Returns immediately 1000regularly. Returns the number of events processed. Returns immediately
783when 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>.
1003
1004If not all requests were processed for whatever reason, the filehandle
1005will still be ready when C<poll_cb> returns.
784 1006
785Example: Install an Event watcher that automatically calls 1007Example: Install an Event watcher that automatically calls
786IO::AIO::poll_cb with high priority: 1008IO::AIO::poll_cb with high priority:
787 1009
788 Event->io (fd => IO::AIO::poll_fileno, 1010 Event->io (fd => IO::AIO::poll_fileno,
789 poll => 'r', async => 1, 1011 poll => 'r', async => 1,
790 cb => \&IO::AIO::poll_cb); 1012 cb => \&IO::AIO::poll_cb);
791 1013
1014=item IO::AIO::max_poll_reqs $nreqs
1015
1016=item IO::AIO::max_poll_time $seconds
1017
1018These set the maximum number of requests (default C<0>, meaning infinity)
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.
1034
1035Example: Install an Event watcher that automatically calls
1036IO::AIO::poll_cb with low priority, to ensure that other parts of the
1037program get the CPU sometimes even under high AIO load.
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
1043 Event->io (fd => IO::AIO::poll_fileno,
1044 poll => 'r', nice => 1,
1045 cb => &IO::AIO::poll_cb);
1046
792=item IO::AIO::poll_wait 1047=item IO::AIO::poll_wait
793 1048
1049If there are any outstanding requests and none of them in the result
794Wait till the result filehandle becomes ready for reading (simply does a 1050phase, wait till the result filehandle becomes ready for reading (simply
795C<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
796for some requests to finish). 1052synchronously wait for some requests to finish).
797 1053
798See C<nreqs> for an example. 1054See C<nreqs> for an example.
799 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
800=item IO::AIO::nreqs 1065=item IO::AIO::flush
801 1066
802Returns the number of requests currently outstanding (i.e. for which their 1067Wait till all outstanding AIO requests have been handled.
803callback has not been invoked yet).
804 1068
805Example: wait till there are no outstanding requests anymore: 1069Strictly equivalent to:
806 1070
807 IO::AIO::poll_wait, IO::AIO::poll_cb 1071 IO::AIO::poll_wait, IO::AIO::poll_cb
808 while IO::AIO::nreqs; 1072 while IO::AIO::nreqs;
809 1073
810=item IO::AIO::flush 1074=head3 CONTROLLING THE NUMBER OF THREADS
811
812Wait till all outstanding AIO requests have been handled.
813
814Strictly equivalent to:
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 1075
828=item IO::AIO::min_parallel $nthreads 1076=item IO::AIO::min_parallel $nthreads
829 1077
830Set the minimum number of AIO threads to C<$nthreads>. The current 1078Set the minimum number of AIO threads to C<$nthreads>. The current
831default is C<8>, which means eight asynchronous operations can execute 1079default is C<8>, which means eight asynchronous operations can execute
832concurrently at any one time (the number of outstanding requests, 1080concurrently at any one time (the number of outstanding requests,
833however, is unlimited). 1081however, is unlimited).
834 1082
835IO::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
836no 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.
837 1087
838It 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
839Linux kernel versions will scale negatively with the number of threads 1089Linux kernel versions will scale negatively with the number of threads
840(higher parallelity => MUCH higher latency). With current Linux 2.6 1090(higher parallelity => MUCH higher latency). With current Linux 2.6
841versions, 4-32 threads should be fine. 1091versions, 4-32 threads should be fine.
… …
855This 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
856that all threads are killed and that there are no outstanding requests. 1106that all threads are killed and that there are no outstanding requests.
857 1107
858Under normal circumstances you don't need to call this function. 1108Under normal circumstances you don't need to call this function.
859 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
860=item $oldnreqs = IO::AIO::max_outstanding $nreqs 1125=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
861 1126
862[REMOVED] 1127This is a very bad function to use in interactive programs because it
1128blocks, and a bad way to reduce concurrency because it is inexact: Better
1129use an C<aio_group> together with a feed callback.
863 1130
864Pre-2.x versions used max_outstanding for a crude request queue length limit.
865
866In 2.x+ you are advised to use a group and a feeder to limit
867concurrency. The max_outstanding feature ran very unstable (endless
868recursions causing segfaults, bad interaction with groups etc.) and was
869removed.
870
871I am deeply sorry, but I am still on the hunt for a good limiting interface.
872
873Original description was as follows:
874
875Sets the maximum number of outstanding requests to C<$nreqs>. If you try 1131Sets the maximum number of outstanding requests to C<$nreqs>. If you
876to queue up more than this number of requests, the caller will block until 1132to queue up more than this number of requests, the next call to the
877some requests have been handled. 1133C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1134function will block until the limit is no longer exceeded.
1135
1136The default value is very large, so there is no practical limit on the
1137number of outstanding requests.
1138
1139You can still queue as many requests as you want. Therefore,
1140C<max_oustsanding> is mainly useful in simple scripts (with low values) or
1141as a stop gap to shield against fatal memory overflow (with large values).
1142
1143=head3 STATISTICAL INFORMATION
1144
1145=item IO::AIO::nreqs
1146
1147Returns the number of requests currently in the ready, execute or pending
1148states (i.e. for which their callback has not been invoked yet).
1149
1150Example: wait till there are no outstanding requests anymore:
1151
1152 IO::AIO::poll_wait, IO::AIO::poll_cb
1153 while IO::AIO::nreqs;
1154
1155=item IO::AIO::nready
1156
1157Returns the number of requests currently in the ready state (not yet
1158executed).
1159
1160=item IO::AIO::npending
1161
1162Returns the number of requests currently in the pending state (executed,
1163but not yet processed by poll_cb).
878 1164
879=back 1165=back
880 1166
881=cut 1167=cut
882 1168
… …
896 *$sym 1182 *$sym
897} 1183}
898 1184
899min_parallel 8; 1185min_parallel 8;
900 1186
901END { 1187END { flush }
902 max_parallel 0;
903}
904 1188
9051; 11891;
906 1190
907=head2 FORK BEHAVIOUR 1191=head2 FORK BEHAVIOUR
908 1192

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