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Revision 1.80 by root, Thu Oct 26 16:28:33 2006 UTC vs.
Revision 1.100 by root, Sun Jan 7 21:36:58 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
… …
443recurse into (everything else, including symlinks to directories). 590recurse into (everything else, including symlinks to directories).
444 591
445C<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_
446C<$maxreq> specifies the maximum number of outstanding aio requests that 593C<$maxreq> specifies the maximum number of outstanding aio requests that
447this function generates. If it is C<< <= 0 >>, then a suitable default 594this function generates. If it is C<< <= 0 >>, then a suitable default
448will be chosen (currently 6). 595will be chosen (currently 4).
449 596
450On error, the callback is called without arguments, otherwise it receives 597On error, the callback is called without arguments, otherwise it receives
451two array-refs with path-relative entry names. 598two array-refs with path-relative entry names.
452 599
453Example: 600Example:
… …
487as those tend to return 0 or 1 as link counts, which disables the 634as those tend to return 0 or 1 as link counts, which disables the
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 = 6 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<$path>, return the
730status of the final C<rmdir> only. This is a composite request that
731uses C<aio_scandir> to recurse into and rmdir directories, and unlink
732everything else.
733
734=cut
735
736sub aio_rmtree;
737sub aio_rmtree($;$) {
738 aio_block {
739 my ($path, $cb) = @_;
740
741 my $pri = aioreq_pri;
742 my $grp = aio_group $cb;
743
744 aioreq_pri $pri;
745 add $grp aio_scandir $path, 0, sub {
746 my ($dirs, $nondirs) = @_;
747
748 my $dirgrp = aio_group sub {
749 add $grp aio_rmdir $path, sub {
750 $grp->result ($_[0]);
751 };
752 };
753
754 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
755 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
756
757 add $grp $dirgrp;
758 };
759
575 $grp 760 $grp
761 }
576} 762}
577 763
578=item aio_fsync $fh, $callback->($status) 764=item aio_fsync $fh, $callback->($status)
579 765
580Asynchronously call fsync on the given filehandle and call the callback 766Asynchronously call fsync on the given filehandle and call the callback
… …
794 980
795=back 981=back
796 982
797=head2 SUPPORT FUNCTIONS 983=head2 SUPPORT FUNCTIONS
798 984
985=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
986
799=over 4 987=over 4
800 988
801=item $fileno = IO::AIO::poll_fileno 989=item $fileno = IO::AIO::poll_fileno
802 990
803Return the I<request result pipe file descriptor>. This filehandle must be 991Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 995
808See C<poll_cb> for an example. 996See C<poll_cb> for an example.
809 997
810=item IO::AIO::poll_cb 998=item IO::AIO::poll_cb
811 999
812Process all outstanding events on the result pipe. You have to call this 1000Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1001regularly. Returns the number of events processed. Returns immediately
814when no events are outstanding. 1002when no events are outstanding. The amount of events processed depends on
1003the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1004
816If not all requests were processed for whatever reason, the filehandle 1005If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1006will still be ready when C<poll_cb> returns.
818 1007
819Example: Install an Event watcher that automatically calls 1008Example: Install an Event watcher that automatically calls
… …
821 1010
822 Event->io (fd => IO::AIO::poll_fileno, 1011 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1012 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1013 cb => \&IO::AIO::poll_cb);
825 1014
826=item IO::AIO::poll_some $max_requests 1015=item IO::AIO::max_poll_reqs $nreqs
827 1016
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1017=item IO::AIO::max_poll_time $seconds
829at a time.
830 1018
831Useful if you want to ensure some level of interactiveness when perl is 1019These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1020that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1021the maximum amount of time (default C<0>, meaning infinity) spent in
1022C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1023of time C<poll_cb> is allowed to use).
1024
1025Setting C<max_poll_time> to a non-zero value creates an overhead of one
1026syscall per request processed, which is not normally a problem unless your
1027callbacks are really really fast or your OS is really really slow (I am
1028not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1029
1030Setting these is useful if you want to ensure some level of
1031interactiveness when perl is not fast enough to process all requests in
1032time.
1033
1034For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1035
834Example: Install an Event watcher that automatically calls 1036Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1037IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1038program get the CPU sometimes even under high AIO load.
837 1039
1040 # try not to spend much more than 0.1s in poll_cb
1041 IO::AIO::max_poll_time 0.1;
1042
1043 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1044 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1045 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1046 cb => &IO::AIO::poll_cb);
841 1047
842=item IO::AIO::poll_wait 1048=item IO::AIO::poll_wait
843 1049
1050If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1051phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1052does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1053synchronously wait for some requests to finish).
847 1054
848See C<nreqs> for an example. 1055See C<nreqs> for an example.
849 1056
1057=item IO::AIO::poll
1058
1059Waits until some requests have been handled.
1060
1061Returns the number of requests processed, but is otherwise strictly
1062equivalent to:
1063
1064 IO::AIO::poll_wait, IO::AIO::poll_cb
1065
850=item IO::AIO::nreqs 1066=item IO::AIO::flush
851 1067
852Returns the number of requests currently in the ready, execute or pending 1068Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1069
855Example: wait till there are no outstanding requests anymore: 1070Strictly equivalent to:
856 1071
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1072 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1073 while IO::AIO::nreqs;
859 1074
860=item IO::AIO::nready 1075=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 1076
888=item IO::AIO::min_parallel $nthreads 1077=item IO::AIO::min_parallel $nthreads
889 1078
890Set the minimum number of AIO threads to C<$nthreads>. The current 1079Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1080default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1081concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1082however, is unlimited).
894 1083
895IO::AIO starts threads only on demand, when an AIO request is queued and 1084IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1085no free thread exists. Please note that queueing up a hundred requests can
1086create demand for a hundred threads, even if it turns out that everything
1087is in the cache and could have been processed faster by a single thread.
897 1088
898It is recommended to keep the number of threads relatively low, as some 1089It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1090Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1091(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1092versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1106This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1107that all threads are killed and that there are no outstanding requests.
917 1108
918Under normal circumstances you don't need to call this function. 1109Under normal circumstances you don't need to call this function.
919 1110
1111=item IO::AIO::max_idle $nthreads
1112
1113Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1114threads that did not get a request to process within 10 seconds). That
1115means if a thread becomes idle while C<$nthreads> other threads are also
1116idle, it will free its resources and exit.
1117
1118This is useful when you allow a large number of threads (e.g. 100 or 1000)
1119to allow for extremely high load situations, but want to free resources
1120under normal circumstances (1000 threads can easily consume 30MB of RAM).
1121
1122The default is probably ok in most situations, especially if thread
1123creation is fast. If thread creation is very slow on your system you might
1124want to use larger values.
1125
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1126=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
921 1127
922This is a very bad function to use in interactive programs because it 1128This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1129blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1130use an C<aio_group> together with a feed callback.
… …
933 1139
934You can still queue as many requests as you want. Therefore, 1140You can still queue as many requests as you want. Therefore,
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1141C<max_oustsanding> is mainly useful in simple scripts (with low values) or
936as a stop gap to shield against fatal memory overflow (with large values). 1142as a stop gap to shield against fatal memory overflow (with large values).
937 1143
1144=head3 STATISTICAL INFORMATION
1145
1146=item IO::AIO::nreqs
1147
1148Returns the number of requests currently in the ready, execute or pending
1149states (i.e. for which their callback has not been invoked yet).
1150
1151Example: wait till there are no outstanding requests anymore:
1152
1153 IO::AIO::poll_wait, IO::AIO::poll_cb
1154 while IO::AIO::nreqs;
1155
1156=item IO::AIO::nready
1157
1158Returns the number of requests currently in the ready state (not yet
1159executed).
1160
1161=item IO::AIO::npending
1162
1163Returns the number of requests currently in the pending state (executed,
1164but not yet processed by poll_cb).
1165
938=back 1166=back
939 1167
940=cut 1168=cut
941 1169
942# support function to convert a fd into a perl filehandle 1170# support function to convert a fd into a perl filehandle
… …
955 *$sym 1183 *$sym
956} 1184}
957 1185
958min_parallel 8; 1186min_parallel 8;
959 1187
960END { 1188END { flush }
961 max_parallel 0;
962}
963 1189
9641; 11901;
965 1191
966=head2 FORK BEHAVIOUR 1192=head2 FORK BEHAVIOUR
967 1193

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