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Revision 1.85 by root, Sat Oct 28 01:40:30 2006 UTC vs.
Revision 1.108 by root, Fri Jun 1 13:25:50 2007 UTC

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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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61etc.), but can also be used to easily do operations in parallel that are 62etc.), but can also be used to easily do operations in parallel that are
62normally done sequentially, e.g. stat'ing many files, which is much faster 63normally done sequentially, e.g. stat'ing many files, which is much faster
63on a RAID volume or over NFS when you do a number of stat operations 64on a RAID volume or over NFS when you do a number of stat operations
64concurrently. 65concurrently.
65 66
66While this works on all types of file descriptors (for example sockets), 67While most of this works on all types of file descriptors (for
67using these functions on file descriptors that support nonblocking 68example sockets), using these functions on file descriptors that
68operation (again, sockets, pipes etc.) is very inefficient. Use an event 69support nonblocking operation (again, sockets, pipes etc.) is very
69loop for that (such as the L<Event|Event> module): IO::AIO will naturally 70inefficient. Use an event loop for that (such as the L<Event|Event>
70fit into such an event loop itself. 71module): IO::AIO will naturally fit into such an event loop itself.
71 72
72In this version, a number of threads are started that execute your 73In this version, a number of threads are started that execute your
73requests and signal their completion. You don't need thread support 74requests and signal their completion. You don't need thread support
74in 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
75to 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
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77not well-supported or restricted (GNU/Linux doesn't allow them on normal 78not well-supported or restricted (GNU/Linux doesn't allow them on normal
78files currently, for example), and they would only support aio_read and 79files currently, for example), and they would only support aio_read and
79aio_write, so the remaining functionality would have to be implemented 80aio_write, so the remaining functionality would have to be implemented
80using threads anyway. 81using threads anyway.
81 82
82Although the module will work with in the presence of other (Perl-) 83Although the module will work in the presence of other (Perl-) threads,
83threads, it is currently not reentrant in any way, so use appropriate 84it is currently not reentrant in any way, so use appropriate locking
84locking 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
85never 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;
86 131
87=head1 REQUEST ANATOMY AND LIFETIME 132=head1 REQUEST ANATOMY AND LIFETIME
88 133
89Every 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
90directly visible to Perl. 135directly visible to Perl.
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132Request 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
133(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
134aio 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
135result in a runtime error). 180result in a runtime error).
136 181
182=back
183
137=cut 184=cut
138 185
139package IO::AIO; 186package IO::AIO;
140 187
141no warnings; 188no warnings;
142use strict 'vars'; 189use strict 'vars';
143 190
144use base 'Exporter'; 191use base 'Exporter';
145 192
146BEGIN { 193BEGIN {
147 our $VERSION = '2.0'; 194 our $VERSION = '2.4';
148 195
149 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
150 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
151 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
199 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
152 aio_copy aio_group aio_nop aio_mknod); 200 aio_chown aio_chmod aio_utime);
153 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
154 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
155 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);
156 206
157 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 207 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
158 208
159 require XSLoader; 209 require XSLoader;
160 XSLoader::load ("IO::AIO", $VERSION); 210 XSLoader::load ("IO::AIO", $VERSION);
161} 211}
162 212
163=head1 FUNCTIONS 213=head1 FUNCTIONS
164 214
165=head2 AIO FUNCTIONS 215=head2 AIO REQUEST FUNCTIONS
166 216
167All the C<aio_*> calls are more or less thin wrappers around the syscall 217All the C<aio_*> calls are more or less thin wrappers around the syscall
168with the same name (sans C<aio_>). The arguments are similar or identical, 218with the same name (sans C<aio_>). The arguments are similar or identical,
169and they all accept an additional (and optional) C<$callback> argument 219and they all accept an additional (and optional) C<$callback> argument
170which 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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173syscall has been executed asynchronously. 223syscall has been executed asynchronously.
174 224
175All functions expecting a filehandle keep a copy of the filehandle 225All functions expecting a filehandle keep a copy of the filehandle
176internally until the request has finished. 226internally until the request has finished.
177 227
178All 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
179manipulation of those requests while they are in-flight. 229further manipulation of those requests while they are in-flight.
180 230
181The pathnames you pass to these routines I<must> be absolute and 231The pathnames you pass to these routines I<must> be absolute and
182encoded 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
183request is being executed, the current working directory could have 233request is being executed, the current working directory could have
184changed. Alternatively, you can make sure that you never change the 234changed. Alternatively, you can make sure that you never change the
185current working directory. 235current working directory anywhere in the program and then use relative
236paths.
186 237
187To encode pathnames to byte form, either make sure you either: a) 238To encode pathnames as octets, either make sure you either: a) always pass
188always pass in filenames you got from outside (command line, readdir 239in filenames you got from outside (command line, readdir etc.) without
189etc.), 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
190your 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
191environment, d) use Glib::filename_from_unicode on unicode filenames or e) 242environment, d) use Glib::filename_from_unicode on unicode filenames or e)
192use 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.
193 247
194=over 4 248=over 4
195 249
196=item $prev_pri = aioreq_pri [$pri] 250=item $prev_pri = aioreq_pri [$pri]
197 251
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217 aio_read $_[0], ..., sub { 271 aio_read $_[0], ..., sub {
218 ... 272 ...
219 }; 273 };
220 }; 274 };
221 275
276
222=item aioreq_nice $pri_adjust 277=item aioreq_nice $pri_adjust
223 278
224Similar 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
225priority, so effects are cumulative. 280priority, so the effect is cumulative.
281
226 282
227=item aio_open $pathname, $flags, $mode, $callback->($fh) 283=item aio_open $pathname, $flags, $mode, $callback->($fh)
228 284
229Asynchronously 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
230created filehandle for the file. 286created filehandle for the file.
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236list. They are the same as used by C<sysopen>. 292list. They are the same as used by C<sysopen>.
237 293
238Likewise, 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
239didn'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>,
240except 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,
241and C<0666> or C<0777> if you do). 297and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
298by the umask in effect then the request is being executed, so better never
299change the umask.
242 300
243Example: 301Example:
244 302
245 aio_open "/etc/passwd", O_RDONLY, 0, sub { 303 aio_open "/etc/passwd", O_RDONLY, 0, sub {
246 if ($_[0]) { 304 if ($_[0]) {
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249 } else { 307 } else {
250 die "open failed: $!\n"; 308 die "open failed: $!\n";
251 } 309 }
252 }; 310 };
253 311
312
254=item aio_close $fh, $callback->($status) 313=item aio_close $fh, $callback->($status)
255 314
256Asynchronously close a file and call the callback with the result 315Asynchronously close a file and call the callback with the result
257code. I<WARNING:> although accepted, you should not pass in a perl 316code. I<WARNING:> although accepted, you should not pass in a perl
258filehandle 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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260C<close> or just let filehandles go out of scope. 319C<close> or just let filehandles go out of scope.
261 320
262This 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
263therefore best to avoid this function. 322therefore best to avoid this function.
264 323
324
265=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 325=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
266 326
267=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 327=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
268 328
269Reads 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>
270into 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
271callback 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
272like the syscall). 332like the syscall). If C<offset> is undefined, then the current file offset
333will be used (and updated), otherwise the file offset will not be changed
334by these calls.
273 335
274The C<$data> scalar I<MUST NOT> be modified in any way while the request 336The C<$data> scalar I<MUST NOT> be modified in any way while the request
275is outstanding. Modifying it can result in segfaults or WW3 (if the 337is outstanding. Modifying it can result in segfaults or World War III (if
276necessary/optional hardware is installed). 338the necessary/optional hardware is installed).
277 339
278Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 340Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
279offset C<0> within the scalar: 341offset C<0> within the scalar:
280 342
281 aio_read $fh, 7, 15, $buffer, 0, sub { 343 aio_read $fh, 7, 15, $buffer, 0, sub {
282 $_[0] > 0 or die "read error: $!"; 344 $_[0] > 0 or die "read error: $!";
283 print "read $_[0] bytes: <$buffer>\n"; 345 print "read $_[0] bytes: <$buffer>\n";
284 }; 346 };
347
285 348
286=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 349=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
287 350
288Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 351Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
289reading at byte offset C<$in_offset>, and starts writing at the current 352reading at byte offset C<$in_offset>, and starts writing at the current
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303C<$in_fh> than are written, and there is no way to find out how many 366C<$in_fh> than are written, and there is no way to find out how many
304bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 367bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
305provides the number of bytes written to C<$out_fh>. Only if the result 368provides the number of bytes written to C<$out_fh>. Only if the result
306value equals C<$length> one can assume that C<$length> bytes have been 369value equals C<$length> one can assume that C<$length> bytes have been
307read. 370read.
371
308 372
309=item aio_readahead $fh,$offset,$length, $callback->($retval) 373=item aio_readahead $fh,$offset,$length, $callback->($retval)
310 374
311C<aio_readahead> populates the page cache with data from a file so that 375C<aio_readahead> populates the page cache with data from a file so that
312subsequent reads from that file will not block on disk I/O. The C<$offset> 376subsequent reads from that file will not block on disk I/O. The C<$offset>
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318file. The current file offset of the file is left unchanged. 382file. The current file offset of the file is left unchanged.
319 383
320If that syscall doesn't exist (likely if your OS isn't Linux) it will be 384If that syscall doesn't exist (likely if your OS isn't Linux) it will be
321emulated by simply reading the data, which would have a similar effect. 385emulated by simply reading the data, which would have a similar effect.
322 386
387
323=item aio_stat $fh_or_path, $callback->($status) 388=item aio_stat $fh_or_path, $callback->($status)
324 389
325=item aio_lstat $fh, $callback->($status) 390=item aio_lstat $fh, $callback->($status)
326 391
327Works like perl's C<stat> or C<lstat> in void context. The callback will 392Works like perl's C<stat> or C<lstat> in void context. The callback will
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340 aio_stat "/etc/passwd", sub { 405 aio_stat "/etc/passwd", sub {
341 $_[0] and die "stat failed: $!"; 406 $_[0] and die "stat failed: $!";
342 print "size is ", -s _, "\n"; 407 print "size is ", -s _, "\n";
343 }; 408 };
344 409
410
411=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
412
413Works like perl's C<utime> function (including the special case of $atime
414and $mtime being undef). Fractional times are supported if the underlying
415syscalls support them.
416
417When called with a pathname, uses utimes(2) if available, otherwise
418utime(2). If called on a file descriptor, uses futimes(2) if available,
419otherwise returns ENOSYS, so this is not portable.
420
421Examples:
422
423 # set atime and mtime to current time (basically touch(1)):
424 aio_utime "path", undef, undef;
425 # set atime to current time and mtime to beginning of the epoch:
426 aio_utime "path", time, undef; # undef==0
427
428
429=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
430
431Works like perl's C<chown> function, except that C<undef> for either $uid
432or $gid is being interpreted as "do not change" (but -1 can also be used).
433
434Examples:
435
436 # same as "chown root path" in the shell:
437 aio_chown "path", 0, -1;
438 # same as above:
439 aio_chown "path", 0, undef;
440
441
442=item aio_chmod $fh_or_path, $mode, $callback->($status)
443
444Works like perl's C<chmod> function.
445
446
345=item aio_unlink $pathname, $callback->($status) 447=item aio_unlink $pathname, $callback->($status)
346 448
347Asynchronously unlink (delete) a file and call the callback with the 449Asynchronously unlink (delete) a file and call the callback with the
348result code. 450result code.
349 451
452
350=item aio_mknod $path, $mode, $dev, $callback->($status) 453=item aio_mknod $path, $mode, $dev, $callback->($status)
351 454
455[EXPERIMENTAL]
456
352Asynchronously create a device node (or fifo). See mknod(2). 457Asynchronously create a device node (or fifo). See mknod(2).
353 458
354The only portable (POSIX) way of calling this function is: 459The only (POSIX-) portable way of calling this function is:
355 460
356 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 461 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
462
357 463
358=item aio_link $srcpath, $dstpath, $callback->($status) 464=item aio_link $srcpath, $dstpath, $callback->($status)
359 465
360Asynchronously create a new link to the existing object at C<$srcpath> at 466Asynchronously create a new link to the existing object at C<$srcpath> at
361the path C<$dstpath> and call the callback with the result code. 467the path C<$dstpath> and call the callback with the result code.
362 468
469
363=item aio_symlink $srcpath, $dstpath, $callback->($status) 470=item aio_symlink $srcpath, $dstpath, $callback->($status)
364 471
365Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 472Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
366the path C<$dstpath> and call the callback with the result code. 473the path C<$dstpath> and call the callback with the result code.
367 474
475
476=item aio_readlink $path, $callback->($link)
477
478Asynchronously read the symlink specified by C<$path> and pass it to
479the callback. If an error occurs, nothing or undef gets passed to the
480callback.
481
482
368=item aio_rename $srcpath, $dstpath, $callback->($status) 483=item aio_rename $srcpath, $dstpath, $callback->($status)
369 484
370Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 485Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
371rename(2) and call the callback with the result code. 486rename(2) and call the callback with the result code.
372 487
488
489=item aio_mkdir $pathname, $mode, $callback->($status)
490
491Asynchronously mkdir (create) a directory and call the callback with
492the result code. C<$mode> will be modified by the umask at the time the
493request is executed, so do not change your umask.
494
495
373=item aio_rmdir $pathname, $callback->($status) 496=item aio_rmdir $pathname, $callback->($status)
374 497
375Asynchronously rmdir (delete) a directory and call the callback with the 498Asynchronously rmdir (delete) a directory and call the callback with the
376result code. 499result code.
500
377 501
378=item aio_readdir $pathname, $callback->($entries) 502=item aio_readdir $pathname, $callback->($entries)
379 503
380Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 504Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
381directory (i.e. opendir + readdir + closedir). The entries will not be 505directory (i.e. opendir + readdir + closedir). The entries will not be
382sorted, and will B<NOT> include the C<.> and C<..> entries. 506sorted, and will B<NOT> include the C<.> and C<..> entries.
383 507
384The callback a single argument which is either C<undef> or an array-ref 508The callback a single argument which is either C<undef> or an array-ref
385with the filenames. 509with the filenames.
510
511
512=item aio_load $path, $data, $callback->($status)
513
514This is a composite request that tries to fully load the given file into
515memory. Status is the same as with aio_read.
516
517=cut
518
519sub aio_load($$;$) {
520 aio_block {
521 my ($path, undef, $cb) = @_;
522 my $data = \$_[1];
523
524 my $pri = aioreq_pri;
525 my $grp = aio_group $cb;
526
527 aioreq_pri $pri;
528 add $grp aio_open $path, O_RDONLY, 0, sub {
529 my $fh = shift
530 or return $grp->result (-1);
531
532 aioreq_pri $pri;
533 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
534 $grp->result ($_[0]);
535 };
536 };
537
538 $grp
539 }
540}
386 541
387=item aio_copy $srcpath, $dstpath, $callback->($status) 542=item aio_copy $srcpath, $dstpath, $callback->($status)
388 543
389Try to copy the I<file> (directories not supported as either source or 544Try to copy the I<file> (directories not supported as either source or
390destination) from C<$srcpath> to C<$dstpath> and call the callback with 545destination) from C<$srcpath> to C<$dstpath> and call the callback with
… …
400errors are being ignored. 555errors are being ignored.
401 556
402=cut 557=cut
403 558
404sub aio_copy($$;$) { 559sub aio_copy($$;$) {
560 aio_block {
405 my ($src, $dst, $cb) = @_; 561 my ($src, $dst, $cb) = @_;
406 562
407 my $pri = aioreq_pri; 563 my $pri = aioreq_pri;
408 my $grp = aio_group $cb; 564 my $grp = aio_group $cb;
409 565
410 aioreq_pri $pri; 566 aioreq_pri $pri;
411 add $grp aio_open $src, O_RDONLY, 0, sub { 567 add $grp aio_open $src, O_RDONLY, 0, sub {
412 if (my $src_fh = $_[0]) { 568 if (my $src_fh = $_[0]) {
413 my @stat = stat $src_fh; 569 my @stat = stat $src_fh;
414 570
415 aioreq_pri $pri; 571 aioreq_pri $pri;
416 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 572 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
417 if (my $dst_fh = $_[0]) { 573 if (my $dst_fh = $_[0]) {
418 aioreq_pri $pri; 574 aioreq_pri $pri;
419 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 575 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
420 if ($_[0] == $stat[7]) { 576 if ($_[0] == $stat[7]) {
421 $grp->result (0); 577 $grp->result (0);
422 close $src_fh; 578 close $src_fh;
423 579
424 # those should not normally block. should. should. 580 # those should not normally block. should. should.
425 utime $stat[8], $stat[9], $dst; 581 utime $stat[8], $stat[9], $dst;
426 chmod $stat[2] & 07777, $dst_fh; 582 chmod $stat[2] & 07777, $dst_fh;
427 chown $stat[4], $stat[5], $dst_fh; 583 chown $stat[4], $stat[5], $dst_fh;
428 close $dst_fh; 584 close $dst_fh;
429 } else { 585 } else {
430 $grp->result (-1); 586 $grp->result (-1);
431 close $src_fh; 587 close $src_fh;
432 close $dst_fh; 588 close $dst_fh;
433 589
434 aioreq $pri; 590 aioreq $pri;
435 add $grp aio_unlink $dst; 591 add $grp aio_unlink $dst;
592 }
436 } 593 };
594 } else {
595 $grp->result (-1);
437 }; 596 }
438 } else {
439 $grp->result (-1);
440 } 597 },
598
599 } else {
600 $grp->result (-1);
441 }, 601 }
442
443 } else {
444 $grp->result (-1);
445 } 602 };
603
604 $grp
446 }; 605 }
447
448 $grp
449} 606}
450 607
451=item aio_move $srcpath, $dstpath, $callback->($status) 608=item aio_move $srcpath, $dstpath, $callback->($status)
452 609
453Try to move the I<file> (directories not supported as either source or 610Try to move the I<file> (directories not supported as either source or
… …
459that is successful, unlinking the C<$srcpath>. 616that is successful, unlinking the C<$srcpath>.
460 617
461=cut 618=cut
462 619
463sub aio_move($$;$) { 620sub aio_move($$;$) {
621 aio_block {
464 my ($src, $dst, $cb) = @_; 622 my ($src, $dst, $cb) = @_;
465 623
466 my $pri = aioreq_pri; 624 my $pri = aioreq_pri;
467 my $grp = aio_group $cb; 625 my $grp = aio_group $cb;
468 626
469 aioreq_pri $pri; 627 aioreq_pri $pri;
470 add $grp aio_rename $src, $dst, sub { 628 add $grp aio_rename $src, $dst, sub {
471 if ($_[0] && $! == EXDEV) { 629 if ($_[0] && $! == EXDEV) {
472 aioreq_pri $pri; 630 aioreq_pri $pri;
473 add $grp aio_copy $src, $dst, sub { 631 add $grp aio_copy $src, $dst, sub {
632 $grp->result ($_[0]);
633
634 if (!$_[0]) {
635 aioreq_pri $pri;
636 add $grp aio_unlink $src;
637 }
638 };
639 } else {
474 $grp->result ($_[0]); 640 $grp->result ($_[0]);
475
476 if (!$_[0]) {
477 aioreq_pri $pri;
478 add $grp aio_unlink $src;
479 }
480 }; 641 }
481 } else {
482 $grp->result ($_[0]);
483 } 642 };
643
644 $grp
484 }; 645 }
485
486 $grp
487} 646}
488 647
489=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 648=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
490 649
491Scans a directory (similar to C<aio_readdir>) but additionally tries to 650Scans a directory (similar to C<aio_readdir>) but additionally tries to
… …
538as those tend to return 0 or 1 as link counts, which disables the 697as those tend to return 0 or 1 as link counts, which disables the
539directory counting heuristic. 698directory counting heuristic.
540 699
541=cut 700=cut
542 701
543sub aio_scandir($$$) { 702sub aio_scandir($$;$) {
703 aio_block {
544 my ($path, $maxreq, $cb) = @_; 704 my ($path, $maxreq, $cb) = @_;
545 705
546 my $pri = aioreq_pri; 706 my $pri = aioreq_pri;
547 707
548 my $grp = aio_group $cb; 708 my $grp = aio_group $cb;
549 709
550 $maxreq = 4 if $maxreq <= 0; 710 $maxreq = 4 if $maxreq <= 0;
551 711
552 # stat once 712 # stat once
553 aioreq_pri $pri;
554 add $grp aio_stat $path, sub {
555 return $grp->result () if $_[0];
556 my $now = time;
557 my $hash1 = join ":", (stat _)[0,1,3,7,9];
558
559 # read the directory entries
560 aioreq_pri $pri; 713 aioreq_pri $pri;
561 add $grp aio_readdir $path, sub { 714 add $grp aio_stat $path, sub {
562 my $entries = shift
563 or return $grp->result (); 715 return $grp->result () if $_[0];
716 my $now = time;
717 my $hash1 = join ":", (stat _)[0,1,3,7,9];
564 718
565 # stat the dir another time 719 # read the directory entries
566 aioreq_pri $pri; 720 aioreq_pri $pri;
721 add $grp aio_readdir $path, sub {
722 my $entries = shift
723 or return $grp->result ();
724
725 # stat the dir another time
726 aioreq_pri $pri;
567 add $grp aio_stat $path, sub { 727 add $grp aio_stat $path, sub {
568 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 728 my $hash2 = join ":", (stat _)[0,1,3,7,9];
569 729
570 my $ndirs; 730 my $ndirs;
571 731
572 # take the slow route if anything looks fishy 732 # take the slow route if anything looks fishy
573 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 733 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
574 $ndirs = -1; 734 $ndirs = -1;
575 } else { 735 } else {
576 # if nlink == 2, we are finished 736 # if nlink == 2, we are finished
577 # on non-posix-fs's, we rely on nlink < 2 737 # on non-posix-fs's, we rely on nlink < 2
578 $ndirs = (stat _)[3] - 2 738 $ndirs = (stat _)[3] - 2
579 or return $grp->result ([], $entries); 739 or return $grp->result ([], $entries);
580 } 740 }
581 741
582 # sort into likely dirs and likely nondirs 742 # sort into likely dirs and likely nondirs
583 # dirs == files without ".", short entries first 743 # dirs == files without ".", short entries first
584 $entries = [map $_->[0], 744 $entries = [map $_->[0],
585 sort { $b->[1] cmp $a->[1] } 745 sort { $b->[1] cmp $a->[1] }
586 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 746 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
587 @$entries]; 747 @$entries];
588 748
589 my (@dirs, @nondirs); 749 my (@dirs, @nondirs);
590 750
591 my $statgrp = add $grp aio_group sub { 751 my $statgrp = add $grp aio_group sub {
592 $grp->result (\@dirs, \@nondirs); 752 $grp->result (\@dirs, \@nondirs);
593 }; 753 };
594 754
595 limit $statgrp $maxreq; 755 limit $statgrp $maxreq;
596 feed $statgrp sub { 756 feed $statgrp sub {
597 return unless @$entries; 757 return unless @$entries;
598 my $entry = pop @$entries; 758 my $entry = pop @$entries;
599 759
600 aioreq_pri $pri; 760 aioreq_pri $pri;
601 add $statgrp aio_stat "$path/$entry/.", sub { 761 add $statgrp aio_stat "$path/$entry/.", sub {
602 if ($_[0] < 0) { 762 if ($_[0] < 0) {
603 push @nondirs, $entry; 763 push @nondirs, $entry;
604 } else { 764 } else {
605 # need to check for real directory 765 # need to check for real directory
606 aioreq_pri $pri; 766 aioreq_pri $pri;
607 add $statgrp aio_lstat "$path/$entry", sub { 767 add $statgrp aio_lstat "$path/$entry", sub {
608 if (-d _) { 768 if (-d _) {
609 push @dirs, $entry; 769 push @dirs, $entry;
610 770
611 unless (--$ndirs) { 771 unless (--$ndirs) {
612 push @nondirs, @$entries; 772 push @nondirs, @$entries;
613 feed $statgrp; 773 feed $statgrp;
774 }
775 } else {
776 push @nondirs, $entry;
614 } 777 }
615 } else {
616 push @nondirs, $entry;
617 } 778 }
618 } 779 }
619 } 780 };
620 }; 781 };
621 }; 782 };
622 }; 783 };
623 }; 784 };
785
786 $grp
624 }; 787 }
788}
625 789
790=item aio_rmtree $path, $callback->($status)
791
792Delete a directory tree starting (and including) C<$path>, return the
793status of the final C<rmdir> only. This is a composite request that
794uses C<aio_scandir> to recurse into and rmdir directories, and unlink
795everything else.
796
797=cut
798
799sub aio_rmtree;
800sub aio_rmtree($;$) {
801 aio_block {
802 my ($path, $cb) = @_;
803
804 my $pri = aioreq_pri;
805 my $grp = aio_group $cb;
806
807 aioreq_pri $pri;
808 add $grp aio_scandir $path, 0, sub {
809 my ($dirs, $nondirs) = @_;
810
811 my $dirgrp = aio_group sub {
812 add $grp aio_rmdir $path, sub {
813 $grp->result ($_[0]);
814 };
815 };
816
817 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
818 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
819
820 add $grp $dirgrp;
821 };
822
626 $grp 823 $grp
824 }
627} 825}
628 826
629=item aio_fsync $fh, $callback->($status) 827=item aio_fsync $fh, $callback->($status)
630 828
631Asynchronously call fsync on the given filehandle and call the callback 829Asynchronously call fsync on the given filehandle and call the callback
… …
845 1043
846=back 1044=back
847 1045
848=head2 SUPPORT FUNCTIONS 1046=head2 SUPPORT FUNCTIONS
849 1047
1048=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1049
850=over 4 1050=over 4
851 1051
852=item $fileno = IO::AIO::poll_fileno 1052=item $fileno = IO::AIO::poll_fileno
853 1053
854Return the I<request result pipe file descriptor>. This filehandle must be 1054Return the I<request result pipe file descriptor>. This filehandle must be
… …
858 1058
859See C<poll_cb> for an example. 1059See C<poll_cb> for an example.
860 1060
861=item IO::AIO::poll_cb 1061=item IO::AIO::poll_cb
862 1062
863Process all outstanding events on the result pipe. You have to call this 1063Process some outstanding events on the result pipe. You have to call this
864regularly. Returns the number of events processed. Returns immediately 1064regularly. Returns the number of events processed. Returns immediately
865when no events are outstanding. 1065when no events are outstanding. The amount of events processed depends on
1066the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
866 1067
867If not all requests were processed for whatever reason, the filehandle 1068If not all requests were processed for whatever reason, the filehandle
868will still be ready when C<poll_cb> returns. 1069will still be ready when C<poll_cb> returns.
869 1070
870Example: Install an Event watcher that automatically calls 1071Example: Install an Event watcher that automatically calls
… …
872 1073
873 Event->io (fd => IO::AIO::poll_fileno, 1074 Event->io (fd => IO::AIO::poll_fileno,
874 poll => 'r', async => 1, 1075 poll => 'r', async => 1,
875 cb => \&IO::AIO::poll_cb); 1076 cb => \&IO::AIO::poll_cb);
876 1077
877=item IO::AIO::poll_some $max_requests 1078=item IO::AIO::max_poll_reqs $nreqs
878 1079
879Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1080=item IO::AIO::max_poll_time $seconds
880at a time.
881 1081
882Useful if you want to ensure some level of interactiveness when perl is 1082These set the maximum number of requests (default C<0>, meaning infinity)
883not fast enough to process all requests in time. 1083that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1084the maximum amount of time (default C<0>, meaning infinity) spent in
1085C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1086of time C<poll_cb> is allowed to use).
1087
1088Setting C<max_poll_time> to a non-zero value creates an overhead of one
1089syscall per request processed, which is not normally a problem unless your
1090callbacks are really really fast or your OS is really really slow (I am
1091not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1092
1093Setting these is useful if you want to ensure some level of
1094interactiveness when perl is not fast enough to process all requests in
1095time.
1096
1097For interactive programs, values such as C<0.01> to C<0.1> should be fine.
884 1098
885Example: Install an Event watcher that automatically calls 1099Example: Install an Event watcher that automatically calls
886IO::AIO::poll_some with low priority, to ensure that other parts of the 1100IO::AIO::poll_cb with low priority, to ensure that other parts of the
887program get the CPU sometimes even under high AIO load. 1101program get the CPU sometimes even under high AIO load.
888 1102
1103 # try not to spend much more than 0.1s in poll_cb
1104 IO::AIO::max_poll_time 0.1;
1105
1106 # use a low priority so other tasks have priority
889 Event->io (fd => IO::AIO::poll_fileno, 1107 Event->io (fd => IO::AIO::poll_fileno,
890 poll => 'r', nice => 1, 1108 poll => 'r', nice => 1,
891 cb => sub { IO::AIO::poll_some 256 }); 1109 cb => &IO::AIO::poll_cb);
892 1110
893=item IO::AIO::poll_wait 1111=item IO::AIO::poll_wait
894 1112
1113If there are any outstanding requests and none of them in the result
895Wait till the result filehandle becomes ready for reading (simply does a 1114phase, wait till the result filehandle becomes ready for reading (simply
896C<select> on the filehandle. This is useful if you want to synchronously wait 1115does a C<select> on the filehandle. This is useful if you want to
897for some requests to finish). 1116synchronously wait for some requests to finish).
898 1117
899See C<nreqs> for an example. 1118See C<nreqs> for an example.
900 1119
1120=item IO::AIO::poll
1121
1122Waits until some requests have been handled.
1123
1124Returns the number of requests processed, but is otherwise strictly
1125equivalent to:
1126
1127 IO::AIO::poll_wait, IO::AIO::poll_cb
1128
901=item IO::AIO::nreqs 1129=item IO::AIO::flush
902 1130
903Returns the number of requests currently in the ready, execute or pending 1131Wait till all outstanding AIO requests have been handled.
904states (i.e. for which their callback has not been invoked yet).
905 1132
906Example: wait till there are no outstanding requests anymore: 1133Strictly equivalent to:
907 1134
908 IO::AIO::poll_wait, IO::AIO::poll_cb 1135 IO::AIO::poll_wait, IO::AIO::poll_cb
909 while IO::AIO::nreqs; 1136 while IO::AIO::nreqs;
910 1137
911=item IO::AIO::nready 1138=back
912 1139
913Returns the number of requests currently in the ready state (not yet 1140=head3 CONTROLLING THE NUMBER OF THREADS
914executed).
915 1141
916=item IO::AIO::npending 1142=over
917
918Returns the number of requests currently in the pending state (executed,
919but not yet processed by poll_cb).
920
921=item IO::AIO::flush
922
923Wait till all outstanding AIO requests have been handled.
924
925Strictly equivalent to:
926
927 IO::AIO::poll_wait, IO::AIO::poll_cb
928 while IO::AIO::nreqs;
929
930=item IO::AIO::poll
931
932Waits until some requests have been handled.
933
934Strictly equivalent to:
935
936 IO::AIO::poll_wait, IO::AIO::poll_cb
937 if IO::AIO::nreqs;
938 1143
939=item IO::AIO::min_parallel $nthreads 1144=item IO::AIO::min_parallel $nthreads
940 1145
941Set the minimum number of AIO threads to C<$nthreads>. The current 1146Set the minimum number of AIO threads to C<$nthreads>. The current
942default is C<8>, which means eight asynchronous operations can execute 1147default is C<8>, which means eight asynchronous operations can execute
943concurrently at any one time (the number of outstanding requests, 1148concurrently at any one time (the number of outstanding requests,
944however, is unlimited). 1149however, is unlimited).
945 1150
946IO::AIO starts threads only on demand, when an AIO request is queued and 1151IO::AIO starts threads only on demand, when an AIO request is queued and
947no free thread exists. 1152no free thread exists. Please note that queueing up a hundred requests can
1153create demand for a hundred threads, even if it turns out that everything
1154is in the cache and could have been processed faster by a single thread.
948 1155
949It is recommended to keep the number of threads relatively low, as some 1156It is recommended to keep the number of threads relatively low, as some
950Linux kernel versions will scale negatively with the number of threads 1157Linux kernel versions will scale negatively with the number of threads
951(higher parallelity => MUCH higher latency). With current Linux 2.6 1158(higher parallelity => MUCH higher latency). With current Linux 2.6
952versions, 4-32 threads should be fine. 1159versions, 4-32 threads should be fine.
… …
966This module automatically runs C<max_parallel 0> at program end, to ensure 1173This module automatically runs C<max_parallel 0> at program end, to ensure
967that all threads are killed and that there are no outstanding requests. 1174that all threads are killed and that there are no outstanding requests.
968 1175
969Under normal circumstances you don't need to call this function. 1176Under normal circumstances you don't need to call this function.
970 1177
1178=item IO::AIO::max_idle $nthreads
1179
1180Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1181threads that did not get a request to process within 10 seconds). That
1182means if a thread becomes idle while C<$nthreads> other threads are also
1183idle, it will free its resources and exit.
1184
1185This is useful when you allow a large number of threads (e.g. 100 or 1000)
1186to allow for extremely high load situations, but want to free resources
1187under normal circumstances (1000 threads can easily consume 30MB of RAM).
1188
1189The default is probably ok in most situations, especially if thread
1190creation is fast. If thread creation is very slow on your system you might
1191want to use larger values.
1192
971=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1193=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
972 1194
973This is a very bad function to use in interactive programs because it 1195This is a very bad function to use in interactive programs because it
974blocks, and a bad way to reduce concurrency because it is inexact: Better 1196blocks, and a bad way to reduce concurrency because it is inexact: Better
975use an C<aio_group> together with a feed callback. 1197use an C<aio_group> together with a feed callback.
… …
986C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1208C<max_oustsanding> is mainly useful in simple scripts (with low values) or
987as a stop gap to shield against fatal memory overflow (with large values). 1209as a stop gap to shield against fatal memory overflow (with large values).
988 1210
989=back 1211=back
990 1212
1213=head3 STATISTICAL INFORMATION
1214
1215=over
1216
1217=item IO::AIO::nreqs
1218
1219Returns the number of requests currently in the ready, execute or pending
1220states (i.e. for which their callback has not been invoked yet).
1221
1222Example: wait till there are no outstanding requests anymore:
1223
1224 IO::AIO::poll_wait, IO::AIO::poll_cb
1225 while IO::AIO::nreqs;
1226
1227=item IO::AIO::nready
1228
1229Returns the number of requests currently in the ready state (not yet
1230executed).
1231
1232=item IO::AIO::npending
1233
1234Returns the number of requests currently in the pending state (executed,
1235but not yet processed by poll_cb).
1236
1237=back
1238
991=cut 1239=cut
992 1240
993# support function to convert a fd into a perl filehandle 1241# support function to convert a fd into a perl filehandle
994sub _fd2fh { 1242sub _fd2fh {
995 return undef if $_[0] < 0; 1243 return undef if $_[0] < 0;
… …
1006 *$sym 1254 *$sym
1007} 1255}
1008 1256
1009min_parallel 8; 1257min_parallel 8;
1010 1258
1011END { 1259END { flush }
1012 min_parallel 1;
1013 flush;
1014};
1015 1260
10161; 12611;
1017 1262
1018=head2 FORK BEHAVIOUR 1263=head2 FORK BEHAVIOUR
1019 1264

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