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Revision 1.96 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.108 by root, Fri Jun 1 13:25:50 2007 UTC

62etc.), 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
63normally 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
64on 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
65concurrently. 65concurrently.
66 66
67While most of this works on all types of file descriptors (for example 67While most of this works on all types of file descriptors (for
68sockets), using these functions on file descriptors that support 68example sockets), using these functions on file descriptors that
69nonblocking operation (again, sockets, pipes etc.) is very inefficient or 69support nonblocking operation (again, sockets, pipes etc.) is very
70might not work (aio_read fails on sockets/pipes/fifos). Use an event loop 70inefficient. Use an event loop for that (such as the L<Event|Event>
71for that (such as the L<Event|Event> module): IO::AIO will naturally fit 71module): IO::AIO will naturally fit into such an event loop itself.
72into such an event loop itself.
73 72
74In this version, a number of threads are started that execute your 73In this version, a number of threads are started that execute your
75requests and signal their completion. You don't need thread support 74requests and signal their completion. You don't need thread support
76in 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
77to 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
79not 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
80files currently, for example), and they would only support aio_read and 79files currently, for example), and they would only support aio_read and
81aio_write, so the remaining functionality would have to be implemented 80aio_write, so the remaining functionality would have to be implemented
82using threads anyway. 81using threads anyway.
83 82
84Although the module will work with in the presence of other (Perl-) 83Although the module will work in the presence of other (Perl-) threads,
85threads, it is currently not reentrant in any way, so use appropriate 84it is currently not reentrant in any way, so use appropriate locking
86locking 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
87never call C<poll_cb> (or other C<aio_> functions) recursively. 86call C<poll_cb> (or other C<aio_> functions) recursively.
88 87
89=head2 EXAMPLE 88=head2 EXAMPLE
90 89
91This is a simple example that uses the Event module and loads 90This is a simple example that uses the Event module and loads
92F</etc/passwd> asynchronously: 91F</etc/passwd> asynchronously:
190use strict 'vars'; 189use strict 'vars';
191 190
192use base 'Exporter'; 191use base 'Exporter';
193 192
194BEGIN { 193BEGIN {
195 our $VERSION = '2.21'; 194 our $VERSION = '2.4';
196 195
197 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
198 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
199 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link 198 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
200 aio_move 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);
201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); 201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203 min_parallel max_parallel max_idle 203 min_parallel max_parallel max_idle
204 nreqs nready npending nthreads 204 nreqs nready npending nthreads
205 max_poll_time max_poll_reqs); 205 max_poll_time max_poll_reqs);
271 aio_read $_[0], ..., sub { 271 aio_read $_[0], ..., sub {
272 ... 272 ...
273 }; 273 };
274 }; 274 };
275 275
276
276=item aioreq_nice $pri_adjust 277=item aioreq_nice $pri_adjust
277 278
278Similar 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
279priority, so the effect is cumulative. 280priority, so the effect is cumulative.
281
280 282
281=item aio_open $pathname, $flags, $mode, $callback->($fh) 283=item aio_open $pathname, $flags, $mode, $callback->($fh)
282 284
283Asynchronously 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
284created filehandle for the file. 286created filehandle for the file.
290list. They are the same as used by C<sysopen>. 292list. They are the same as used by C<sysopen>.
291 293
292Likewise, 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
293didn'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>,
294except 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,
295and C<0666> or C<0777> if you do). 297and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
298by the umask in effect then the request is being executed, so better never
299change the umask.
296 300
297Example: 301Example:
298 302
299 aio_open "/etc/passwd", O_RDONLY, 0, sub { 303 aio_open "/etc/passwd", O_RDONLY, 0, sub {
300 if ($_[0]) { 304 if ($_[0]) {
303 } else { 307 } else {
304 die "open failed: $!\n"; 308 die "open failed: $!\n";
305 } 309 }
306 }; 310 };
307 311
312
308=item aio_close $fh, $callback->($status) 313=item aio_close $fh, $callback->($status)
309 314
310Asynchronously close a file and call the callback with the result 315Asynchronously close a file and call the callback with the result
311code. I<WARNING:> although accepted, you should not pass in a perl 316code. I<WARNING:> although accepted, you should not pass in a perl
312filehandle here, as perl will likely close the file descriptor another 317filehandle here, as perl will likely close the file descriptor another
314C<close> or just let filehandles go out of scope. 319C<close> or just let filehandles go out of scope.
315 320
316This 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
317therefore best to avoid this function. 322therefore best to avoid this function.
318 323
324
319=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 325=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320 326
321=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 327=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322 328
323Reads 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>
324into 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
325callback 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
326like 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.
327 335
328The 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
329is outstanding. Modifying it can result in segfaults or WW3 (if the 337is outstanding. Modifying it can result in segfaults or World War III (if
330necessary/optional hardware is installed). 338the necessary/optional hardware is installed).
331 339
332Example: 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
333offset C<0> within the scalar: 341offset C<0> within the scalar:
334 342
335 aio_read $fh, 7, 15, $buffer, 0, sub { 343 aio_read $fh, 7, 15, $buffer, 0, sub {
336 $_[0] > 0 or die "read error: $!"; 344 $_[0] > 0 or die "read error: $!";
337 print "read $_[0] bytes: <$buffer>\n"; 345 print "read $_[0] bytes: <$buffer>\n";
338 }; 346 };
347
339 348
340=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)
341 350
342Tries 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
343reading 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
357C<$in_fh> than are written, and there is no way to find out how many 366C<$in_fh> than are written, and there is no way to find out how many
358bytes 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
359provides 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
360value 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
361read. 370read.
371
362 372
363=item aio_readahead $fh,$offset,$length, $callback->($retval) 373=item aio_readahead $fh,$offset,$length, $callback->($retval)
364 374
365C<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
366subsequent 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>
372file. The current file offset of the file is left unchanged. 382file. The current file offset of the file is left unchanged.
373 383
374If 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
375emulated by simply reading the data, which would have a similar effect. 385emulated by simply reading the data, which would have a similar effect.
376 386
387
377=item aio_stat $fh_or_path, $callback->($status) 388=item aio_stat $fh_or_path, $callback->($status)
378 389
379=item aio_lstat $fh, $callback->($status) 390=item aio_lstat $fh, $callback->($status)
380 391
381Works 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
394 aio_stat "/etc/passwd", sub { 405 aio_stat "/etc/passwd", sub {
395 $_[0] and die "stat failed: $!"; 406 $_[0] and die "stat failed: $!";
396 print "size is ", -s _, "\n"; 407 print "size is ", -s _, "\n";
397 }; 408 };
398 409
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
399=item aio_unlink $pathname, $callback->($status) 447=item aio_unlink $pathname, $callback->($status)
400 448
401Asynchronously unlink (delete) a file and call the callback with the 449Asynchronously unlink (delete) a file and call the callback with the
402result code. 450result code.
403 451
452
404=item aio_mknod $path, $mode, $dev, $callback->($status) 453=item aio_mknod $path, $mode, $dev, $callback->($status)
405 454
406[EXPERIMENTAL] 455[EXPERIMENTAL]
407 456
408Asynchronously create a device node (or fifo). See mknod(2). 457Asynchronously create a device node (or fifo). See mknod(2).
409 458
410The only (POSIX-) portable way of calling this function is: 459The only (POSIX-) portable way of calling this function is:
411 460
412 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 461 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
462
413 463
414=item aio_link $srcpath, $dstpath, $callback->($status) 464=item aio_link $srcpath, $dstpath, $callback->($status)
415 465
416Asynchronously 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
417the path C<$dstpath> and call the callback with the result code. 467the path C<$dstpath> and call the callback with the result code.
418 468
469
419=item aio_symlink $srcpath, $dstpath, $callback->($status) 470=item aio_symlink $srcpath, $dstpath, $callback->($status)
420 471
421Asynchronously 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
422the path C<$dstpath> and call the callback with the result code. 473the path C<$dstpath> and call the callback with the result code.
474
423 475
424=item aio_readlink $path, $callback->($link) 476=item aio_readlink $path, $callback->($link)
425 477
426Asynchronously read the symlink specified by C<$path> and pass it to 478Asynchronously read the symlink specified by C<$path> and pass it to
427the callback. If an error occurs, nothing or undef gets passed to the 479the callback. If an error occurs, nothing or undef gets passed to the
428callback. 480callback.
429 481
482
430=item aio_rename $srcpath, $dstpath, $callback->($status) 483=item aio_rename $srcpath, $dstpath, $callback->($status)
431 484
432Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 485Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
433rename(2) and call the callback with the result code. 486rename(2) and call the callback with the result code.
434 487
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
435=item aio_rmdir $pathname, $callback->($status) 496=item aio_rmdir $pathname, $callback->($status)
436 497
437Asynchronously rmdir (delete) a directory and call the callback with the 498Asynchronously rmdir (delete) a directory and call the callback with the
438result code. 499result code.
500
439 501
440=item aio_readdir $pathname, $callback->($entries) 502=item aio_readdir $pathname, $callback->($entries)
441 503
442Unlike 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
443directory (i.e. opendir + readdir + closedir). The entries will not be 505directory (i.e. opendir + readdir + closedir). The entries will not be
444sorted, and will B<NOT> include the C<.> and C<..> entries. 506sorted, and will B<NOT> include the C<.> and C<..> entries.
445 507
446The 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
447with 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}
448 541
449=item aio_copy $srcpath, $dstpath, $callback->($status) 542=item aio_copy $srcpath, $dstpath, $callback->($status)
450 543
451Try 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
452destination) from C<$srcpath> to C<$dstpath> and call the callback with 545destination) from C<$srcpath> to C<$dstpath> and call the callback with
604as 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
605directory counting heuristic. 698directory counting heuristic.
606 699
607=cut 700=cut
608 701
609sub aio_scandir($$$) { 702sub aio_scandir($$;$) {
610 aio_block { 703 aio_block {
611 my ($path, $maxreq, $cb) = @_; 704 my ($path, $maxreq, $cb) = @_;
612 705
613 my $pri = aioreq_pri; 706 my $pri = aioreq_pri;
614 707
692 785
693 $grp 786 $grp
694 } 787 }
695} 788}
696 789
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
823 $grp
824 }
825}
826
697=item aio_fsync $fh, $callback->($status) 827=item aio_fsync $fh, $callback->($status)
698 828
699Asynchronously call fsync on the given filehandle and call the callback 829Asynchronously call fsync on the given filehandle and call the callback
700with the fsync result code. 830with the fsync result code.
701 831
1003Strictly equivalent to: 1133Strictly equivalent to:
1004 1134
1005 IO::AIO::poll_wait, IO::AIO::poll_cb 1135 IO::AIO::poll_wait, IO::AIO::poll_cb
1006 while IO::AIO::nreqs; 1136 while IO::AIO::nreqs;
1007 1137
1138=back
1139
1008=head3 CONTROLLING THE NUMBER OF THREADS 1140=head3 CONTROLLING THE NUMBER OF THREADS
1141
1142=over
1009 1143
1010=item IO::AIO::min_parallel $nthreads 1144=item IO::AIO::min_parallel $nthreads
1011 1145
1012Set the minimum number of AIO threads to C<$nthreads>. The current 1146Set the minimum number of AIO threads to C<$nthreads>. The current
1013default is C<8>, which means eight asynchronous operations can execute 1147default is C<8>, which means eight asynchronous operations can execute
1072 1206
1073You can still queue as many requests as you want. Therefore, 1207You can still queue as many requests as you want. Therefore,
1074C<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
1075as 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).
1076 1210
1211=back
1212
1077=head3 STATISTICAL INFORMATION 1213=head3 STATISTICAL INFORMATION
1214
1215=over
1078 1216
1079=item IO::AIO::nreqs 1217=item IO::AIO::nreqs
1080 1218
1081Returns the number of requests currently in the ready, execute or pending 1219Returns the number of requests currently in the ready, execute or pending
1082states (i.e. for which their callback has not been invoked yet). 1220states (i.e. for which their callback has not been invoked yet).

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