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Revision 1.83 by root, Fri Oct 27 20:11:58 2006 UTC vs.
Revision 1.113 by root, Thu Sep 20 14:06:21 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
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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
68example sockets), using these functions on file descriptors that
69support nonblocking operation (again, sockets, pipes etc.) is very
70inefficient. Use an event loop for that (such as the L<Event|Event>
71module): IO::AIO will naturally fit into such an event loop itself.
55 72
56In this version, a number of threads are started that execute your 73In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 74requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 75in 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 76to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 77functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 78not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 79files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 80aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 81using threads anyway.
65 82
66Although the module will work with in the presence of other (Perl-) 83Although the module will work in the presence of other (Perl-) threads,
67threads, it is currently not reentrant in any way, so use appropriate 84it is currently not reentrant in any way, so use appropriate locking
68locking yourself, always call C<poll_cb> from within the same thread, or 85yourself, always call C<poll_cb> from within the same thread, or never
69never call C<poll_cb> (or other C<aio_> functions) recursively. 86call C<poll_cb> (or other C<aio_> functions) recursively.
87
88=head2 EXAMPLE
89
90This is a simple example that uses the Event module and loads
91F</etc/passwd> asynchronously:
92
93 use Fcntl;
94 use Event;
95 use IO::AIO;
96
97 # register the IO::AIO callback with Event
98 Event->io (fd => IO::AIO::poll_fileno,
99 poll => 'r',
100 cb => \&IO::AIO::poll_cb);
101
102 # queue the request to open /etc/passwd
103 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 my $fh = shift
105 or die "error while opening: $!";
106
107 # stat'ing filehandles is generally non-blocking
108 my $size = -s $fh;
109
110 # queue a request to read the file
111 my $contents;
112 aio_read $fh, 0, $size, $contents, 0, sub {
113 $_[0] == $size
114 or die "short read: $!";
115
116 close $fh;
117
118 # file contents now in $contents
119 print $contents;
120
121 # exit event loop and program
122 Event::unloop;
123 };
124 };
125
126 # possibly queue up other requests, or open GUI windows,
127 # check for sockets etc. etc.
128
129 # process events as long as there are some:
130 Event::loop;
70 131
71=head1 REQUEST ANATOMY AND LIFETIME 132=head1 REQUEST ANATOMY AND LIFETIME
72 133
73Every C<aio_*> function creates a request. which is a C data structure not 134Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 135directly visible to Perl.
… …
116Request has reached the end of its lifetime and holds no resources anymore 177Request 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 178(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 179aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 180result in a runtime error).
120 181
182=back
183
121=cut 184=cut
122 185
123package IO::AIO; 186package IO::AIO;
124 187
125no warnings; 188no warnings;
126use strict 'vars'; 189use strict 'vars';
127 190
128use base 'Exporter'; 191use base 'Exporter';
129 192
130BEGIN { 193BEGIN {
131 our $VERSION = '2.0'; 194 our $VERSION = '2.4';
132 195
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 196 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 197 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 198 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
136 aio_copy aio_group aio_nop aio_mknod); 199 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
200 aio_chown aio_chmod aio_utime aio_truncate);
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
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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
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201 aio_read $_[0], ..., sub { 271 aio_read $_[0], ..., sub {
202 ... 272 ...
203 }; 273 };
204 }; 274 };
205 275
276
206=item aioreq_nice $pri_adjust 277=item aioreq_nice $pri_adjust
207 278
208Similar to C<aioreq_pri>, but subtracts the given value from the current 279Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 280priority, so the effect is cumulative.
281
210 282
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 283=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 284
213Asynchronously open or create a file and call the callback with a newly 285Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 286created filehandle for the file.
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220list. They are the same as used by C<sysopen>. 292list. They are the same as used by C<sysopen>.
221 293
222Likewise, C<$mode> specifies the mode of the newly created file, if it 294Likewise, C<$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>, 295didn'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, 296except 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). 297and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
298by the umask in effect then the request is being executed, so better never
299change the umask.
226 300
227Example: 301Example:
228 302
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 303 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 304 if ($_[0]) {
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233 } else { 307 } else {
234 die "open failed: $!\n"; 308 die "open failed: $!\n";
235 } 309 }
236 }; 310 };
237 311
312
238=item aio_close $fh, $callback->($status) 313=item aio_close $fh, $callback->($status)
239 314
240Asynchronously close a file and call the callback with the result 315Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 316code. I<WARNING:> although accepted, you should not pass in a perl
242filehandle here, as perl will likely close the file descriptor another 317filehandle here, as perl will likely close the file descriptor another
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244C<close> or just let filehandles go out of scope. 319C<close> or just let filehandles go out of scope.
245 320
246This is supposed to be a bug in the API, so that might change. It's 321This is supposed to be a bug in the API, so that might change. It's
247therefore best to avoid this function. 322therefore best to avoid this function.
248 323
324
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 325=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 326
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 327=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 328
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 329Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254into the scalar given by C<data> and offset C<dataoffset> and calls the 330into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255callback without the actual number of bytes read (or -1 on error, just 331callback without the actual number of bytes read (or -1 on error, just
256like the syscall). 332like the syscall).
257 333
334If C<$offset> is undefined, then the current file descriptor offset will
335be used (and updated), otherwise the file descriptor offset will not be
336changed by these calls.
337
338If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
339
340If C<$dataoffset> is less than zero, it will be counted from the end of
341C<$data>.
342
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 343The C<$data> scalar I<MUST NOT> be modified in any way while the request
259is outstanding. Modifying it can result in segfaults or WW3 (if the 344is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 345the necessary/optional hardware is installed).
261 346
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 347Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 348offset C<0> within the scalar:
264 349
265 aio_read $fh, 7, 15, $buffer, 0, sub { 350 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 351 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 352 print "read $_[0] bytes: <$buffer>\n";
268 }; 353 };
354
269 355
270=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 356=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
271 357
272Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 358Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
273reading at byte offset C<$in_offset>, and starts writing at the current 359reading at byte offset C<$in_offset>, and starts writing at the current
… …
287C<$in_fh> than are written, and there is no way to find out how many 373C<$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 374bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
289provides the number of bytes written to C<$out_fh>. Only if the result 375provides the number of bytes written to C<$out_fh>. Only if the result
290value equals C<$length> one can assume that C<$length> bytes have been 376value equals C<$length> one can assume that C<$length> bytes have been
291read. 377read.
378
292 379
293=item aio_readahead $fh,$offset,$length, $callback->($retval) 380=item aio_readahead $fh,$offset,$length, $callback->($retval)
294 381
295C<aio_readahead> populates the page cache with data from a file so that 382C<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<$offset> 383subsequent reads from that file will not block on disk I/O. The C<$offset>
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302file. The current file offset of the file is left unchanged. 389file. The current file offset of the file is left unchanged.
303 390
304If that syscall doesn't exist (likely if your OS isn't Linux) it will be 391If 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. 392emulated by simply reading the data, which would have a similar effect.
306 393
394
307=item aio_stat $fh_or_path, $callback->($status) 395=item aio_stat $fh_or_path, $callback->($status)
308 396
309=item aio_lstat $fh, $callback->($status) 397=item aio_lstat $fh, $callback->($status)
310 398
311Works like perl's C<stat> or C<lstat> in void context. The callback will 399Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
324 aio_stat "/etc/passwd", sub { 412 aio_stat "/etc/passwd", sub {
325 $_[0] and die "stat failed: $!"; 413 $_[0] and die "stat failed: $!";
326 print "size is ", -s _, "\n"; 414 print "size is ", -s _, "\n";
327 }; 415 };
328 416
417
418=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
419
420Works like perl's C<utime> function (including the special case of $atime
421and $mtime being undef). Fractional times are supported if the underlying
422syscalls support them.
423
424When called with a pathname, uses utimes(2) if available, otherwise
425utime(2). If called on a file descriptor, uses futimes(2) if available,
426otherwise returns ENOSYS, so this is not portable.
427
428Examples:
429
430 # set atime and mtime to current time (basically touch(1)):
431 aio_utime "path", undef, undef;
432 # set atime to current time and mtime to beginning of the epoch:
433 aio_utime "path", time, undef; # undef==0
434
435
436=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
437
438Works like perl's C<chown> function, except that C<undef> for either $uid
439or $gid is being interpreted as "do not change" (but -1 can also be used).
440
441Examples:
442
443 # same as "chown root path" in the shell:
444 aio_chown "path", 0, -1;
445 # same as above:
446 aio_chown "path", 0, undef;
447
448
449=item aio_truncate $fh_or_path, $offset, $callback->($status)
450
451Works like truncate(2) or ftruncate(2).
452
453
454=item aio_chmod $fh_or_path, $mode, $callback->($status)
455
456Works like perl's C<chmod> function.
457
458
329=item aio_unlink $pathname, $callback->($status) 459=item aio_unlink $pathname, $callback->($status)
330 460
331Asynchronously unlink (delete) a file and call the callback with the 461Asynchronously unlink (delete) a file and call the callback with the
332result code. 462result code.
333 463
464
334=item aio_mknod $path, $mode, $dev, $callback->($status) 465=item aio_mknod $path, $mode, $dev, $callback->($status)
335 466
467[EXPERIMENTAL]
468
336Asynchronously create a device node (or fifo). See mknod(2). 469Asynchronously create a device node (or fifo). See mknod(2).
337 470
338The only portable (POSIX) way of calling this function is: 471The only (POSIX-) portable way of calling this function is:
339 472
340 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 473 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
474
341 475
342=item aio_link $srcpath, $dstpath, $callback->($status) 476=item aio_link $srcpath, $dstpath, $callback->($status)
343 477
344Asynchronously create a new link to the existing object at C<$srcpath> at 478Asynchronously create a new link to the existing object at C<$srcpath> at
345the path C<$dstpath> and call the callback with the result code. 479the path C<$dstpath> and call the callback with the result code.
346 480
481
347=item aio_symlink $srcpath, $dstpath, $callback->($status) 482=item aio_symlink $srcpath, $dstpath, $callback->($status)
348 483
349Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 484Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
350the path C<$dstpath> and call the callback with the result code. 485the path C<$dstpath> and call the callback with the result code.
351 486
487
488=item aio_readlink $path, $callback->($link)
489
490Asynchronously read the symlink specified by C<$path> and pass it to
491the callback. If an error occurs, nothing or undef gets passed to the
492callback.
493
494
352=item aio_rename $srcpath, $dstpath, $callback->($status) 495=item aio_rename $srcpath, $dstpath, $callback->($status)
353 496
354Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 497Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
355rename(2) and call the callback with the result code. 498rename(2) and call the callback with the result code.
356 499
500
501=item aio_mkdir $pathname, $mode, $callback->($status)
502
503Asynchronously mkdir (create) a directory and call the callback with
504the result code. C<$mode> will be modified by the umask at the time the
505request is executed, so do not change your umask.
506
507
357=item aio_rmdir $pathname, $callback->($status) 508=item aio_rmdir $pathname, $callback->($status)
358 509
359Asynchronously rmdir (delete) a directory and call the callback with the 510Asynchronously rmdir (delete) a directory and call the callback with the
360result code. 511result code.
512
361 513
362=item aio_readdir $pathname, $callback->($entries) 514=item aio_readdir $pathname, $callback->($entries)
363 515
364Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 516Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
365directory (i.e. opendir + readdir + closedir). The entries will not be 517directory (i.e. opendir + readdir + closedir). The entries will not be
366sorted, and will B<NOT> include the C<.> and C<..> entries. 518sorted, and will B<NOT> include the C<.> and C<..> entries.
367 519
368The callback a single argument which is either C<undef> or an array-ref 520The callback a single argument which is either C<undef> or an array-ref
369with the filenames. 521with the filenames.
522
523
524=item aio_load $path, $data, $callback->($status)
525
526This is a composite request that tries to fully load the given file into
527memory. Status is the same as with aio_read.
528
529=cut
530
531sub aio_load($$;$) {
532 aio_block {
533 my ($path, undef, $cb) = @_;
534 my $data = \$_[1];
535
536 my $pri = aioreq_pri;
537 my $grp = aio_group $cb;
538
539 aioreq_pri $pri;
540 add $grp aio_open $path, O_RDONLY, 0, sub {
541 my $fh = shift
542 or return $grp->result (-1);
543
544 aioreq_pri $pri;
545 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
546 $grp->result ($_[0]);
547 };
548 };
549
550 $grp
551 }
552}
370 553
371=item aio_copy $srcpath, $dstpath, $callback->($status) 554=item aio_copy $srcpath, $dstpath, $callback->($status)
372 555
373Try to copy the I<file> (directories not supported as either source or 556Try to copy the I<file> (directories not supported as either source or
374destination) from C<$srcpath> to C<$dstpath> and call the callback with 557destination) from C<$srcpath> to C<$dstpath> and call the callback with
… …
384errors are being ignored. 567errors are being ignored.
385 568
386=cut 569=cut
387 570
388sub aio_copy($$;$) { 571sub aio_copy($$;$) {
572 aio_block {
389 my ($src, $dst, $cb) = @_; 573 my ($src, $dst, $cb) = @_;
390 574
391 my $pri = aioreq_pri; 575 my $pri = aioreq_pri;
392 my $grp = aio_group $cb; 576 my $grp = aio_group $cb;
393 577
394 aioreq_pri $pri; 578 aioreq_pri $pri;
395 add $grp aio_open $src, O_RDONLY, 0, sub { 579 add $grp aio_open $src, O_RDONLY, 0, sub {
396 if (my $src_fh = $_[0]) { 580 if (my $src_fh = $_[0]) {
397 my @stat = stat $src_fh; 581 my @stat = stat $src_fh;
398 582
399 aioreq_pri $pri; 583 aioreq_pri $pri;
400 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 584 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
401 if (my $dst_fh = $_[0]) { 585 if (my $dst_fh = $_[0]) {
402 aioreq_pri $pri; 586 aioreq_pri $pri;
403 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 587 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
404 if ($_[0] == $stat[7]) { 588 if ($_[0] == $stat[7]) {
405 $grp->result (0); 589 $grp->result (0);
406 close $src_fh; 590 close $src_fh;
407 591
408 # those should not normally block. should. should. 592 # those should not normally block. should. should.
409 utime $stat[8], $stat[9], $dst; 593 utime $stat[8], $stat[9], $dst;
410 chmod $stat[2] & 07777, $dst_fh; 594 chmod $stat[2] & 07777, $dst_fh;
411 chown $stat[4], $stat[5], $dst_fh; 595 chown $stat[4], $stat[5], $dst_fh;
412 close $dst_fh; 596 close $dst_fh;
413 } else { 597 } else {
414 $grp->result (-1); 598 $grp->result (-1);
415 close $src_fh; 599 close $src_fh;
416 close $dst_fh; 600 close $dst_fh;
417 601
418 aioreq $pri; 602 aioreq $pri;
419 add $grp aio_unlink $dst; 603 add $grp aio_unlink $dst;
604 }
420 } 605 };
606 } else {
607 $grp->result (-1);
421 }; 608 }
422 } else {
423 $grp->result (-1);
424 } 609 },
610
611 } else {
612 $grp->result (-1);
425 }, 613 }
426
427 } else {
428 $grp->result (-1);
429 } 614 };
615
616 $grp
430 }; 617 }
431
432 $grp
433} 618}
434 619
435=item aio_move $srcpath, $dstpath, $callback->($status) 620=item aio_move $srcpath, $dstpath, $callback->($status)
436 621
437Try to move the I<file> (directories not supported as either source or 622Try to move the I<file> (directories not supported as either source or
… …
443that is successful, unlinking the C<$srcpath>. 628that is successful, unlinking the C<$srcpath>.
444 629
445=cut 630=cut
446 631
447sub aio_move($$;$) { 632sub aio_move($$;$) {
633 aio_block {
448 my ($src, $dst, $cb) = @_; 634 my ($src, $dst, $cb) = @_;
449 635
450 my $pri = aioreq_pri; 636 my $pri = aioreq_pri;
451 my $grp = aio_group $cb; 637 my $grp = aio_group $cb;
452 638
453 aioreq_pri $pri; 639 aioreq_pri $pri;
454 add $grp aio_rename $src, $dst, sub { 640 add $grp aio_rename $src, $dst, sub {
455 if ($_[0] && $! == EXDEV) { 641 if ($_[0] && $! == EXDEV) {
456 aioreq_pri $pri; 642 aioreq_pri $pri;
457 add $grp aio_copy $src, $dst, sub { 643 add $grp aio_copy $src, $dst, sub {
644 $grp->result ($_[0]);
645
646 if (!$_[0]) {
647 aioreq_pri $pri;
648 add $grp aio_unlink $src;
649 }
650 };
651 } else {
458 $grp->result ($_[0]); 652 $grp->result ($_[0]);
459
460 if (!$_[0]) {
461 aioreq_pri $pri;
462 add $grp aio_unlink $src;
463 }
464 }; 653 }
465 } else {
466 $grp->result ($_[0]);
467 } 654 };
655
656 $grp
468 }; 657 }
469
470 $grp
471} 658}
472 659
473=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 660=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
474 661
475Scans a directory (similar to C<aio_readdir>) but additionally tries to 662Scans 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 709as those tend to return 0 or 1 as link counts, which disables the
523directory counting heuristic. 710directory counting heuristic.
524 711
525=cut 712=cut
526 713
527sub aio_scandir($$$) { 714sub aio_scandir($$;$) {
715 aio_block {
528 my ($path, $maxreq, $cb) = @_; 716 my ($path, $maxreq, $cb) = @_;
529 717
530 my $pri = aioreq_pri; 718 my $pri = aioreq_pri;
531 719
532 my $grp = aio_group $cb; 720 my $grp = aio_group $cb;
533 721
534 $maxreq = 4 if $maxreq <= 0; 722 $maxreq = 4 if $maxreq <= 0;
535 723
536 # stat once 724 # 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; 725 aioreq_pri $pri;
545 add $grp aio_readdir $path, sub { 726 add $grp aio_stat $path, sub {
546 my $entries = shift
547 or return $grp->result (); 727 return $grp->result () if $_[0];
728 my $now = time;
729 my $hash1 = join ":", (stat _)[0,1,3,7,9];
548 730
549 # stat the dir another time 731 # read the directory entries
550 aioreq_pri $pri; 732 aioreq_pri $pri;
733 add $grp aio_readdir $path, sub {
734 my $entries = shift
735 or return $grp->result ();
736
737 # stat the dir another time
738 aioreq_pri $pri;
551 add $grp aio_stat $path, sub { 739 add $grp aio_stat $path, sub {
552 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 740 my $hash2 = join ":", (stat _)[0,1,3,7,9];
553 741
554 my $ndirs; 742 my $ndirs;
555 743
556 # take the slow route if anything looks fishy 744 # take the slow route if anything looks fishy
557 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 745 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
558 $ndirs = -1; 746 $ndirs = -1;
559 } else { 747 } else {
560 # if nlink == 2, we are finished 748 # if nlink == 2, we are finished
561 # on non-posix-fs's, we rely on nlink < 2 749 # on non-posix-fs's, we rely on nlink < 2
562 $ndirs = (stat _)[3] - 2 750 $ndirs = (stat _)[3] - 2
563 or return $grp->result ([], $entries); 751 or return $grp->result ([], $entries);
564 } 752 }
565 753
566 # sort into likely dirs and likely nondirs 754 # sort into likely dirs and likely nondirs
567 # dirs == files without ".", short entries first 755 # dirs == files without ".", short entries first
568 $entries = [map $_->[0], 756 $entries = [map $_->[0],
569 sort { $b->[1] cmp $a->[1] } 757 sort { $b->[1] cmp $a->[1] }
570 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 758 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
571 @$entries]; 759 @$entries];
572 760
573 my (@dirs, @nondirs); 761 my (@dirs, @nondirs);
574 762
575 my $statgrp = add $grp aio_group sub { 763 my $statgrp = add $grp aio_group sub {
576 $grp->result (\@dirs, \@nondirs); 764 $grp->result (\@dirs, \@nondirs);
577 }; 765 };
578 766
579 limit $statgrp $maxreq; 767 limit $statgrp $maxreq;
580 feed $statgrp sub { 768 feed $statgrp sub {
581 return unless @$entries; 769 return unless @$entries;
582 my $entry = pop @$entries; 770 my $entry = pop @$entries;
583 771
584 aioreq_pri $pri; 772 aioreq_pri $pri;
585 add $statgrp aio_stat "$path/$entry/.", sub { 773 add $statgrp aio_stat "$path/$entry/.", sub {
586 if ($_[0] < 0) { 774 if ($_[0] < 0) {
587 push @nondirs, $entry; 775 push @nondirs, $entry;
588 } else { 776 } else {
589 # need to check for real directory 777 # need to check for real directory
590 aioreq_pri $pri; 778 aioreq_pri $pri;
591 add $statgrp aio_lstat "$path/$entry", sub { 779 add $statgrp aio_lstat "$path/$entry", sub {
592 if (-d _) { 780 if (-d _) {
593 push @dirs, $entry; 781 push @dirs, $entry;
594 782
595 unless (--$ndirs) { 783 unless (--$ndirs) {
596 push @nondirs, @$entries; 784 push @nondirs, @$entries;
597 feed $statgrp; 785 feed $statgrp;
786 }
787 } else {
788 push @nondirs, $entry;
598 } 789 }
599 } else {
600 push @nondirs, $entry;
601 } 790 }
602 } 791 }
603 } 792 };
604 }; 793 };
605 }; 794 };
606 }; 795 };
607 }; 796 };
797
798 $grp
608 }; 799 }
800}
609 801
802=item aio_rmtree $path, $callback->($status)
803
804Delete a directory tree starting (and including) C<$path>, return the
805status of the final C<rmdir> only. This is a composite request that
806uses C<aio_scandir> to recurse into and rmdir directories, and unlink
807everything else.
808
809=cut
810
811sub aio_rmtree;
812sub aio_rmtree($;$) {
813 aio_block {
814 my ($path, $cb) = @_;
815
816 my $pri = aioreq_pri;
817 my $grp = aio_group $cb;
818
819 aioreq_pri $pri;
820 add $grp aio_scandir $path, 0, sub {
821 my ($dirs, $nondirs) = @_;
822
823 my $dirgrp = aio_group sub {
824 add $grp aio_rmdir $path, sub {
825 $grp->result ($_[0]);
826 };
827 };
828
829 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
830 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
831
832 add $grp $dirgrp;
833 };
834
610 $grp 835 $grp
836 }
611} 837}
612 838
613=item aio_fsync $fh, $callback->($status) 839=item aio_fsync $fh, $callback->($status)
614 840
615Asynchronously call fsync on the given filehandle and call the callback 841Asynchronously call fsync on the given filehandle and call the callback
… …
829 1055
830=back 1056=back
831 1057
832=head2 SUPPORT FUNCTIONS 1058=head2 SUPPORT FUNCTIONS
833 1059
1060=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1061
834=over 4 1062=over 4
835 1063
836=item $fileno = IO::AIO::poll_fileno 1064=item $fileno = IO::AIO::poll_fileno
837 1065
838Return the I<request result pipe file descriptor>. This filehandle must be 1066Return the I<request result pipe file descriptor>. This filehandle must be
… …
842 1070
843See C<poll_cb> for an example. 1071See C<poll_cb> for an example.
844 1072
845=item IO::AIO::poll_cb 1073=item IO::AIO::poll_cb
846 1074
847Process all outstanding events on the result pipe. You have to call this 1075Process some outstanding events on the result pipe. You have to call this
848regularly. Returns the number of events processed. Returns immediately 1076regularly. Returns the number of events processed. Returns immediately
849when no events are outstanding. 1077when no events are outstanding. The amount of events processed depends on
1078the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
850 1079
851If not all requests were processed for whatever reason, the filehandle 1080If not all requests were processed for whatever reason, the filehandle
852will still be ready when C<poll_cb> returns. 1081will still be ready when C<poll_cb> returns.
853 1082
854Example: Install an Event watcher that automatically calls 1083Example: Install an Event watcher that automatically calls
… …
856 1085
857 Event->io (fd => IO::AIO::poll_fileno, 1086 Event->io (fd => IO::AIO::poll_fileno,
858 poll => 'r', async => 1, 1087 poll => 'r', async => 1,
859 cb => \&IO::AIO::poll_cb); 1088 cb => \&IO::AIO::poll_cb);
860 1089
861=item IO::AIO::poll_some $max_requests 1090=item IO::AIO::max_poll_reqs $nreqs
862 1091
863Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1092=item IO::AIO::max_poll_time $seconds
864at a time.
865 1093
866Useful if you want to ensure some level of interactiveness when perl is 1094These set the maximum number of requests (default C<0>, meaning infinity)
867not fast enough to process all requests in time. 1095that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1096the maximum amount of time (default C<0>, meaning infinity) spent in
1097C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1098of time C<poll_cb> is allowed to use).
1099
1100Setting C<max_poll_time> to a non-zero value creates an overhead of one
1101syscall per request processed, which is not normally a problem unless your
1102callbacks are really really fast or your OS is really really slow (I am
1103not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1104
1105Setting these is useful if you want to ensure some level of
1106interactiveness when perl is not fast enough to process all requests in
1107time.
1108
1109For interactive programs, values such as C<0.01> to C<0.1> should be fine.
868 1110
869Example: Install an Event watcher that automatically calls 1111Example: Install an Event watcher that automatically calls
870IO::AIO::poll_some with low priority, to ensure that other parts of the 1112IO::AIO::poll_cb with low priority, to ensure that other parts of the
871program get the CPU sometimes even under high AIO load. 1113program get the CPU sometimes even under high AIO load.
872 1114
1115 # try not to spend much more than 0.1s in poll_cb
1116 IO::AIO::max_poll_time 0.1;
1117
1118 # use a low priority so other tasks have priority
873 Event->io (fd => IO::AIO::poll_fileno, 1119 Event->io (fd => IO::AIO::poll_fileno,
874 poll => 'r', nice => 1, 1120 poll => 'r', nice => 1,
875 cb => sub { IO::AIO::poll_some 256 }); 1121 cb => &IO::AIO::poll_cb);
876 1122
877=item IO::AIO::poll_wait 1123=item IO::AIO::poll_wait
878 1124
1125If there are any outstanding requests and none of them in the result
879Wait till the result filehandle becomes ready for reading (simply does a 1126phase, wait till the result filehandle becomes ready for reading (simply
880C<select> on the filehandle. This is useful if you want to synchronously wait 1127does a C<select> on the filehandle. This is useful if you want to
881for some requests to finish). 1128synchronously wait for some requests to finish).
882 1129
883See C<nreqs> for an example. 1130See C<nreqs> for an example.
884 1131
1132=item IO::AIO::poll
1133
1134Waits until some requests have been handled.
1135
1136Returns the number of requests processed, but is otherwise strictly
1137equivalent to:
1138
1139 IO::AIO::poll_wait, IO::AIO::poll_cb
1140
885=item IO::AIO::nreqs 1141=item IO::AIO::flush
886 1142
887Returns the number of requests currently in the ready, execute or pending 1143Wait till all outstanding AIO requests have been handled.
888states (i.e. for which their callback has not been invoked yet).
889 1144
890Example: wait till there are no outstanding requests anymore: 1145Strictly equivalent to:
891 1146
892 IO::AIO::poll_wait, IO::AIO::poll_cb 1147 IO::AIO::poll_wait, IO::AIO::poll_cb
893 while IO::AIO::nreqs; 1148 while IO::AIO::nreqs;
894 1149
895=item IO::AIO::nready 1150=back
896 1151
897Returns the number of requests currently in the ready state (not yet 1152=head3 CONTROLLING THE NUMBER OF THREADS
898executed).
899 1153
900=item IO::AIO::npending 1154=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 1155
923=item IO::AIO::min_parallel $nthreads 1156=item IO::AIO::min_parallel $nthreads
924 1157
925Set the minimum number of AIO threads to C<$nthreads>. The current 1158Set the minimum number of AIO threads to C<$nthreads>. The current
926default is C<8>, which means eight asynchronous operations can execute 1159default is C<8>, which means eight asynchronous operations can execute
927concurrently at any one time (the number of outstanding requests, 1160concurrently at any one time (the number of outstanding requests,
928however, is unlimited). 1161however, is unlimited).
929 1162
930IO::AIO starts threads only on demand, when an AIO request is queued and 1163IO::AIO starts threads only on demand, when an AIO request is queued and
931no free thread exists. 1164no free thread exists. Please note that queueing up a hundred requests can
1165create demand for a hundred threads, even if it turns out that everything
1166is in the cache and could have been processed faster by a single thread.
932 1167
933It is recommended to keep the number of threads relatively low, as some 1168It is recommended to keep the number of threads relatively low, as some
934Linux kernel versions will scale negatively with the number of threads 1169Linux kernel versions will scale negatively with the number of threads
935(higher parallelity => MUCH higher latency). With current Linux 2.6 1170(higher parallelity => MUCH higher latency). With current Linux 2.6
936versions, 4-32 threads should be fine. 1171versions, 4-32 threads should be fine.
… …
950This module automatically runs C<max_parallel 0> at program end, to ensure 1185This module automatically runs C<max_parallel 0> at program end, to ensure
951that all threads are killed and that there are no outstanding requests. 1186that all threads are killed and that there are no outstanding requests.
952 1187
953Under normal circumstances you don't need to call this function. 1188Under normal circumstances you don't need to call this function.
954 1189
1190=item IO::AIO::max_idle $nthreads
1191
1192Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1193threads that did not get a request to process within 10 seconds). That
1194means if a thread becomes idle while C<$nthreads> other threads are also
1195idle, it will free its resources and exit.
1196
1197This is useful when you allow a large number of threads (e.g. 100 or 1000)
1198to allow for extremely high load situations, but want to free resources
1199under normal circumstances (1000 threads can easily consume 30MB of RAM).
1200
1201The default is probably ok in most situations, especially if thread
1202creation is fast. If thread creation is very slow on your system you might
1203want to use larger values.
1204
955=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1205=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
956 1206
957This is a very bad function to use in interactive programs because it 1207This is a very bad function to use in interactive programs because it
958blocks, and a bad way to reduce concurrency because it is inexact: Better 1208blocks, and a bad way to reduce concurrency because it is inexact: Better
959use an C<aio_group> together with a feed callback. 1209use an C<aio_group> together with a feed callback.
960 1210
961Sets the maximum number of outstanding requests to C<$nreqs>. If you 1211Sets the maximum number of outstanding requests to C<$nreqs>. If you
962to queue up more than this number of requests, the next call to the 1212do queue up more than this number of requests, the next call to the
963C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) 1213C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
964function will block until the limit is no longer exceeded. 1214function will block until the limit is no longer exceeded.
965 1215
966The default value is very large, so there is no practical limit on the 1216The default value is very large, so there is no practical limit on the
967number of outstanding requests. 1217number of outstanding requests.
968 1218
969You can still queue as many requests as you want. Therefore, 1219You can still queue as many requests as you want. Therefore,
970C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1220C<max_oustsanding> is mainly useful in simple scripts (with low values) or
971as a stop gap to shield against fatal memory overflow (with large values). 1221as a stop gap to shield against fatal memory overflow (with large values).
1222
1223=back
1224
1225=head3 STATISTICAL INFORMATION
1226
1227=over
1228
1229=item IO::AIO::nreqs
1230
1231Returns the number of requests currently in the ready, execute or pending
1232states (i.e. for which their callback has not been invoked yet).
1233
1234Example: wait till there are no outstanding requests anymore:
1235
1236 IO::AIO::poll_wait, IO::AIO::poll_cb
1237 while IO::AIO::nreqs;
1238
1239=item IO::AIO::nready
1240
1241Returns the number of requests currently in the ready state (not yet
1242executed).
1243
1244=item IO::AIO::npending
1245
1246Returns the number of requests currently in the pending state (executed,
1247but not yet processed by poll_cb).
972 1248
973=back 1249=back
974 1250
975=cut 1251=cut
976 1252
… …
990 *$sym 1266 *$sym
991} 1267}
992 1268
993min_parallel 8; 1269min_parallel 8;
994 1270
995END { 1271END { flush }
996 flush;
997};
998 1272
9991; 12731;
1000 1274
1001=head2 FORK BEHAVIOUR 1275=head2 FORK BEHAVIOUR
1002 1276
… …
1022bytes of memory. In addition, stat requests need a stat buffer (possibly 1296bytes of memory. In addition, stat requests need a stat buffer (possibly
1023a few hundred bytes), readdir requires a result buffer and so on. Perl 1297a few hundred bytes), readdir requires a result buffer and so on. Perl
1024scalars and other data passed into aio requests will also be locked and 1298scalars and other data passed into aio requests will also be locked and
1025will consume memory till the request has entered the done state. 1299will consume memory till the request has entered the done state.
1026 1300
1027This is now awfully much, so queuing lots of requests is not usually a 1301This is not awfully much, so queuing lots of requests is not usually a
1028problem. 1302problem.
1029 1303
1030Per-thread usage: 1304Per-thread usage:
1031 1305
1032In the execution phase, some aio requests require more memory for 1306In the execution phase, some aio requests require more memory for

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