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Revision 1.109 by root, Sun Jun 3 09:44:17 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
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_group aio_nop); 199 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
200 aio_chown aio_chmod aio_utime);
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 203 min_parallel max_parallel max_idle
204 nreqs nready npending nthreads
205 max_poll_time max_poll_reqs);
140 206
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 207 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 208
143 require XSLoader; 209 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 210 XSLoader::load ("IO::AIO", $VERSION);
145} 211}
146 212
147=head1 FUNCTIONS 213=head1 FUNCTIONS
148 214
149=head2 AIO FUNCTIONS 215=head2 AIO REQUEST FUNCTIONS
150 216
151All the C<aio_*> calls are more or less thin wrappers around the syscall 217All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 218with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 219and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 220which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 223syscall has been executed asynchronously.
158 224
159All functions expecting a filehandle keep a copy of the filehandle 225All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 226internally until the request has finished.
161 227
162All requests return objects of type L<IO::AIO::REQ> that allow further 228All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 229further manipulation of those requests while they are in-flight.
164 230
165The pathnames you pass to these routines I<must> be absolute and 231The pathnames you pass to these routines I<must> be absolute and
166encoded in byte form. The reason for the former is that at the time the 232encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 233request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 234changed. Alternatively, you can make sure that you never change the
169current working directory. 235current working directory anywhere in the program and then use relative
236paths.
170 237
171To encode pathnames to byte form, either make sure you either: a) 238To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 239in filenames you got from outside (command line, readdir etc.) without
173etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode 240tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174your pathnames to the locale (or other) encoding in effect in the user 241your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 242environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 243use something else to ensure your scalar has the correct contents.
244
245This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246handles correctly wether it is set or not.
177 247
178=over 4 248=over 4
179 249
180=item $prev_pri = aioreq_pri [$pri] 250=item $prev_pri = aioreq_pri [$pri]
181 251
… …
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.
… …
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]) {
… …
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
… …
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 offset will be used (and
335updated), otherwise the file offset will not be changed by these calls.
336
337If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
338
339If C<$dataoffset> is less than zero, it will be counted from the end of
340C<$data>.
341
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 342The C<$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 343is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 344the necessary/optional hardware is installed).
261 345
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 346Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 347offset C<0> within the scalar:
264 348
265 aio_read $fh, 7, 15, $buffer, 0, sub { 349 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 350 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 351 print "read $_[0] bytes: <$buffer>\n";
268 }; 352 };
269 353
270=item aio_move $srcpath, $dstpath, $callback->($status)
271
272Try to move the I<file> (directories not supported as either source or
273destination) from C<$srcpath> to C<$dstpath> and call the callback with
274the C<0> (error) or C<-1> ok.
275
276This is a composite request that tries to rename(2) the file first. If
277rename files with C<EXDEV>, it creates the destination file with mode 0200
278and copies the contents of the source file into it using C<aio_sendfile>,
279followed by restoring atime, mtime, access mode and uid/gid, in that
280order, and unlinking the C<$srcpath>.
281
282If an error occurs, the partial destination file will be unlinked, if
283possible, except when setting atime, mtime, access mode and uid/gid, where
284errors are being ignored.
285
286=cut
287
288sub aio_move($$$) {
289 my ($src, $dst, $cb) = @_;
290
291 my $pri = aioreq_pri;
292 my $grp = aio_group $cb;
293
294 aioreq_pri $pri;
295 add $grp aio_rename $src, $dst, sub {
296 if ($_[0] && $! == EXDEV) {
297 aioreq_pri $pri;
298 add $grp aio_open $src, O_RDONLY, 0, sub {
299 if (my $src_fh = $_[0]) {
300 my @stat = stat $src_fh;
301
302 aioreq_pri $pri;
303 add $grp aio_open $dst, O_WRONLY, 0200, sub {
304 if (my $dst_fh = $_[0]) {
305 aioreq_pri $pri;
306 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
307 close $src_fh;
308
309 if ($_[0] == $stat[7]) {
310 utime $stat[8], $stat[9], $dst;
311 chmod $stat[2] & 07777, $dst_fh;
312 chown $stat[4], $stat[5], $dst_fh;
313 close $dst_fh;
314
315 aioreq_pri $pri;
316 add $grp aio_unlink $src, sub {
317 $grp->result ($_[0]);
318 };
319 } else {
320 my $errno = $!;
321 aioreq_pri $pri;
322 add $grp aio_unlink $dst, sub {
323 $! = $errno;
324 $grp->result (-1);
325 };
326 }
327 };
328 } else {
329 $grp->result (-1);
330 }
331 },
332
333 } else {
334 $grp->result (-1);
335 }
336 };
337 } else {
338 $grp->result ($_[0]);
339 }
340 };
341
342 $grp
343}
344 354
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 355=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 356
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 357Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
348reading at byte offset C<$in_offset>, and starts writing at the current 358reading at byte offset C<$in_offset>, and starts writing at the current
… …
362C<$in_fh> than are written, and there is no way to find out how many 372C<$in_fh> than are written, and there is no way to find out how many
363bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 373bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
364provides the number of bytes written to C<$out_fh>. Only if the result 374provides the number of bytes written to C<$out_fh>. Only if the result
365value equals C<$length> one can assume that C<$length> bytes have been 375value equals C<$length> one can assume that C<$length> bytes have been
366read. 376read.
377
367 378
368=item aio_readahead $fh,$offset,$length, $callback->($retval) 379=item aio_readahead $fh,$offset,$length, $callback->($retval)
369 380
370C<aio_readahead> populates the page cache with data from a file so that 381C<aio_readahead> populates the page cache with data from a file so that
371subsequent reads from that file will not block on disk I/O. The C<$offset> 382subsequent reads from that file will not block on disk I/O. The C<$offset>
… …
377file. The current file offset of the file is left unchanged. 388file. The current file offset of the file is left unchanged.
378 389
379If that syscall doesn't exist (likely if your OS isn't Linux) it will be 390If that syscall doesn't exist (likely if your OS isn't Linux) it will be
380emulated by simply reading the data, which would have a similar effect. 391emulated by simply reading the data, which would have a similar effect.
381 392
393
382=item aio_stat $fh_or_path, $callback->($status) 394=item aio_stat $fh_or_path, $callback->($status)
383 395
384=item aio_lstat $fh, $callback->($status) 396=item aio_lstat $fh, $callback->($status)
385 397
386Works like perl's C<stat> or C<lstat> in void context. The callback will 398Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
399 aio_stat "/etc/passwd", sub { 411 aio_stat "/etc/passwd", sub {
400 $_[0] and die "stat failed: $!"; 412 $_[0] and die "stat failed: $!";
401 print "size is ", -s _, "\n"; 413 print "size is ", -s _, "\n";
402 }; 414 };
403 415
416
417=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
418
419Works like perl's C<utime> function (including the special case of $atime
420and $mtime being undef). Fractional times are supported if the underlying
421syscalls support them.
422
423When called with a pathname, uses utimes(2) if available, otherwise
424utime(2). If called on a file descriptor, uses futimes(2) if available,
425otherwise returns ENOSYS, so this is not portable.
426
427Examples:
428
429 # set atime and mtime to current time (basically touch(1)):
430 aio_utime "path", undef, undef;
431 # set atime to current time and mtime to beginning of the epoch:
432 aio_utime "path", time, undef; # undef==0
433
434
435=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
436
437Works like perl's C<chown> function, except that C<undef> for either $uid
438or $gid is being interpreted as "do not change" (but -1 can also be used).
439
440Examples:
441
442 # same as "chown root path" in the shell:
443 aio_chown "path", 0, -1;
444 # same as above:
445 aio_chown "path", 0, undef;
446
447
448=item aio_chmod $fh_or_path, $mode, $callback->($status)
449
450Works like perl's C<chmod> function.
451
452
404=item aio_unlink $pathname, $callback->($status) 453=item aio_unlink $pathname, $callback->($status)
405 454
406Asynchronously unlink (delete) a file and call the callback with the 455Asynchronously unlink (delete) a file and call the callback with the
407result code. 456result code.
408 457
458
459=item aio_mknod $path, $mode, $dev, $callback->($status)
460
461[EXPERIMENTAL]
462
463Asynchronously create a device node (or fifo). See mknod(2).
464
465The only (POSIX-) portable way of calling this function is:
466
467 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
468
469
409=item aio_link $srcpath, $dstpath, $callback->($status) 470=item aio_link $srcpath, $dstpath, $callback->($status)
410 471
411Asynchronously create a new link to the existing object at C<$srcpath> at 472Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 473the path C<$dstpath> and call the callback with the result code.
413 474
475
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 476=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 477
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 478Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
417the path C<$dstpath> and call the callback with the result code. 479the path C<$dstpath> and call the callback with the result code.
418 480
481
482=item aio_readlink $path, $callback->($link)
483
484Asynchronously read the symlink specified by C<$path> and pass it to
485the callback. If an error occurs, nothing or undef gets passed to the
486callback.
487
488
419=item aio_rename $srcpath, $dstpath, $callback->($status) 489=item aio_rename $srcpath, $dstpath, $callback->($status)
420 490
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 491Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 492rename(2) and call the callback with the result code.
423 493
494
495=item aio_mkdir $pathname, $mode, $callback->($status)
496
497Asynchronously mkdir (create) a directory and call the callback with
498the result code. C<$mode> will be modified by the umask at the time the
499request is executed, so do not change your umask.
500
501
424=item aio_rmdir $pathname, $callback->($status) 502=item aio_rmdir $pathname, $callback->($status)
425 503
426Asynchronously rmdir (delete) a directory and call the callback with the 504Asynchronously rmdir (delete) a directory and call the callback with the
427result code. 505result code.
506
428 507
429=item aio_readdir $pathname, $callback->($entries) 508=item aio_readdir $pathname, $callback->($entries)
430 509
431Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 510Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432directory (i.e. opendir + readdir + closedir). The entries will not be 511directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 512sorted, and will B<NOT> include the C<.> and C<..> entries.
434 513
435The callback a single argument which is either C<undef> or an array-ref 514The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 515with the filenames.
516
517
518=item aio_load $path, $data, $callback->($status)
519
520This is a composite request that tries to fully load the given file into
521memory. Status is the same as with aio_read.
522
523=cut
524
525sub aio_load($$;$) {
526 aio_block {
527 my ($path, undef, $cb) = @_;
528 my $data = \$_[1];
529
530 my $pri = aioreq_pri;
531 my $grp = aio_group $cb;
532
533 aioreq_pri $pri;
534 add $grp aio_open $path, O_RDONLY, 0, sub {
535 my $fh = shift
536 or return $grp->result (-1);
537
538 aioreq_pri $pri;
539 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
540 $grp->result ($_[0]);
541 };
542 };
543
544 $grp
545 }
546}
547
548=item aio_copy $srcpath, $dstpath, $callback->($status)
549
550Try to copy the I<file> (directories not supported as either source or
551destination) from C<$srcpath> to C<$dstpath> and call the callback with
552the C<0> (error) or C<-1> ok.
553
554This is a composite request that it creates the destination file with
555mode 0200 and copies the contents of the source file into it using
556C<aio_sendfile>, followed by restoring atime, mtime, access mode and
557uid/gid, in that order.
558
559If an error occurs, the partial destination file will be unlinked, if
560possible, except when setting atime, mtime, access mode and uid/gid, where
561errors are being ignored.
562
563=cut
564
565sub aio_copy($$;$) {
566 aio_block {
567 my ($src, $dst, $cb) = @_;
568
569 my $pri = aioreq_pri;
570 my $grp = aio_group $cb;
571
572 aioreq_pri $pri;
573 add $grp aio_open $src, O_RDONLY, 0, sub {
574 if (my $src_fh = $_[0]) {
575 my @stat = stat $src_fh;
576
577 aioreq_pri $pri;
578 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
579 if (my $dst_fh = $_[0]) {
580 aioreq_pri $pri;
581 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
582 if ($_[0] == $stat[7]) {
583 $grp->result (0);
584 close $src_fh;
585
586 # those should not normally block. should. should.
587 utime $stat[8], $stat[9], $dst;
588 chmod $stat[2] & 07777, $dst_fh;
589 chown $stat[4], $stat[5], $dst_fh;
590 close $dst_fh;
591 } else {
592 $grp->result (-1);
593 close $src_fh;
594 close $dst_fh;
595
596 aioreq $pri;
597 add $grp aio_unlink $dst;
598 }
599 };
600 } else {
601 $grp->result (-1);
602 }
603 },
604
605 } else {
606 $grp->result (-1);
607 }
608 };
609
610 $grp
611 }
612}
613
614=item aio_move $srcpath, $dstpath, $callback->($status)
615
616Try to move the I<file> (directories not supported as either source or
617destination) from C<$srcpath> to C<$dstpath> and call the callback with
618the C<0> (error) or C<-1> ok.
619
620This is a composite request that tries to rename(2) the file first. If
621rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
622that is successful, unlinking the C<$srcpath>.
623
624=cut
625
626sub aio_move($$;$) {
627 aio_block {
628 my ($src, $dst, $cb) = @_;
629
630 my $pri = aioreq_pri;
631 my $grp = aio_group $cb;
632
633 aioreq_pri $pri;
634 add $grp aio_rename $src, $dst, sub {
635 if ($_[0] && $! == EXDEV) {
636 aioreq_pri $pri;
637 add $grp aio_copy $src, $dst, sub {
638 $grp->result ($_[0]);
639
640 if (!$_[0]) {
641 aioreq_pri $pri;
642 add $grp aio_unlink $src;
643 }
644 };
645 } else {
646 $grp->result ($_[0]);
647 }
648 };
649
650 $grp
651 }
652}
437 653
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 654=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 655
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 656Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 657efficiently separate the entries of directory C<$path> into two sets of
… …
487as those tend to return 0 or 1 as link counts, which disables the 703as those tend to return 0 or 1 as link counts, which disables the
488directory counting heuristic. 704directory counting heuristic.
489 705
490=cut 706=cut
491 707
492sub aio_scandir($$$) { 708sub aio_scandir($$;$) {
709 aio_block {
493 my ($path, $maxreq, $cb) = @_; 710 my ($path, $maxreq, $cb) = @_;
494 711
495 my $pri = aioreq_pri; 712 my $pri = aioreq_pri;
496 713
497 my $grp = aio_group $cb; 714 my $grp = aio_group $cb;
498 715
499 $maxreq = 4 if $maxreq <= 0; 716 $maxreq = 4 if $maxreq <= 0;
500 717
501 # stat once 718 # stat once
502 aioreq_pri $pri;
503 add $grp aio_stat $path, sub {
504 return $grp->result () if $_[0];
505 my $now = time;
506 my $hash1 = join ":", (stat _)[0,1,3,7,9];
507
508 # read the directory entries
509 aioreq_pri $pri; 719 aioreq_pri $pri;
510 add $grp aio_readdir $path, sub { 720 add $grp aio_stat $path, sub {
511 my $entries = shift
512 or return $grp->result (); 721 return $grp->result () if $_[0];
722 my $now = time;
723 my $hash1 = join ":", (stat _)[0,1,3,7,9];
513 724
514 # stat the dir another time 725 # read the directory entries
515 aioreq_pri $pri; 726 aioreq_pri $pri;
727 add $grp aio_readdir $path, sub {
728 my $entries = shift
729 or return $grp->result ();
730
731 # stat the dir another time
732 aioreq_pri $pri;
516 add $grp aio_stat $path, sub { 733 add $grp aio_stat $path, sub {
517 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 734 my $hash2 = join ":", (stat _)[0,1,3,7,9];
518 735
519 my $ndirs; 736 my $ndirs;
520 737
521 # take the slow route if anything looks fishy 738 # take the slow route if anything looks fishy
522 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 739 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523 $ndirs = -1; 740 $ndirs = -1;
524 } else { 741 } else {
525 # if nlink == 2, we are finished 742 # if nlink == 2, we are finished
526 # on non-posix-fs's, we rely on nlink < 2 743 # on non-posix-fs's, we rely on nlink < 2
527 $ndirs = (stat _)[3] - 2 744 $ndirs = (stat _)[3] - 2
528 or return $grp->result ([], $entries); 745 or return $grp->result ([], $entries);
529 } 746 }
530 747
531 # sort into likely dirs and likely nondirs 748 # sort into likely dirs and likely nondirs
532 # dirs == files without ".", short entries first 749 # dirs == files without ".", short entries first
533 $entries = [map $_->[0], 750 $entries = [map $_->[0],
534 sort { $b->[1] cmp $a->[1] } 751 sort { $b->[1] cmp $a->[1] }
535 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 752 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536 @$entries]; 753 @$entries];
537 754
538 my (@dirs, @nondirs); 755 my (@dirs, @nondirs);
539 756
540 my $statgrp = add $grp aio_group sub { 757 my $statgrp = add $grp aio_group sub {
541 $grp->result (\@dirs, \@nondirs); 758 $grp->result (\@dirs, \@nondirs);
542 }; 759 };
543 760
544 limit $statgrp $maxreq; 761 limit $statgrp $maxreq;
545 feed $statgrp sub { 762 feed $statgrp sub {
546 return unless @$entries; 763 return unless @$entries;
547 my $entry = pop @$entries; 764 my $entry = pop @$entries;
548 765
549 aioreq_pri $pri; 766 aioreq_pri $pri;
550 add $statgrp aio_stat "$path/$entry/.", sub { 767 add $statgrp aio_stat "$path/$entry/.", sub {
551 if ($_[0] < 0) { 768 if ($_[0] < 0) {
552 push @nondirs, $entry; 769 push @nondirs, $entry;
553 } else { 770 } else {
554 # need to check for real directory 771 # need to check for real directory
555 aioreq_pri $pri; 772 aioreq_pri $pri;
556 add $statgrp aio_lstat "$path/$entry", sub { 773 add $statgrp aio_lstat "$path/$entry", sub {
557 if (-d _) { 774 if (-d _) {
558 push @dirs, $entry; 775 push @dirs, $entry;
559 776
560 unless (--$ndirs) { 777 unless (--$ndirs) {
561 push @nondirs, @$entries; 778 push @nondirs, @$entries;
562 feed $statgrp; 779 feed $statgrp;
780 }
781 } else {
782 push @nondirs, $entry;
563 } 783 }
564 } else {
565 push @nondirs, $entry;
566 } 784 }
567 } 785 }
568 } 786 };
569 }; 787 };
570 }; 788 };
571 }; 789 };
572 }; 790 };
791
792 $grp
573 }; 793 }
794}
574 795
796=item aio_rmtree $path, $callback->($status)
797
798Delete a directory tree starting (and including) C<$path>, return the
799status of the final C<rmdir> only. This is a composite request that
800uses C<aio_scandir> to recurse into and rmdir directories, and unlink
801everything else.
802
803=cut
804
805sub aio_rmtree;
806sub aio_rmtree($;$) {
807 aio_block {
808 my ($path, $cb) = @_;
809
810 my $pri = aioreq_pri;
811 my $grp = aio_group $cb;
812
813 aioreq_pri $pri;
814 add $grp aio_scandir $path, 0, sub {
815 my ($dirs, $nondirs) = @_;
816
817 my $dirgrp = aio_group sub {
818 add $grp aio_rmdir $path, sub {
819 $grp->result ($_[0]);
820 };
821 };
822
823 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
824 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
825
826 add $grp $dirgrp;
827 };
828
575 $grp 829 $grp
830 }
576} 831}
577 832
578=item aio_fsync $fh, $callback->($status) 833=item aio_fsync $fh, $callback->($status)
579 834
580Asynchronously call fsync on the given filehandle and call the callback 835Asynchronously call fsync on the given filehandle and call the callback
… …
794 1049
795=back 1050=back
796 1051
797=head2 SUPPORT FUNCTIONS 1052=head2 SUPPORT FUNCTIONS
798 1053
1054=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1055
799=over 4 1056=over 4
800 1057
801=item $fileno = IO::AIO::poll_fileno 1058=item $fileno = IO::AIO::poll_fileno
802 1059
803Return the I<request result pipe file descriptor>. This filehandle must be 1060Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 1064
808See C<poll_cb> for an example. 1065See C<poll_cb> for an example.
809 1066
810=item IO::AIO::poll_cb 1067=item IO::AIO::poll_cb
811 1068
812Process all outstanding events on the result pipe. You have to call this 1069Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1070regularly. Returns the number of events processed. Returns immediately
814when no events are outstanding. 1071when no events are outstanding. The amount of events processed depends on
1072the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1073
816If not all requests were processed for whatever reason, the filehandle 1074If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1075will still be ready when C<poll_cb> returns.
818 1076
819Example: Install an Event watcher that automatically calls 1077Example: Install an Event watcher that automatically calls
… …
821 1079
822 Event->io (fd => IO::AIO::poll_fileno, 1080 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1081 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1082 cb => \&IO::AIO::poll_cb);
825 1083
826=item IO::AIO::poll_some $max_requests 1084=item IO::AIO::max_poll_reqs $nreqs
827 1085
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1086=item IO::AIO::max_poll_time $seconds
829at a time.
830 1087
831Useful if you want to ensure some level of interactiveness when perl is 1088These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1089that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1090the maximum amount of time (default C<0>, meaning infinity) spent in
1091C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1092of time C<poll_cb> is allowed to use).
1093
1094Setting C<max_poll_time> to a non-zero value creates an overhead of one
1095syscall per request processed, which is not normally a problem unless your
1096callbacks are really really fast or your OS is really really slow (I am
1097not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1098
1099Setting these is useful if you want to ensure some level of
1100interactiveness when perl is not fast enough to process all requests in
1101time.
1102
1103For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1104
834Example: Install an Event watcher that automatically calls 1105Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1106IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1107program get the CPU sometimes even under high AIO load.
837 1108
1109 # try not to spend much more than 0.1s in poll_cb
1110 IO::AIO::max_poll_time 0.1;
1111
1112 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1113 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1114 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1115 cb => &IO::AIO::poll_cb);
841 1116
842=item IO::AIO::poll_wait 1117=item IO::AIO::poll_wait
843 1118
1119If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1120phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1121does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1122synchronously wait for some requests to finish).
847 1123
848See C<nreqs> for an example. 1124See C<nreqs> for an example.
849 1125
1126=item IO::AIO::poll
1127
1128Waits until some requests have been handled.
1129
1130Returns the number of requests processed, but is otherwise strictly
1131equivalent to:
1132
1133 IO::AIO::poll_wait, IO::AIO::poll_cb
1134
850=item IO::AIO::nreqs 1135=item IO::AIO::flush
851 1136
852Returns the number of requests currently in the ready, execute or pending 1137Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1138
855Example: wait till there are no outstanding requests anymore: 1139Strictly equivalent to:
856 1140
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1141 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1142 while IO::AIO::nreqs;
859 1143
860=item IO::AIO::nready 1144=back
861 1145
862Returns the number of requests currently in the ready state (not yet 1146=head3 CONTROLLING THE NUMBER OF THREADS
863executed).
864 1147
865=item IO::AIO::npending 1148=over
866
867Returns the number of requests currently in the pending state (executed,
868but not yet processed by poll_cb).
869
870=item IO::AIO::flush
871
872Wait till all outstanding AIO requests have been handled.
873
874Strictly equivalent to:
875
876 IO::AIO::poll_wait, IO::AIO::poll_cb
877 while IO::AIO::nreqs;
878
879=item IO::AIO::poll
880
881Waits until some requests have been handled.
882
883Strictly equivalent to:
884
885 IO::AIO::poll_wait, IO::AIO::poll_cb
886 if IO::AIO::nreqs;
887 1149
888=item IO::AIO::min_parallel $nthreads 1150=item IO::AIO::min_parallel $nthreads
889 1151
890Set the minimum number of AIO threads to C<$nthreads>. The current 1152Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1153default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1154concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1155however, is unlimited).
894 1156
895IO::AIO starts threads only on demand, when an AIO request is queued and 1157IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1158no free thread exists. Please note that queueing up a hundred requests can
1159create demand for a hundred threads, even if it turns out that everything
1160is in the cache and could have been processed faster by a single thread.
897 1161
898It is recommended to keep the number of threads relatively low, as some 1162It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1163Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1164(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1165versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1179This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1180that all threads are killed and that there are no outstanding requests.
917 1181
918Under normal circumstances you don't need to call this function. 1182Under normal circumstances you don't need to call this function.
919 1183
1184=item IO::AIO::max_idle $nthreads
1185
1186Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1187threads that did not get a request to process within 10 seconds). That
1188means if a thread becomes idle while C<$nthreads> other threads are also
1189idle, it will free its resources and exit.
1190
1191This is useful when you allow a large number of threads (e.g. 100 or 1000)
1192to allow for extremely high load situations, but want to free resources
1193under normal circumstances (1000 threads can easily consume 30MB of RAM).
1194
1195The default is probably ok in most situations, especially if thread
1196creation is fast. If thread creation is very slow on your system you might
1197want to use larger values.
1198
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1199=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
921 1200
922This is a very bad function to use in interactive programs because it 1201This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1202blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1203use an C<aio_group> together with a feed callback.
… …
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1214C<max_oustsanding> is mainly useful in simple scripts (with low values) or
936as a stop gap to shield against fatal memory overflow (with large values). 1215as a stop gap to shield against fatal memory overflow (with large values).
937 1216
938=back 1217=back
939 1218
1219=head3 STATISTICAL INFORMATION
1220
1221=over
1222
1223=item IO::AIO::nreqs
1224
1225Returns the number of requests currently in the ready, execute or pending
1226states (i.e. for which their callback has not been invoked yet).
1227
1228Example: wait till there are no outstanding requests anymore:
1229
1230 IO::AIO::poll_wait, IO::AIO::poll_cb
1231 while IO::AIO::nreqs;
1232
1233=item IO::AIO::nready
1234
1235Returns the number of requests currently in the ready state (not yet
1236executed).
1237
1238=item IO::AIO::npending
1239
1240Returns the number of requests currently in the pending state (executed,
1241but not yet processed by poll_cb).
1242
1243=back
1244
940=cut 1245=cut
941 1246
942# support function to convert a fd into a perl filehandle 1247# support function to convert a fd into a perl filehandle
943sub _fd2fh { 1248sub _fd2fh {
944 return undef if $_[0] < 0; 1249 return undef if $_[0] < 0;
… …
954 1259
955 *$sym 1260 *$sym
956} 1261}
957 1262
958min_parallel 8; 1263min_parallel 8;
1264
1265END { flush }
959 1266
9601; 12671;
961 1268
962=head2 FORK BEHAVIOUR 1269=head2 FORK BEHAVIOUR
963 1270

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