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Revision 1.75 by root, Tue Oct 24 20:10:26 2006 UTC vs.
Revision 1.105 by root, Sun Mar 25 00:20:27 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 = '2.33';
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 aio_mkdir);
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 max_outstanding 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.
… …
217list. They are the same as used by C<sysopen>. 290list. They are the same as used by C<sysopen>.
218 291
219Likewise, C<$mode> specifies the mode of the newly created file, if it 292Likewise, C<$mode> specifies the mode of the newly created file, if it
220didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 293didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
221except that it is mandatory (i.e. use C<0> if you don't create new files, 294except that it is mandatory (i.e. use C<0> if you don't create new files,
222and C<0666> or C<0777> if you do). 295and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
296by the umask in effect then the request is being executed, so better never
297change the umask.
223 298
224Example: 299Example:
225 300
226 aio_open "/etc/passwd", O_RDONLY, 0, sub { 301 aio_open "/etc/passwd", O_RDONLY, 0, sub {
227 if ($_[0]) { 302 if ($_[0]) {
… …
262 aio_read $fh, 7, 15, $buffer, 0, sub { 337 aio_read $fh, 7, 15, $buffer, 0, sub {
263 $_[0] > 0 or die "read error: $!"; 338 $_[0] > 0 or die "read error: $!";
264 print "read $_[0] bytes: <$buffer>\n"; 339 print "read $_[0] bytes: <$buffer>\n";
265 }; 340 };
266 341
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) 342=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
336 343
337Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 344Tries 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 345reading 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 346file offset of C<$out_fh>. Because of that, it is not safe to issue more
… …
394=item aio_unlink $pathname, $callback->($status) 401=item aio_unlink $pathname, $callback->($status)
395 402
396Asynchronously unlink (delete) a file and call the callback with the 403Asynchronously unlink (delete) a file and call the callback with the
397result code. 404result code.
398 405
406=item aio_mknod $path, $mode, $dev, $callback->($status)
407
408[EXPERIMENTAL]
409
410Asynchronously create a device node (or fifo). See mknod(2).
411
412The only (POSIX-) portable way of calling this function is:
413
414 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
415
399=item aio_link $srcpath, $dstpath, $callback->($status) 416=item aio_link $srcpath, $dstpath, $callback->($status)
400 417
401Asynchronously create a new link to the existing object at C<$srcpath> at 418Asynchronously create a new link to the existing object at C<$srcpath> at
402the path C<$dstpath> and call the callback with the result code. 419the path C<$dstpath> and call the callback with the result code.
403 420
404=item aio_symlink $srcpath, $dstpath, $callback->($status) 421=item aio_symlink $srcpath, $dstpath, $callback->($status)
405 422
406Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 423Asynchronously 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. 424the path C<$dstpath> and call the callback with the result code.
408 425
426=item aio_readlink $path, $callback->($link)
427
428Asynchronously read the symlink specified by C<$path> and pass it to
429the callback. If an error occurs, nothing or undef gets passed to the
430callback.
431
409=item aio_rename $srcpath, $dstpath, $callback->($status) 432=item aio_rename $srcpath, $dstpath, $callback->($status)
410 433
411Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 434Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
412rename(2) and call the callback with the result code. 435rename(2) and call the callback with the result code.
436
437=item aio_mkdir $pathname, $mode, $callback->($status)
438
439Asynchronously mkdir (create) a directory and call the callback with
440the result code. C<$mode> will be modified by the umask at the time the
441request is executed, so do not change your umask.
413 442
414=item aio_rmdir $pathname, $callback->($status) 443=item aio_rmdir $pathname, $callback->($status)
415 444
416Asynchronously rmdir (delete) a directory and call the callback with the 445Asynchronously rmdir (delete) a directory and call the callback with the
417result code. 446result code.
… …
423sorted, and will B<NOT> include the C<.> and C<..> entries. 452sorted, and will B<NOT> include the C<.> and C<..> entries.
424 453
425The callback a single argument which is either C<undef> or an array-ref 454The callback a single argument which is either C<undef> or an array-ref
426with the filenames. 455with the filenames.
427 456
457=item aio_load $path, $data, $callback->($status)
458
459This is a composite request that tries to fully load the given file into
460memory. Status is the same as with aio_read.
461
462=cut
463
464sub aio_load($$;$) {
465 aio_block {
466 my ($path, undef, $cb) = @_;
467 my $data = \$_[1];
468
469 my $pri = aioreq_pri;
470 my $grp = aio_group $cb;
471
472 aioreq_pri $pri;
473 add $grp aio_open $path, O_RDONLY, 0, sub {
474 my $fh = shift
475 or return $grp->result (-1);
476
477 aioreq_pri $pri;
478 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
479 $grp->result ($_[0]);
480 };
481 };
482
483 $grp
484 }
485}
486
487=item aio_copy $srcpath, $dstpath, $callback->($status)
488
489Try to copy the I<file> (directories not supported as either source or
490destination) from C<$srcpath> to C<$dstpath> and call the callback with
491the C<0> (error) or C<-1> ok.
492
493This is a composite request that it creates the destination file with
494mode 0200 and copies the contents of the source file into it using
495C<aio_sendfile>, followed by restoring atime, mtime, access mode and
496uid/gid, in that order.
497
498If an error occurs, the partial destination file will be unlinked, if
499possible, except when setting atime, mtime, access mode and uid/gid, where
500errors are being ignored.
501
502=cut
503
504sub aio_copy($$;$) {
505 aio_block {
506 my ($src, $dst, $cb) = @_;
507
508 my $pri = aioreq_pri;
509 my $grp = aio_group $cb;
510
511 aioreq_pri $pri;
512 add $grp aio_open $src, O_RDONLY, 0, sub {
513 if (my $src_fh = $_[0]) {
514 my @stat = stat $src_fh;
515
516 aioreq_pri $pri;
517 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
518 if (my $dst_fh = $_[0]) {
519 aioreq_pri $pri;
520 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
521 if ($_[0] == $stat[7]) {
522 $grp->result (0);
523 close $src_fh;
524
525 # those should not normally block. should. should.
526 utime $stat[8], $stat[9], $dst;
527 chmod $stat[2] & 07777, $dst_fh;
528 chown $stat[4], $stat[5], $dst_fh;
529 close $dst_fh;
530 } else {
531 $grp->result (-1);
532 close $src_fh;
533 close $dst_fh;
534
535 aioreq $pri;
536 add $grp aio_unlink $dst;
537 }
538 };
539 } else {
540 $grp->result (-1);
541 }
542 },
543
544 } else {
545 $grp->result (-1);
546 }
547 };
548
549 $grp
550 }
551}
552
553=item aio_move $srcpath, $dstpath, $callback->($status)
554
555Try to move the I<file> (directories not supported as either source or
556destination) from C<$srcpath> to C<$dstpath> and call the callback with
557the C<0> (error) or C<-1> ok.
558
559This is a composite request that tries to rename(2) the file first. If
560rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
561that is successful, unlinking the C<$srcpath>.
562
563=cut
564
565sub aio_move($$;$) {
566 aio_block {
567 my ($src, $dst, $cb) = @_;
568
569 my $pri = aioreq_pri;
570 my $grp = aio_group $cb;
571
572 aioreq_pri $pri;
573 add $grp aio_rename $src, $dst, sub {
574 if ($_[0] && $! == EXDEV) {
575 aioreq_pri $pri;
576 add $grp aio_copy $src, $dst, sub {
577 $grp->result ($_[0]);
578
579 if (!$_[0]) {
580 aioreq_pri $pri;
581 add $grp aio_unlink $src;
582 }
583 };
584 } else {
585 $grp->result ($_[0]);
586 }
587 };
588
589 $grp
590 }
591}
592
428=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 593=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
429 594
430Scans a directory (similar to C<aio_readdir>) but additionally tries to 595Scans a directory (similar to C<aio_readdir>) but additionally tries to
431separate the entries of directory C<$path> into two sets of names, ones 596efficiently separate the entries of directory C<$path> into two sets of
432you can recurse into (directories or links to them), and ones you cannot 597names, directories you can recurse into (directories), and ones you cannot
433recurse into (everything else). 598recurse into (everything else, including symlinks to directories).
434 599
435C<aio_scandir> is a composite request that creates of many sub requests_ 600C<aio_scandir> is a composite request that creates of many sub requests_
436C<$maxreq> specifies the maximum number of outstanding aio requests that 601C<$maxreq> specifies the maximum number of outstanding aio requests that
437this function generates. If it is C<< <= 0 >>, then a suitable default 602this function generates. If it is C<< <= 0 >>, then a suitable default
438will be chosen (currently 6). 603will be chosen (currently 4).
439 604
440On error, the callback is called without arguments, otherwise it receives 605On error, the callback is called without arguments, otherwise it receives
441two array-refs with path-relative entry names. 606two array-refs with path-relative entry names.
442 607
443Example: 608Example:
… …
477as those tend to return 0 or 1 as link counts, which disables the 642as those tend to return 0 or 1 as link counts, which disables the
478directory counting heuristic. 643directory counting heuristic.
479 644
480=cut 645=cut
481 646
482sub aio_scandir($$$) { 647sub aio_scandir($$;$) {
648 aio_block {
483 my ($path, $maxreq, $cb) = @_; 649 my ($path, $maxreq, $cb) = @_;
484 650
651 my $pri = aioreq_pri;
652
485 my $grp = aio_group $cb; 653 my $grp = aio_group $cb;
486 654
487 $maxreq = 6 if $maxreq <= 0; 655 $maxreq = 4 if $maxreq <= 0;
488 656
489 # stat once 657 # stat once
658 aioreq_pri $pri;
490 add $grp aio_stat $path, sub { 659 add $grp aio_stat $path, sub {
491 return $grp->result () if $_[0]; 660 return $grp->result () if $_[0];
492 my $now = time; 661 my $now = time;
493 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 662 my $hash1 = join ":", (stat _)[0,1,3,7,9];
494 663
495 # read the directory entries 664 # read the directory entries
665 aioreq_pri $pri;
496 add $grp aio_readdir $path, sub { 666 add $grp aio_readdir $path, sub {
497 my $entries = shift 667 my $entries = shift
498 or return $grp->result (); 668 or return $grp->result ();
499 669
500 # stat the dir another time 670 # stat the dir another time
671 aioreq_pri $pri;
501 add $grp aio_stat $path, sub { 672 add $grp aio_stat $path, sub {
502 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 673 my $hash2 = join ":", (stat _)[0,1,3,7,9];
503 674
504 my $ndirs; 675 my $ndirs;
505 676
506 # take the slow route if anything looks fishy 677 # take the slow route if anything looks fishy
507 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 678 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
508 $ndirs = -1; 679 $ndirs = -1;
509 } else { 680 } else {
510 # if nlink == 2, we are finished 681 # if nlink == 2, we are finished
511 # on non-posix-fs's, we rely on nlink < 2 682 # on non-posix-fs's, we rely on nlink < 2
512 $ndirs = (stat _)[3] - 2 683 $ndirs = (stat _)[3] - 2
513 or return $grp->result ([], $entries); 684 or return $grp->result ([], $entries);
514 } 685 }
515 686
516 # sort into likely dirs and likely nondirs 687 # sort into likely dirs and likely nondirs
517 # dirs == files without ".", short entries first 688 # dirs == files without ".", short entries first
518 $entries = [map $_->[0], 689 $entries = [map $_->[0],
519 sort { $b->[1] cmp $a->[1] } 690 sort { $b->[1] cmp $a->[1] }
520 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 691 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
521 @$entries]; 692 @$entries];
522 693
523 my (@dirs, @nondirs); 694 my (@dirs, @nondirs);
524 695
525 my $statgrp = add $grp aio_group sub { 696 my $statgrp = add $grp aio_group sub {
526 $grp->result (\@dirs, \@nondirs); 697 $grp->result (\@dirs, \@nondirs);
527 }; 698 };
528 699
529 limit $statgrp $maxreq; 700 limit $statgrp $maxreq;
530 feed $statgrp sub { 701 feed $statgrp sub {
531 return unless @$entries; 702 return unless @$entries;
532 my $entry = pop @$entries; 703 my $entry = pop @$entries;
533 704
705 aioreq_pri $pri;
534 add $statgrp aio_stat "$path/$entry/.", sub { 706 add $statgrp aio_stat "$path/$entry/.", sub {
535 if ($_[0] < 0) { 707 if ($_[0] < 0) {
536 push @nondirs, $entry; 708 push @nondirs, $entry;
537 } else { 709 } else {
538 # need to check for real directory 710 # need to check for real directory
711 aioreq_pri $pri;
539 add $statgrp aio_lstat "$path/$entry", sub { 712 add $statgrp aio_lstat "$path/$entry", sub {
540 if (-d _) { 713 if (-d _) {
541 push @dirs, $entry; 714 push @dirs, $entry;
542 715
543 unless (--$ndirs) { 716 unless (--$ndirs) {
544 push @nondirs, @$entries; 717 push @nondirs, @$entries;
545 feed $statgrp; 718 feed $statgrp;
719 }
720 } else {
721 push @nondirs, $entry;
546 } 722 }
547 } else {
548 push @nondirs, $entry;
549 } 723 }
550 } 724 }
551 } 725 };
552 }; 726 };
553 }; 727 };
554 }; 728 };
555 }; 729 };
730
731 $grp
556 }; 732 }
733}
557 734
735=item aio_rmtree $path, $callback->($status)
736
737Delete a directory tree starting (and including) C<$path>, return the
738status of the final C<rmdir> only. This is a composite request that
739uses C<aio_scandir> to recurse into and rmdir directories, and unlink
740everything else.
741
742=cut
743
744sub aio_rmtree;
745sub aio_rmtree($;$) {
746 aio_block {
747 my ($path, $cb) = @_;
748
749 my $pri = aioreq_pri;
750 my $grp = aio_group $cb;
751
752 aioreq_pri $pri;
753 add $grp aio_scandir $path, 0, sub {
754 my ($dirs, $nondirs) = @_;
755
756 my $dirgrp = aio_group sub {
757 add $grp aio_rmdir $path, sub {
758 $grp->result ($_[0]);
759 };
760 };
761
762 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
763 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
764
765 add $grp $dirgrp;
766 };
767
558 $grp 768 $grp
769 }
559} 770}
560 771
561=item aio_fsync $fh, $callback->($status) 772=item aio_fsync $fh, $callback->($status)
562 773
563Asynchronously call fsync on the given filehandle and call the callback 774Asynchronously call fsync on the given filehandle and call the callback
… …
682=item * They can also can also be added to other IO::AIO::GRP objects. 893=item * They can also can also be added to other IO::AIO::GRP objects.
683 894
684=item * You must not add requests to a group from within the group callback (or 895=item * You must not add requests to a group from within the group callback (or
685any later time). 896any later time).
686 897
687=item * This does not harmonise well with C<max_outstanding>, so best do
688not combine C<aio_group> with it. Groups and feeders are recommended for
689this kind of concurrency-limiting.
690
691=back 898=back
692 899
693Their lifetime, simplified, looks like this: when they are empty, they 900Their lifetime, simplified, looks like this: when they are empty, they
694will finish very quickly. If they contain only requests that are in the 901will finish very quickly. If they contain only requests that are in the
695C<done> state, they will also finish. Otherwise they will continue to 902C<done> state, they will also finish. Otherwise they will continue to
… …
718itself. Useful when you queued a lot of events but got a result early. 925itself. Useful when you queued a lot of events but got a result early.
719 926
720=item $grp->result (...) 927=item $grp->result (...)
721 928
722Set the result value(s) that will be passed to the group callback when all 929Set the result value(s) that will be passed to the group callback when all
723subrequests have finished. By default, no argument will be passed. 930subrequests have finished and set thre groups errno to the current value
931of errno (just like calling C<errno> without an error number). By default,
932no argument will be passed and errno is zero.
933
934=item $grp->errno ([$errno])
935
936Sets the group errno value to C<$errno>, or the current value of errno
937when the argument is missing.
938
939Every aio request has an associated errno value that is restored when
940the callback is invoked. This method lets you change this value from its
941default (0).
942
943Calling C<result> will also set errno, so make sure you either set C<$!>
944before the call to C<result>, or call c<errno> after it.
724 945
725=item feed $grp $callback->($grp) 946=item feed $grp $callback->($grp)
726 947
727Sets a feeder/generator on this group: every group can have an attached 948Sets a feeder/generator on this group: every group can have an attached
728generator that generates requests if idle. The idea behind this is that, 949generator that generates requests if idle. The idea behind this is that,
… …
767 988
768=back 989=back
769 990
770=head2 SUPPORT FUNCTIONS 991=head2 SUPPORT FUNCTIONS
771 992
993=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
994
772=over 4 995=over 4
773 996
774=item $fileno = IO::AIO::poll_fileno 997=item $fileno = IO::AIO::poll_fileno
775 998
776Return the I<request result pipe file descriptor>. This filehandle must be 999Return the I<request result pipe file descriptor>. This filehandle must be
… …
780 1003
781See C<poll_cb> for an example. 1004See C<poll_cb> for an example.
782 1005
783=item IO::AIO::poll_cb 1006=item IO::AIO::poll_cb
784 1007
785Process all outstanding events on the result pipe. You have to call this 1008Process some outstanding events on the result pipe. You have to call this
786regularly. Returns the number of events processed. Returns immediately 1009regularly. Returns the number of events processed. Returns immediately
787when no events are outstanding. 1010when no events are outstanding. The amount of events processed depends on
1011the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1012
1013If not all requests were processed for whatever reason, the filehandle
1014will still be ready when C<poll_cb> returns.
788 1015
789Example: Install an Event watcher that automatically calls 1016Example: Install an Event watcher that automatically calls
790IO::AIO::poll_cb with high priority: 1017IO::AIO::poll_cb with high priority:
791 1018
792 Event->io (fd => IO::AIO::poll_fileno, 1019 Event->io (fd => IO::AIO::poll_fileno,
793 poll => 'r', async => 1, 1020 poll => 'r', async => 1,
794 cb => \&IO::AIO::poll_cb); 1021 cb => \&IO::AIO::poll_cb);
795 1022
1023=item IO::AIO::max_poll_reqs $nreqs
1024
1025=item IO::AIO::max_poll_time $seconds
1026
1027These set the maximum number of requests (default C<0>, meaning infinity)
1028that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1029the maximum amount of time (default C<0>, meaning infinity) spent in
1030C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1031of time C<poll_cb> is allowed to use).
1032
1033Setting C<max_poll_time> to a non-zero value creates an overhead of one
1034syscall per request processed, which is not normally a problem unless your
1035callbacks are really really fast or your OS is really really slow (I am
1036not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1037
1038Setting these is useful if you want to ensure some level of
1039interactiveness when perl is not fast enough to process all requests in
1040time.
1041
1042For interactive programs, values such as C<0.01> to C<0.1> should be fine.
1043
1044Example: Install an Event watcher that automatically calls
1045IO::AIO::poll_cb with low priority, to ensure that other parts of the
1046program get the CPU sometimes even under high AIO load.
1047
1048 # try not to spend much more than 0.1s in poll_cb
1049 IO::AIO::max_poll_time 0.1;
1050
1051 # use a low priority so other tasks have priority
1052 Event->io (fd => IO::AIO::poll_fileno,
1053 poll => 'r', nice => 1,
1054 cb => &IO::AIO::poll_cb);
1055
796=item IO::AIO::poll_wait 1056=item IO::AIO::poll_wait
797 1057
1058If there are any outstanding requests and none of them in the result
798Wait till the result filehandle becomes ready for reading (simply does a 1059phase, wait till the result filehandle becomes ready for reading (simply
799C<select> on the filehandle. This is useful if you want to synchronously wait 1060does a C<select> on the filehandle. This is useful if you want to
800for some requests to finish). 1061synchronously wait for some requests to finish).
801 1062
802See C<nreqs> for an example. 1063See C<nreqs> for an example.
803 1064
1065=item IO::AIO::poll
1066
1067Waits until some requests have been handled.
1068
1069Returns the number of requests processed, but is otherwise strictly
1070equivalent to:
1071
1072 IO::AIO::poll_wait, IO::AIO::poll_cb
1073
804=item IO::AIO::nreqs 1074=item IO::AIO::flush
805 1075
806Returns the number of requests currently outstanding (i.e. for which their 1076Wait till all outstanding AIO requests have been handled.
807callback has not been invoked yet).
808 1077
809Example: wait till there are no outstanding requests anymore: 1078Strictly equivalent to:
810 1079
811 IO::AIO::poll_wait, IO::AIO::poll_cb 1080 IO::AIO::poll_wait, IO::AIO::poll_cb
812 while IO::AIO::nreqs; 1081 while IO::AIO::nreqs;
813 1082
814=item IO::AIO::flush 1083=back
815 1084
816Wait till all outstanding AIO requests have been handled. 1085=head3 CONTROLLING THE NUMBER OF THREADS
817 1086
818Strictly equivalent to: 1087=over
819
820 IO::AIO::poll_wait, IO::AIO::poll_cb
821 while IO::AIO::nreqs;
822
823=item IO::AIO::poll
824
825Waits until some requests have been handled.
826
827Strictly equivalent to:
828
829 IO::AIO::poll_wait, IO::AIO::poll_cb
830 if IO::AIO::nreqs;
831 1088
832=item IO::AIO::min_parallel $nthreads 1089=item IO::AIO::min_parallel $nthreads
833 1090
834Set the minimum number of AIO threads to C<$nthreads>. The current 1091Set the minimum number of AIO threads to C<$nthreads>. The current
835default is C<8>, which means eight asynchronous operations can execute 1092default is C<8>, which means eight asynchronous operations can execute
836concurrently at any one time (the number of outstanding requests, 1093concurrently at any one time (the number of outstanding requests,
837however, is unlimited). 1094however, is unlimited).
838 1095
839IO::AIO starts threads only on demand, when an AIO request is queued and 1096IO::AIO starts threads only on demand, when an AIO request is queued and
840no free thread exists. 1097no free thread exists. Please note that queueing up a hundred requests can
1098create demand for a hundred threads, even if it turns out that everything
1099is in the cache and could have been processed faster by a single thread.
841 1100
842It is recommended to keep the number of threads relatively low, as some 1101It is recommended to keep the number of threads relatively low, as some
843Linux kernel versions will scale negatively with the number of threads 1102Linux kernel versions will scale negatively with the number of threads
844(higher parallelity => MUCH higher latency). With current Linux 2.6 1103(higher parallelity => MUCH higher latency). With current Linux 2.6
845versions, 4-32 threads should be fine. 1104versions, 4-32 threads should be fine.
… …
859This module automatically runs C<max_parallel 0> at program end, to ensure 1118This module automatically runs C<max_parallel 0> at program end, to ensure
860that all threads are killed and that there are no outstanding requests. 1119that all threads are killed and that there are no outstanding requests.
861 1120
862Under normal circumstances you don't need to call this function. 1121Under normal circumstances you don't need to call this function.
863 1122
1123=item IO::AIO::max_idle $nthreads
1124
1125Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1126threads that did not get a request to process within 10 seconds). That
1127means if a thread becomes idle while C<$nthreads> other threads are also
1128idle, it will free its resources and exit.
1129
1130This is useful when you allow a large number of threads (e.g. 100 or 1000)
1131to allow for extremely high load situations, but want to free resources
1132under normal circumstances (1000 threads can easily consume 30MB of RAM).
1133
1134The default is probably ok in most situations, especially if thread
1135creation is fast. If thread creation is very slow on your system you might
1136want to use larger values.
1137
864=item $oldnreqs = IO::AIO::max_outstanding $nreqs 1138=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
865 1139
866[DEPRECATED] 1140This is a very bad function to use in interactive programs because it
1141blocks, and a bad way to reduce concurrency because it is inexact: Better
1142use an C<aio_group> together with a feed callback.
867 1143
868Sets the maximum number of outstanding requests to C<$nreqs>. If you 1144Sets the maximum number of outstanding requests to C<$nreqs>. If you
869try to queue up more than this number of requests, the caller will block until 1145to queue up more than this number of requests, the next call to the
870some requests have been handled. 1146C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1147function will block until the limit is no longer exceeded.
871 1148
872The default is very large, so normally there is no practical limit. If you 1149The default value is very large, so there is no practical limit on the
873queue up many requests in a loop it often improves speed if you set 1150number of outstanding requests.
874this to a relatively low number, such as C<100>.
875 1151
876This function does not work well together with C<aio_group>'s, and their 1152You can still queue as many requests as you want. Therefore,
877feeder interface is better suited to limiting concurrency, so do not use 1153C<max_oustsanding> is mainly useful in simple scripts (with low values) or
878this function. 1154as a stop gap to shield against fatal memory overflow (with large values).
879 1155
880Under normal circumstances you don't need to call this function. 1156=back
1157
1158=head3 STATISTICAL INFORMATION
1159
1160=over
1161
1162=item IO::AIO::nreqs
1163
1164Returns the number of requests currently in the ready, execute or pending
1165states (i.e. for which their callback has not been invoked yet).
1166
1167Example: wait till there are no outstanding requests anymore:
1168
1169 IO::AIO::poll_wait, IO::AIO::poll_cb
1170 while IO::AIO::nreqs;
1171
1172=item IO::AIO::nready
1173
1174Returns the number of requests currently in the ready state (not yet
1175executed).
1176
1177=item IO::AIO::npending
1178
1179Returns the number of requests currently in the pending state (executed,
1180but not yet processed by poll_cb).
881 1181
882=back 1182=back
883 1183
884=cut 1184=cut
885 1185
… …
899 *$sym 1199 *$sym
900} 1200}
901 1201
902min_parallel 8; 1202min_parallel 8;
903 1203
904END { 1204END { flush }
905 max_parallel 0;
906}
907 1205
9081; 12061;
909 1207
910=head2 FORK BEHAVIOUR 1208=head2 FORK BEHAVIOUR
911 1209

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