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Revision 1.83 by root, Fri Oct 27 20:11:58 2006 UTC vs.
Revision 1.106 by root, Fri Jun 1 05:51:21 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 = '2.4';
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
200 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
136 aio_copy aio_group aio_nop aio_mknod); 201 aio_chown aio_chmod aio_utime);
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 202 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 203 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 204 min_parallel max_parallel max_idle
205 nreqs nready npending nthreads
206 max_poll_time max_poll_reqs);
140 207
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 208 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 209
143 require XSLoader; 210 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 211 XSLoader::load ("IO::AIO", $VERSION);
145} 212}
146 213
147=head1 FUNCTIONS 214=head1 FUNCTIONS
148 215
149=head2 AIO FUNCTIONS 216=head2 AIO REQUEST FUNCTIONS
150 217
151All the C<aio_*> calls are more or less thin wrappers around the syscall 218All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 219with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 220and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 221which must be a code reference. This code reference will get called with
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157syscall has been executed asynchronously. 224syscall has been executed asynchronously.
158 225
159All functions expecting a filehandle keep a copy of the filehandle 226All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 227internally until the request has finished.
161 228
162All requests return objects of type L<IO::AIO::REQ> that allow further 229All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 230further manipulation of those requests while they are in-flight.
164 231
165The pathnames you pass to these routines I<must> be absolute and 232The 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 233encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 234request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 235changed. Alternatively, you can make sure that you never change the
169current working directory. 236current working directory anywhere in the program and then use relative
237paths.
170 238
171To encode pathnames to byte form, either make sure you either: a) 239To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 240in 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 241tinkering, 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 242your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 243environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 244use something else to ensure your scalar has the correct contents.
245
246This works, btw. independent of the internal UTF-8 bit, which IO::AIO
247handles correctly wether it is set or not.
177 248
178=over 4 249=over 4
179 250
180=item $prev_pri = aioreq_pri [$pri] 251=item $prev_pri = aioreq_pri [$pri]
181 252
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201 aio_read $_[0], ..., sub { 272 aio_read $_[0], ..., sub {
202 ... 273 ...
203 }; 274 };
204 }; 275 };
205 276
277
206=item aioreq_nice $pri_adjust 278=item aioreq_nice $pri_adjust
207 279
208Similar to C<aioreq_pri>, but subtracts the given value from the current 280Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 281priority, so the effect is cumulative.
282
210 283
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 284=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 285
213Asynchronously open or create a file and call the callback with a newly 286Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 287created filehandle for the file.
… …
220list. They are the same as used by C<sysopen>. 293list. They are the same as used by C<sysopen>.
221 294
222Likewise, C<$mode> specifies the mode of the newly created file, if it 295Likewise, C<$mode> specifies the mode of the newly created file, if it
223didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 296didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224except that it is mandatory (i.e. use C<0> if you don't create new files, 297except that it is mandatory (i.e. use C<0> if you don't create new files,
225and C<0666> or C<0777> if you do). 298and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
299by the umask in effect then the request is being executed, so better never
300change the umask.
226 301
227Example: 302Example:
228 303
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 304 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 305 if ($_[0]) {
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233 } else { 308 } else {
234 die "open failed: $!\n"; 309 die "open failed: $!\n";
235 } 310 }
236 }; 311 };
237 312
313
238=item aio_close $fh, $callback->($status) 314=item aio_close $fh, $callback->($status)
239 315
240Asynchronously close a file and call the callback with the result 316Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 317code. I<WARNING:> although accepted, you should not pass in a perl
242filehandle here, as perl will likely close the file descriptor another 318filehandle here, as perl will likely close the file descriptor another
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244C<close> or just let filehandles go out of scope. 320C<close> or just let filehandles go out of scope.
245 321
246This is supposed to be a bug in the API, so that might change. It's 322This is supposed to be a bug in the API, so that might change. It's
247therefore best to avoid this function. 323therefore best to avoid this function.
248 324
325
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 326=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 327
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 328=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 329
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 330Reads or writes C<length> bytes from the specified C<fh> and C<offset>
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264 341
265 aio_read $fh, 7, 15, $buffer, 0, sub { 342 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 343 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 344 print "read $_[0] bytes: <$buffer>\n";
268 }; 345 };
346
269 347
270=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 348=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
271 349
272Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 350Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
273reading at byte offset C<$in_offset>, and starts writing at the current 351reading at byte offset C<$in_offset>, and starts writing at the current
… …
287C<$in_fh> than are written, and there is no way to find out how many 365C<$in_fh> than are written, and there is no way to find out how many
288bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 366bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
289provides the number of bytes written to C<$out_fh>. Only if the result 367provides the number of bytes written to C<$out_fh>. Only if the result
290value equals C<$length> one can assume that C<$length> bytes have been 368value equals C<$length> one can assume that C<$length> bytes have been
291read. 369read.
370
292 371
293=item aio_readahead $fh,$offset,$length, $callback->($retval) 372=item aio_readahead $fh,$offset,$length, $callback->($retval)
294 373
295C<aio_readahead> populates the page cache with data from a file so that 374C<aio_readahead> populates the page cache with data from a file so that
296subsequent reads from that file will not block on disk I/O. The C<$offset> 375subsequent reads from that file will not block on disk I/O. The C<$offset>
… …
302file. The current file offset of the file is left unchanged. 381file. The current file offset of the file is left unchanged.
303 382
304If that syscall doesn't exist (likely if your OS isn't Linux) it will be 383If that syscall doesn't exist (likely if your OS isn't Linux) it will be
305emulated by simply reading the data, which would have a similar effect. 384emulated by simply reading the data, which would have a similar effect.
306 385
386
307=item aio_stat $fh_or_path, $callback->($status) 387=item aio_stat $fh_or_path, $callback->($status)
308 388
309=item aio_lstat $fh, $callback->($status) 389=item aio_lstat $fh, $callback->($status)
310 390
311Works like perl's C<stat> or C<lstat> in void context. The callback will 391Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
324 aio_stat "/etc/passwd", sub { 404 aio_stat "/etc/passwd", sub {
325 $_[0] and die "stat failed: $!"; 405 $_[0] and die "stat failed: $!";
326 print "size is ", -s _, "\n"; 406 print "size is ", -s _, "\n";
327 }; 407 };
328 408
409
410=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
411
412Works like perl's C<utime> function (including the special case of $atime
413and $mtime being undef). Fractional times are supported if the underlying
414syscalls support them.
415
416When called with a pathname, uses utimes(2) if available, otherwise
417utime(2). If called on a file descriptor, uses futimes(2) if available,
418otherwise returns ENOSYS, so this is not portable.
419
420Examples:
421
422 # set atime and mtime to current time:
423 aio_utime "path", undef, undef;
424 # set atime to current time and mtime to beginning of the epoch:
425 aio_utime "path", time, undef; # undef==0
426
427
428=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
429
430Works like perl's C<chown> function, except that C<undef> for either $uid
431or $gid is being interpreted as "do not change" (but -1 can also be used).
432
433Examples:
434
435 # same as "chown root path" in the shell:
436 aio_chown "path", 0, -1;
437 # same as above:
438 aio_chown "path", 0, undef;
439
440
441=item aio_chmod $fh_or_path, $mode, $callback->($status)
442
443Works like perl's C<chmod> function.
444
445
329=item aio_unlink $pathname, $callback->($status) 446=item aio_unlink $pathname, $callback->($status)
330 447
331Asynchronously unlink (delete) a file and call the callback with the 448Asynchronously unlink (delete) a file and call the callback with the
332result code. 449result code.
333 450
451
334=item aio_mknod $path, $mode, $dev, $callback->($status) 452=item aio_mknod $path, $mode, $dev, $callback->($status)
335 453
454[EXPERIMENTAL]
455
336Asynchronously create a device node (or fifo). See mknod(2). 456Asynchronously create a device node (or fifo). See mknod(2).
337 457
338The only portable (POSIX) way of calling this function is: 458The only (POSIX-) portable way of calling this function is:
339 459
340 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 460 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
461
341 462
342=item aio_link $srcpath, $dstpath, $callback->($status) 463=item aio_link $srcpath, $dstpath, $callback->($status)
343 464
344Asynchronously create a new link to the existing object at C<$srcpath> at 465Asynchronously create a new link to the existing object at C<$srcpath> at
345the path C<$dstpath> and call the callback with the result code. 466the path C<$dstpath> and call the callback with the result code.
346 467
468
347=item aio_symlink $srcpath, $dstpath, $callback->($status) 469=item aio_symlink $srcpath, $dstpath, $callback->($status)
348 470
349Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 471Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
350the path C<$dstpath> and call the callback with the result code. 472the path C<$dstpath> and call the callback with the result code.
351 473
474
475=item aio_readlink $path, $callback->($link)
476
477Asynchronously read the symlink specified by C<$path> and pass it to
478the callback. If an error occurs, nothing or undef gets passed to the
479callback.
480
481
352=item aio_rename $srcpath, $dstpath, $callback->($status) 482=item aio_rename $srcpath, $dstpath, $callback->($status)
353 483
354Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 484Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
355rename(2) and call the callback with the result code. 485rename(2) and call the callback with the result code.
356 486
487
488=item aio_mkdir $pathname, $mode, $callback->($status)
489
490Asynchronously mkdir (create) a directory and call the callback with
491the result code. C<$mode> will be modified by the umask at the time the
492request is executed, so do not change your umask.
493
494
357=item aio_rmdir $pathname, $callback->($status) 495=item aio_rmdir $pathname, $callback->($status)
358 496
359Asynchronously rmdir (delete) a directory and call the callback with the 497Asynchronously rmdir (delete) a directory and call the callback with the
360result code. 498result code.
499
361 500
362=item aio_readdir $pathname, $callback->($entries) 501=item aio_readdir $pathname, $callback->($entries)
363 502
364Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 503Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
365directory (i.e. opendir + readdir + closedir). The entries will not be 504directory (i.e. opendir + readdir + closedir). The entries will not be
366sorted, and will B<NOT> include the C<.> and C<..> entries. 505sorted, and will B<NOT> include the C<.> and C<..> entries.
367 506
368The callback a single argument which is either C<undef> or an array-ref 507The callback a single argument which is either C<undef> or an array-ref
369with the filenames. 508with the filenames.
509
510
511=item aio_load $path, $data, $callback->($status)
512
513This is a composite request that tries to fully load the given file into
514memory. Status is the same as with aio_read.
515
516=cut
517
518sub aio_load($$;$) {
519 aio_block {
520 my ($path, undef, $cb) = @_;
521 my $data = \$_[1];
522
523 my $pri = aioreq_pri;
524 my $grp = aio_group $cb;
525
526 aioreq_pri $pri;
527 add $grp aio_open $path, O_RDONLY, 0, sub {
528 my $fh = shift
529 or return $grp->result (-1);
530
531 aioreq_pri $pri;
532 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
533 $grp->result ($_[0]);
534 };
535 };
536
537 $grp
538 }
539}
370 540
371=item aio_copy $srcpath, $dstpath, $callback->($status) 541=item aio_copy $srcpath, $dstpath, $callback->($status)
372 542
373Try to copy the I<file> (directories not supported as either source or 543Try to copy the I<file> (directories not supported as either source or
374destination) from C<$srcpath> to C<$dstpath> and call the callback with 544destination) from C<$srcpath> to C<$dstpath> and call the callback with
… …
384errors are being ignored. 554errors are being ignored.
385 555
386=cut 556=cut
387 557
388sub aio_copy($$;$) { 558sub aio_copy($$;$) {
559 aio_block {
389 my ($src, $dst, $cb) = @_; 560 my ($src, $dst, $cb) = @_;
390 561
391 my $pri = aioreq_pri; 562 my $pri = aioreq_pri;
392 my $grp = aio_group $cb; 563 my $grp = aio_group $cb;
393 564
394 aioreq_pri $pri; 565 aioreq_pri $pri;
395 add $grp aio_open $src, O_RDONLY, 0, sub { 566 add $grp aio_open $src, O_RDONLY, 0, sub {
396 if (my $src_fh = $_[0]) { 567 if (my $src_fh = $_[0]) {
397 my @stat = stat $src_fh; 568 my @stat = stat $src_fh;
398 569
399 aioreq_pri $pri; 570 aioreq_pri $pri;
400 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 571 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
401 if (my $dst_fh = $_[0]) { 572 if (my $dst_fh = $_[0]) {
402 aioreq_pri $pri; 573 aioreq_pri $pri;
403 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 574 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
404 if ($_[0] == $stat[7]) { 575 if ($_[0] == $stat[7]) {
405 $grp->result (0); 576 $grp->result (0);
406 close $src_fh; 577 close $src_fh;
407 578
408 # those should not normally block. should. should. 579 # those should not normally block. should. should.
409 utime $stat[8], $stat[9], $dst; 580 utime $stat[8], $stat[9], $dst;
410 chmod $stat[2] & 07777, $dst_fh; 581 chmod $stat[2] & 07777, $dst_fh;
411 chown $stat[4], $stat[5], $dst_fh; 582 chown $stat[4], $stat[5], $dst_fh;
412 close $dst_fh; 583 close $dst_fh;
413 } else { 584 } else {
414 $grp->result (-1); 585 $grp->result (-1);
415 close $src_fh; 586 close $src_fh;
416 close $dst_fh; 587 close $dst_fh;
417 588
418 aioreq $pri; 589 aioreq $pri;
419 add $grp aio_unlink $dst; 590 add $grp aio_unlink $dst;
591 }
420 } 592 };
593 } else {
594 $grp->result (-1);
421 }; 595 }
422 } else {
423 $grp->result (-1);
424 } 596 },
597
598 } else {
599 $grp->result (-1);
425 }, 600 }
426
427 } else {
428 $grp->result (-1);
429 } 601 };
602
603 $grp
430 }; 604 }
431
432 $grp
433} 605}
434 606
435=item aio_move $srcpath, $dstpath, $callback->($status) 607=item aio_move $srcpath, $dstpath, $callback->($status)
436 608
437Try to move the I<file> (directories not supported as either source or 609Try to move the I<file> (directories not supported as either source or
… …
443that is successful, unlinking the C<$srcpath>. 615that is successful, unlinking the C<$srcpath>.
444 616
445=cut 617=cut
446 618
447sub aio_move($$;$) { 619sub aio_move($$;$) {
620 aio_block {
448 my ($src, $dst, $cb) = @_; 621 my ($src, $dst, $cb) = @_;
449 622
450 my $pri = aioreq_pri; 623 my $pri = aioreq_pri;
451 my $grp = aio_group $cb; 624 my $grp = aio_group $cb;
452 625
453 aioreq_pri $pri; 626 aioreq_pri $pri;
454 add $grp aio_rename $src, $dst, sub { 627 add $grp aio_rename $src, $dst, sub {
455 if ($_[0] && $! == EXDEV) { 628 if ($_[0] && $! == EXDEV) {
456 aioreq_pri $pri; 629 aioreq_pri $pri;
457 add $grp aio_copy $src, $dst, sub { 630 add $grp aio_copy $src, $dst, sub {
631 $grp->result ($_[0]);
632
633 if (!$_[0]) {
634 aioreq_pri $pri;
635 add $grp aio_unlink $src;
636 }
637 };
638 } else {
458 $grp->result ($_[0]); 639 $grp->result ($_[0]);
459
460 if (!$_[0]) {
461 aioreq_pri $pri;
462 add $grp aio_unlink $src;
463 }
464 }; 640 }
465 } else {
466 $grp->result ($_[0]);
467 } 641 };
642
643 $grp
468 }; 644 }
469
470 $grp
471} 645}
472 646
473=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 647=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
474 648
475Scans a directory (similar to C<aio_readdir>) but additionally tries to 649Scans a directory (similar to C<aio_readdir>) but additionally tries to
… …
522as those tend to return 0 or 1 as link counts, which disables the 696as those tend to return 0 or 1 as link counts, which disables the
523directory counting heuristic. 697directory counting heuristic.
524 698
525=cut 699=cut
526 700
527sub aio_scandir($$$) { 701sub aio_scandir($$;$) {
702 aio_block {
528 my ($path, $maxreq, $cb) = @_; 703 my ($path, $maxreq, $cb) = @_;
529 704
530 my $pri = aioreq_pri; 705 my $pri = aioreq_pri;
531 706
532 my $grp = aio_group $cb; 707 my $grp = aio_group $cb;
533 708
534 $maxreq = 4 if $maxreq <= 0; 709 $maxreq = 4 if $maxreq <= 0;
535 710
536 # stat once 711 # stat once
537 aioreq_pri $pri;
538 add $grp aio_stat $path, sub {
539 return $grp->result () if $_[0];
540 my $now = time;
541 my $hash1 = join ":", (stat _)[0,1,3,7,9];
542
543 # read the directory entries
544 aioreq_pri $pri; 712 aioreq_pri $pri;
545 add $grp aio_readdir $path, sub { 713 add $grp aio_stat $path, sub {
546 my $entries = shift
547 or return $grp->result (); 714 return $grp->result () if $_[0];
715 my $now = time;
716 my $hash1 = join ":", (stat _)[0,1,3,7,9];
548 717
549 # stat the dir another time 718 # read the directory entries
550 aioreq_pri $pri; 719 aioreq_pri $pri;
720 add $grp aio_readdir $path, sub {
721 my $entries = shift
722 or return $grp->result ();
723
724 # stat the dir another time
725 aioreq_pri $pri;
551 add $grp aio_stat $path, sub { 726 add $grp aio_stat $path, sub {
552 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 727 my $hash2 = join ":", (stat _)[0,1,3,7,9];
553 728
554 my $ndirs; 729 my $ndirs;
555 730
556 # take the slow route if anything looks fishy 731 # take the slow route if anything looks fishy
557 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 732 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
558 $ndirs = -1; 733 $ndirs = -1;
559 } else { 734 } else {
560 # if nlink == 2, we are finished 735 # if nlink == 2, we are finished
561 # on non-posix-fs's, we rely on nlink < 2 736 # on non-posix-fs's, we rely on nlink < 2
562 $ndirs = (stat _)[3] - 2 737 $ndirs = (stat _)[3] - 2
563 or return $grp->result ([], $entries); 738 or return $grp->result ([], $entries);
564 } 739 }
565 740
566 # sort into likely dirs and likely nondirs 741 # sort into likely dirs and likely nondirs
567 # dirs == files without ".", short entries first 742 # dirs == files without ".", short entries first
568 $entries = [map $_->[0], 743 $entries = [map $_->[0],
569 sort { $b->[1] cmp $a->[1] } 744 sort { $b->[1] cmp $a->[1] }
570 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 745 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
571 @$entries]; 746 @$entries];
572 747
573 my (@dirs, @nondirs); 748 my (@dirs, @nondirs);
574 749
575 my $statgrp = add $grp aio_group sub { 750 my $statgrp = add $grp aio_group sub {
576 $grp->result (\@dirs, \@nondirs); 751 $grp->result (\@dirs, \@nondirs);
577 }; 752 };
578 753
579 limit $statgrp $maxreq; 754 limit $statgrp $maxreq;
580 feed $statgrp sub { 755 feed $statgrp sub {
581 return unless @$entries; 756 return unless @$entries;
582 my $entry = pop @$entries; 757 my $entry = pop @$entries;
583 758
584 aioreq_pri $pri; 759 aioreq_pri $pri;
585 add $statgrp aio_stat "$path/$entry/.", sub { 760 add $statgrp aio_stat "$path/$entry/.", sub {
586 if ($_[0] < 0) { 761 if ($_[0] < 0) {
587 push @nondirs, $entry; 762 push @nondirs, $entry;
588 } else { 763 } else {
589 # need to check for real directory 764 # need to check for real directory
590 aioreq_pri $pri; 765 aioreq_pri $pri;
591 add $statgrp aio_lstat "$path/$entry", sub { 766 add $statgrp aio_lstat "$path/$entry", sub {
592 if (-d _) { 767 if (-d _) {
593 push @dirs, $entry; 768 push @dirs, $entry;
594 769
595 unless (--$ndirs) { 770 unless (--$ndirs) {
596 push @nondirs, @$entries; 771 push @nondirs, @$entries;
597 feed $statgrp; 772 feed $statgrp;
773 }
774 } else {
775 push @nondirs, $entry;
598 } 776 }
599 } else {
600 push @nondirs, $entry;
601 } 777 }
602 } 778 }
603 } 779 };
604 }; 780 };
605 }; 781 };
606 }; 782 };
607 }; 783 };
784
785 $grp
608 }; 786 }
787}
609 788
789=item aio_rmtree $path, $callback->($status)
790
791Delete a directory tree starting (and including) C<$path>, return the
792status of the final C<rmdir> only. This is a composite request that
793uses C<aio_scandir> to recurse into and rmdir directories, and unlink
794everything else.
795
796=cut
797
798sub aio_rmtree;
799sub aio_rmtree($;$) {
800 aio_block {
801 my ($path, $cb) = @_;
802
803 my $pri = aioreq_pri;
804 my $grp = aio_group $cb;
805
806 aioreq_pri $pri;
807 add $grp aio_scandir $path, 0, sub {
808 my ($dirs, $nondirs) = @_;
809
810 my $dirgrp = aio_group sub {
811 add $grp aio_rmdir $path, sub {
812 $grp->result ($_[0]);
813 };
814 };
815
816 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
817 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
818
819 add $grp $dirgrp;
820 };
821
610 $grp 822 $grp
823 }
611} 824}
612 825
613=item aio_fsync $fh, $callback->($status) 826=item aio_fsync $fh, $callback->($status)
614 827
615Asynchronously call fsync on the given filehandle and call the callback 828Asynchronously call fsync on the given filehandle and call the callback
… …
829 1042
830=back 1043=back
831 1044
832=head2 SUPPORT FUNCTIONS 1045=head2 SUPPORT FUNCTIONS
833 1046
1047=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1048
834=over 4 1049=over 4
835 1050
836=item $fileno = IO::AIO::poll_fileno 1051=item $fileno = IO::AIO::poll_fileno
837 1052
838Return the I<request result pipe file descriptor>. This filehandle must be 1053Return the I<request result pipe file descriptor>. This filehandle must be
… …
842 1057
843See C<poll_cb> for an example. 1058See C<poll_cb> for an example.
844 1059
845=item IO::AIO::poll_cb 1060=item IO::AIO::poll_cb
846 1061
847Process all outstanding events on the result pipe. You have to call this 1062Process some outstanding events on the result pipe. You have to call this
848regularly. Returns the number of events processed. Returns immediately 1063regularly. Returns the number of events processed. Returns immediately
849when no events are outstanding. 1064when no events are outstanding. The amount of events processed depends on
1065the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
850 1066
851If not all requests were processed for whatever reason, the filehandle 1067If not all requests were processed for whatever reason, the filehandle
852will still be ready when C<poll_cb> returns. 1068will still be ready when C<poll_cb> returns.
853 1069
854Example: Install an Event watcher that automatically calls 1070Example: Install an Event watcher that automatically calls
… …
856 1072
857 Event->io (fd => IO::AIO::poll_fileno, 1073 Event->io (fd => IO::AIO::poll_fileno,
858 poll => 'r', async => 1, 1074 poll => 'r', async => 1,
859 cb => \&IO::AIO::poll_cb); 1075 cb => \&IO::AIO::poll_cb);
860 1076
861=item IO::AIO::poll_some $max_requests 1077=item IO::AIO::max_poll_reqs $nreqs
862 1078
863Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1079=item IO::AIO::max_poll_time $seconds
864at a time.
865 1080
866Useful if you want to ensure some level of interactiveness when perl is 1081These set the maximum number of requests (default C<0>, meaning infinity)
867not fast enough to process all requests in time. 1082that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1083the maximum amount of time (default C<0>, meaning infinity) spent in
1084C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1085of time C<poll_cb> is allowed to use).
1086
1087Setting C<max_poll_time> to a non-zero value creates an overhead of one
1088syscall per request processed, which is not normally a problem unless your
1089callbacks are really really fast or your OS is really really slow (I am
1090not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1091
1092Setting these is useful if you want to ensure some level of
1093interactiveness when perl is not fast enough to process all requests in
1094time.
1095
1096For interactive programs, values such as C<0.01> to C<0.1> should be fine.
868 1097
869Example: Install an Event watcher that automatically calls 1098Example: Install an Event watcher that automatically calls
870IO::AIO::poll_some with low priority, to ensure that other parts of the 1099IO::AIO::poll_cb with low priority, to ensure that other parts of the
871program get the CPU sometimes even under high AIO load. 1100program get the CPU sometimes even under high AIO load.
872 1101
1102 # try not to spend much more than 0.1s in poll_cb
1103 IO::AIO::max_poll_time 0.1;
1104
1105 # use a low priority so other tasks have priority
873 Event->io (fd => IO::AIO::poll_fileno, 1106 Event->io (fd => IO::AIO::poll_fileno,
874 poll => 'r', nice => 1, 1107 poll => 'r', nice => 1,
875 cb => sub { IO::AIO::poll_some 256 }); 1108 cb => &IO::AIO::poll_cb);
876 1109
877=item IO::AIO::poll_wait 1110=item IO::AIO::poll_wait
878 1111
1112If there are any outstanding requests and none of them in the result
879Wait till the result filehandle becomes ready for reading (simply does a 1113phase, wait till the result filehandle becomes ready for reading (simply
880C<select> on the filehandle. This is useful if you want to synchronously wait 1114does a C<select> on the filehandle. This is useful if you want to
881for some requests to finish). 1115synchronously wait for some requests to finish).
882 1116
883See C<nreqs> for an example. 1117See C<nreqs> for an example.
884 1118
1119=item IO::AIO::poll
1120
1121Waits until some requests have been handled.
1122
1123Returns the number of requests processed, but is otherwise strictly
1124equivalent to:
1125
1126 IO::AIO::poll_wait, IO::AIO::poll_cb
1127
885=item IO::AIO::nreqs 1128=item IO::AIO::flush
886 1129
887Returns the number of requests currently in the ready, execute or pending 1130Wait till all outstanding AIO requests have been handled.
888states (i.e. for which their callback has not been invoked yet).
889 1131
890Example: wait till there are no outstanding requests anymore: 1132Strictly equivalent to:
891 1133
892 IO::AIO::poll_wait, IO::AIO::poll_cb 1134 IO::AIO::poll_wait, IO::AIO::poll_cb
893 while IO::AIO::nreqs; 1135 while IO::AIO::nreqs;
894 1136
895=item IO::AIO::nready 1137=back
896 1138
897Returns the number of requests currently in the ready state (not yet 1139=head3 CONTROLLING THE NUMBER OF THREADS
898executed).
899 1140
900=item IO::AIO::npending 1141=over
901
902Returns the number of requests currently in the pending state (executed,
903but not yet processed by poll_cb).
904
905=item IO::AIO::flush
906
907Wait till all outstanding AIO requests have been handled.
908
909Strictly equivalent to:
910
911 IO::AIO::poll_wait, IO::AIO::poll_cb
912 while IO::AIO::nreqs;
913
914=item IO::AIO::poll
915
916Waits until some requests have been handled.
917
918Strictly equivalent to:
919
920 IO::AIO::poll_wait, IO::AIO::poll_cb
921 if IO::AIO::nreqs;
922 1142
923=item IO::AIO::min_parallel $nthreads 1143=item IO::AIO::min_parallel $nthreads
924 1144
925Set the minimum number of AIO threads to C<$nthreads>. The current 1145Set the minimum number of AIO threads to C<$nthreads>. The current
926default is C<8>, which means eight asynchronous operations can execute 1146default is C<8>, which means eight asynchronous operations can execute
927concurrently at any one time (the number of outstanding requests, 1147concurrently at any one time (the number of outstanding requests,
928however, is unlimited). 1148however, is unlimited).
929 1149
930IO::AIO starts threads only on demand, when an AIO request is queued and 1150IO::AIO starts threads only on demand, when an AIO request is queued and
931no free thread exists. 1151no free thread exists. Please note that queueing up a hundred requests can
1152create demand for a hundred threads, even if it turns out that everything
1153is in the cache and could have been processed faster by a single thread.
932 1154
933It is recommended to keep the number of threads relatively low, as some 1155It is recommended to keep the number of threads relatively low, as some
934Linux kernel versions will scale negatively with the number of threads 1156Linux kernel versions will scale negatively with the number of threads
935(higher parallelity => MUCH higher latency). With current Linux 2.6 1157(higher parallelity => MUCH higher latency). With current Linux 2.6
936versions, 4-32 threads should be fine. 1158versions, 4-32 threads should be fine.
… …
950This module automatically runs C<max_parallel 0> at program end, to ensure 1172This module automatically runs C<max_parallel 0> at program end, to ensure
951that all threads are killed and that there are no outstanding requests. 1173that all threads are killed and that there are no outstanding requests.
952 1174
953Under normal circumstances you don't need to call this function. 1175Under normal circumstances you don't need to call this function.
954 1176
1177=item IO::AIO::max_idle $nthreads
1178
1179Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1180threads that did not get a request to process within 10 seconds). That
1181means if a thread becomes idle while C<$nthreads> other threads are also
1182idle, it will free its resources and exit.
1183
1184This is useful when you allow a large number of threads (e.g. 100 or 1000)
1185to allow for extremely high load situations, but want to free resources
1186under normal circumstances (1000 threads can easily consume 30MB of RAM).
1187
1188The default is probably ok in most situations, especially if thread
1189creation is fast. If thread creation is very slow on your system you might
1190want to use larger values.
1191
955=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1192=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
956 1193
957This is a very bad function to use in interactive programs because it 1194This is a very bad function to use in interactive programs because it
958blocks, and a bad way to reduce concurrency because it is inexact: Better 1195blocks, and a bad way to reduce concurrency because it is inexact: Better
959use an C<aio_group> together with a feed callback. 1196use an C<aio_group> together with a feed callback.
… …
970C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1207C<max_oustsanding> is mainly useful in simple scripts (with low values) or
971as a stop gap to shield against fatal memory overflow (with large values). 1208as a stop gap to shield against fatal memory overflow (with large values).
972 1209
973=back 1210=back
974 1211
1212=head3 STATISTICAL INFORMATION
1213
1214=over
1215
1216=item IO::AIO::nreqs
1217
1218Returns the number of requests currently in the ready, execute or pending
1219states (i.e. for which their callback has not been invoked yet).
1220
1221Example: wait till there are no outstanding requests anymore:
1222
1223 IO::AIO::poll_wait, IO::AIO::poll_cb
1224 while IO::AIO::nreqs;
1225
1226=item IO::AIO::nready
1227
1228Returns the number of requests currently in the ready state (not yet
1229executed).
1230
1231=item IO::AIO::npending
1232
1233Returns the number of requests currently in the pending state (executed,
1234but not yet processed by poll_cb).
1235
1236=back
1237
975=cut 1238=cut
976 1239
977# support function to convert a fd into a perl filehandle 1240# support function to convert a fd into a perl filehandle
978sub _fd2fh { 1241sub _fd2fh {
979 return undef if $_[0] < 0; 1242 return undef if $_[0] < 0;
… …
990 *$sym 1253 *$sym
991} 1254}
992 1255
993min_parallel 8; 1256min_parallel 8;
994 1257
995END { 1258END { flush }
996 flush;
997};
998 1259
9991; 12601;
1000 1261
1001=head2 FORK BEHAVIOUR 1262=head2 FORK BEHAVIOUR
1002 1263

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