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Revision 1.174 by root, Sun Jan 10 20:28:43 2010 UTC vs.
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC

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4 4
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", IO::AIO::O_RDONLY, 0, sub {
10 my $fh = shift 10 my $fh = shift
11 or die "/etc/passwd: $!"; 11 or die "/etc/passwd: $!";
12 ... 12 ...
13 }; 13 };
14 14
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25 my $req = aio_unlink "/tmp/file", sub { }; 25 my $req = aio_unlink "/tmp/file", sub { };
26 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
27 27
28 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
29 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r',
40 cb => \&IO::AIO::poll_cb);
41
42 # Glib/Gtk2 integration
43 add_watch Glib::IO IO::AIO::poll_fileno,
44 in => sub { IO::AIO::poll_cb; 1 };
45
46 # Tk integration
47 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48 readable => \&IO::AIO::poll_cb);
49
50 # Danga::Socket integration
51 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52 \&IO::AIO::poll_cb);
53 30
54=head1 DESCRIPTION 31=head1 DESCRIPTION
55 32
56This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
57operating system supports. It is implemented as an interface to C<libeio> 34operating system supports. It is implemented as an interface to C<libeio>
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99 76
100 # register the IO::AIO callback with EV 77 # register the IO::AIO callback with EV
101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 79
103 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105 my $fh = shift 82 my $fh = shift
106 or die "error while opening: $!"; 83 or die "error while opening: $!";
107 84
108 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh; 86 my $size = -s $fh;
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191use common::sense; 168use common::sense;
192 169
193use base 'Exporter'; 170use base 'Exporter';
194 171
195BEGIN { 172BEGIN {
196 our $VERSION = '3.5'; 173 our $VERSION = '4.0';
197 174
198 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
199 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
200 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
201 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
179 aio_pathsync aio_readahead
202 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
203 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
204 aio_chmod aio_utime aio_truncate 182 aio_chmod aio_utime aio_truncate
205 aio_msync aio_mtouch aio_statvfs); 183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs
185 aio_wd);
206 186
207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
210 nreqs nready npending nthreads 190 nreqs nready npending nthreads
211 max_poll_time max_poll_reqs 191 max_poll_time max_poll_reqs
212 sendfile fadvise); 192 sendfile fadvise madvise
193 mmap munmap munlock munlockall);
213 194
214 push @AIO_REQ, qw(aio_busy); # not exported 195 push @AIO_REQ, qw(aio_busy); # not exported
215 196
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 198
218 require XSLoader; 199 require XSLoader;
219 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
220} 201}
221 202
222=head1 FUNCTIONS 203=head1 FUNCTIONS
204
205=head2 QUICK OVERVIEW
206
207This section simply lists the prototypes of the most important functions
208for quick reference. See the following sections for function-by-function
209documentation.
210
211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $pathname, $callback->($link)
230 aio_realpath $pathname, $callback->($link)
231 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
238 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $pathname, $callback->($status)
243 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...)
254 aio_nop $callback->()
255
256 $prev_pri = aioreq_pri [$pri]
257 aioreq_nice $pri_adjust
258
259 IO::AIO::poll_wait
260 IO::AIO::poll_cb
261 IO::AIO::poll
262 IO::AIO::flush
263 IO::AIO::max_poll_reqs $nreqs
264 IO::AIO::max_poll_time $seconds
265 IO::AIO::min_parallel $nthreads
266 IO::AIO::max_parallel $nthreads
267 IO::AIO::max_idle $nthreads
268 IO::AIO::idle_timeout $seconds
269 IO::AIO::max_outstanding $maxreqs
270 IO::AIO::nreqs
271 IO::AIO::nready
272 IO::AIO::npending
273
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice
276 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall
223 280
224=head2 AIO REQUEST FUNCTIONS 281=head2 AIO REQUEST FUNCTIONS
225 282
226All the C<aio_*> calls are more or less thin wrappers around the syscall 283All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 284with the same name (sans C<aio_>). The arguments are similar or identical,
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235internally until the request has finished. 292internally until the request has finished.
236 293
237All functions return request objects of type L<IO::AIO::REQ> that allow 294All functions return request objects of type L<IO::AIO::REQ> that allow
238further manipulation of those requests while they are in-flight. 295further manipulation of those requests while they are in-flight.
239 296
240The pathnames you pass to these routines I<must> be absolute and 297The pathnames you pass to these routines I<should> be absolute. The
241encoded as octets. The reason for the former is that at the time the 298reason for this is that at the time the request is being executed, the
242request is being executed, the current working directory could have 299current working directory could have changed. Alternatively, you can make
243changed. Alternatively, you can make sure that you never change the 300sure that you never change the current working directory anywhere in
244current working directory anywhere in the program and then use relative 301the program and then use relative paths. Lastly, you can take advantage
245paths. 302of IO::AIOs working directory abstraction - see the description of the
303C<IO::AIO::WD> class later in this document.
246 304
247To encode pathnames as octets, either make sure you either: a) always pass 305To encode pathnames as octets, either make sure you either: a) always pass
248in filenames you got from outside (command line, readdir etc.) without 306in filenames you got from outside (command line, readdir etc.) without
249tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 307tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
250your pathnames to the locale (or other) encoding in effect in the user 308your pathnames to the locale (or other) encoding in effect in the user
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307by the umask in effect then the request is being executed, so better never 365by the umask in effect then the request is being executed, so better never
308change the umask. 366change the umask.
309 367
310Example: 368Example:
311 369
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 370 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 371 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 372 print "open successful, fh is $_[0]\n";
315 ... 373 ...
316 } else { 374 } else {
317 die "open failed: $!\n"; 375 die "open failed: $!\n";
318 } 376 }
319 }; 377 };
320 378
379In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
380C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
381following POSIX and non-POSIX constants are available (missing ones on
382your system are, as usual, C<0>):
383
384C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
385C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
386C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
387
321 388
322=item aio_close $fh, $callback->($status) 389=item aio_close $fh, $callback->($status)
323 390
324Asynchronously close a file and call the callback with the result 391Asynchronously close a file and call the callback with the result
325code. 392code.
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375 442
376Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 443Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377reading at byte offset C<$in_offset>, and starts writing at the current 444reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 445file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 446than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 447other. The same C<$in_fh> works fine though, as this function does not
448move or use the file offset of C<$in_fh>.
381 449
450Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
451are written, and there is no way to find out how many more bytes have been
452read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
453number of bytes written to C<$out_fh>. Only if the result value equals
454C<$length> one can assume that C<$length> bytes have been read.
455
456Unlike with other C<aio_> functions, it makes a lot of sense to use
457C<aio_sendfile> on non-blocking sockets, as long as one end (typically
458the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
459the socket I/O will be non-blocking. Note, however, that you can run
460into a trap where C<aio_sendfile> reads some data with readahead, then
461fails to write all data, and when the socket is ready the next time, the
462data in the cache is already lost, forcing C<aio_sendfile> to again hit
463the disk. Explicit C<aio_read> + C<aio_write> let's you better control
464resource usage.
465
382This call tries to make use of a native C<sendfile> syscall to provide 466This call tries to make use of a native C<sendfile>-like syscall to
383zero-copy operation. For this to work, C<$out_fh> should refer to a 467provide zero-copy operation. For this to work, C<$out_fh> should refer to
384socket, and C<$in_fh> should refer to mmap'able file. 468a socket, and C<$in_fh> should refer to an mmap'able file.
385 469
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 470If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 471C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388it will be emulated, so you can call C<aio_sendfile> on any type of 472C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389filehandle regardless of the limitations of the operating system. 473type of filehandle regardless of the limitations of the operating system.
390 474
391Please note, however, that C<aio_sendfile> can read more bytes from 475As native sendfile syscalls (as practically any non-POSIX interface hacked
392C<$in_fh> than are written, and there is no way to find out how many 476together in a hurry to improve benchmark numbers) tend to be rather buggy
393bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 477on many systems, this implementation tries to work around some known bugs
394provides the number of bytes written to C<$out_fh>. Only if the result 478in Linux and FreeBSD kernels (probably others, too), but that might fail,
395value equals C<$length> one can assume that C<$length> bytes have been 479so you really really should check the return value of C<aio_sendfile> -
396read. 480fewre bytes than expected might have been transferred.
397 481
398 482
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 483=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 484
401C<aio_readahead> populates the page cache with data from a file so that 485C<aio_readahead> populates the page cache with data from a file so that
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424 508
425Currently, the stats are always 64-bit-stats, i.e. instead of returning an 509Currently, the stats are always 64-bit-stats, i.e. instead of returning an
426error when stat'ing a large file, the results will be silently truncated 510error when stat'ing a large file, the results will be silently truncated
427unless perl itself is compiled with large file support. 511unless perl itself is compiled with large file support.
428 512
513To help interpret the mode and dev/rdev stat values, IO::AIO offers the
514following constants and functions (if not implemented, the constants will
515be C<0> and the functions will either C<croak> or fall back on traditional
516behaviour).
517
518C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
519C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
520C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
521
429Example: Print the length of F</etc/passwd>: 522Example: Print the length of F</etc/passwd>:
430 523
431 aio_stat "/etc/passwd", sub { 524 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 525 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 526 print "size is ", -s _, "\n";
434 }; 527 };
435 528
436 529
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 530=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 531
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 532Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 533whether a file handle or path was passed.
441 534
442On success, the callback is passed a hash reference with the following 535On success, the callback is passed a hash reference with the following
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524 617
525Asynchronously unlink (delete) a file and call the callback with the 618Asynchronously unlink (delete) a file and call the callback with the
526result code. 619result code.
527 620
528 621
529=item aio_mknod $path, $mode, $dev, $callback->($status) 622=item aio_mknod $pathname, $mode, $dev, $callback->($status)
530 623
531[EXPERIMENTAL] 624[EXPERIMENTAL]
532 625
533Asynchronously create a device node (or fifo). See mknod(2). 626Asynchronously create a device node (or fifo). See mknod(2).
534 627
535The only (POSIX-) portable way of calling this function is: 628The only (POSIX-) portable way of calling this function is:
536 629
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 630 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 631
632See C<aio_stat> for info about some potentially helpful extra constants
633and functions.
539 634
540=item aio_link $srcpath, $dstpath, $callback->($status) 635=item aio_link $srcpath, $dstpath, $callback->($status)
541 636
542Asynchronously create a new link to the existing object at C<$srcpath> at 637Asynchronously create a new link to the existing object at C<$srcpath> at
543the path C<$dstpath> and call the callback with the result code. 638the path C<$dstpath> and call the callback with the result code.
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547 642
548Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 643Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
549the path C<$dstpath> and call the callback with the result code. 644the path C<$dstpath> and call the callback with the result code.
550 645
551 646
552=item aio_readlink $path, $callback->($link) 647=item aio_readlink $pathname, $callback->($link)
553 648
554Asynchronously read the symlink specified by C<$path> and pass it to 649Asynchronously read the symlink specified by C<$path> and pass it to
555the callback. If an error occurs, nothing or undef gets passed to the 650the callback. If an error occurs, nothing or undef gets passed to the
556callback. 651callback.
557 652
558 653
654=item aio_realpath $pathname, $callback->($path)
655
656Asynchronously make the path absolute and resolve any symlinks in
657C<$path>. The resulting path only consists of directories (Same as
658L<Cwd::realpath>).
659
660This request can be used to get the absolute path of the current working
661directory by passing it a path of F<.> (a single dot).
662
663
559=item aio_rename $srcpath, $dstpath, $callback->($status) 664=item aio_rename $srcpath, $dstpath, $callback->($status)
560 665
561Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 666Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
562rename(2) and call the callback with the result code. 667rename(2) and call the callback with the result code.
563 668
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585array-ref with the filenames. 690array-ref with the filenames.
586 691
587 692
588=item aio_readdirx $pathname, $flags, $callback->($entries, $flags) 693=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
589 694
590Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune 695Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
591behaviour and output format. In case of an error, C<$entries> will be 696tune behaviour and output format. In case of an error, C<$entries> will be
592C<undef>. 697C<undef>.
593 698
594The flags are a combination of the following constants, ORed together (the 699The flags are a combination of the following constants, ORed together (the
595flags will also be passed to the callback, possibly modified): 700flags will also be passed to the callback, possibly modified):
596 701
597=over 4 702=over 4
598 703
599=item IO::AIO::READDIR_DENTS 704=item IO::AIO::READDIR_DENTS
600 705
601When this flag is off, then the callback gets an arrayref with of names 706When this flag is off, then the callback gets an arrayref consisting of
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 707names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 708C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 709entry in more detail.
605 710
606C<$name> is the name of the entry. 711C<$name> is the name of the entry.
607 712
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620systems that do not deliver the inode information. 725systems that do not deliver the inode information.
621 726
622=item IO::AIO::READDIR_DIRS_FIRST 727=item IO::AIO::READDIR_DIRS_FIRST
623 728
624When this flag is set, then the names will be returned in an order where 729When this flag is set, then the names will be returned in an order where
625likely directories come first. This is useful when you need to quickly 730likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 731you need to quickly find directories, or you want to find all directories
627stat() each entry. 732while avoiding to stat() each entry.
628 733
629If the system returns type information in readdir, then this is used 734If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 735to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 736beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 737short names are tried first.
633 738
634=item IO::AIO::READDIR_STAT_ORDER 739=item IO::AIO::READDIR_STAT_ORDER
635 740
636When this flag is set, then the names will be returned in an order 741When this flag is set, then the names will be returned in an order
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643 748
644=item IO::AIO::READDIR_FOUND_UNKNOWN 749=item IO::AIO::READDIR_FOUND_UNKNOWN
645 750
646This flag should not be set when calling C<aio_readdirx>. Instead, it 751This flag should not be set when calling C<aio_readdirx>. Instead, it
647is being set by C<aio_readdirx>, when any of the C<$type>'s found were 752is being set by C<aio_readdirx>, when any of the C<$type>'s found were
648C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 753C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
649C<$type>'s are known, which can be used to speed up some algorithms. 754C<$type>'s are known, which can be used to speed up some algorithms.
650 755
651=back 756=back
652 757
653 758
654=item aio_load $path, $data, $callback->($status) 759=item aio_load $pathname, $data, $callback->($status)
655 760
656This is a composite request that tries to fully load the given file into 761This is a composite request that tries to fully load the given file into
657memory. Status is the same as with aio_read. 762memory. Status is the same as with aio_read.
658 763
659=cut 764=cut
… …
781 if ($_[0] && $! == EXDEV) { 886 if ($_[0] && $! == EXDEV) {
782 aioreq_pri $pri; 887 aioreq_pri $pri;
783 add $grp aio_copy $src, $dst, sub { 888 add $grp aio_copy $src, $dst, sub {
784 $grp->result ($_[0]); 889 $grp->result ($_[0]);
785 890
786 if (!$_[0]) { 891 unless ($_[0]) {
787 aioreq_pri $pri; 892 aioreq_pri $pri;
788 add $grp aio_unlink $src; 893 add $grp aio_unlink $src;
789 } 894 }
790 }; 895 };
791 } else { 896 } else {
… …
794 }; 899 };
795 900
796 $grp 901 $grp
797} 902}
798 903
799=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 904=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
800 905
801Scans a directory (similar to C<aio_readdir>) but additionally tries to 906Scans a directory (similar to C<aio_readdir>) but additionally tries to
802efficiently separate the entries of directory C<$path> into two sets of 907efficiently separate the entries of directory C<$path> into two sets of
803names, directories you can recurse into (directories), and ones you cannot 908names, directories you can recurse into (directories), and ones you cannot
804recurse into (everything else, including symlinks to directories). 909recurse into (everything else, including symlinks to directories).
… …
835Then entries will be sorted into likely directories a non-initial dot 940Then entries will be sorted into likely directories a non-initial dot
836currently) and likely non-directories (see C<aio_readdirx>). Then every 941currently) and likely non-directories (see C<aio_readdirx>). Then every
837entry plus an appended C</.> will be C<stat>'ed, likely directories first, 942entry plus an appended C</.> will be C<stat>'ed, likely directories first,
838in order of their inode numbers. If that succeeds, it assumes that the 943in order of their inode numbers. If that succeeds, it assumes that the
839entry is a directory or a symlink to directory (which will be checked 944entry is a directory or a symlink to directory (which will be checked
840seperately). This is often faster than stat'ing the entry itself because 945separately). This is often faster than stat'ing the entry itself because
841filesystems might detect the type of the entry without reading the inode 946filesystems might detect the type of the entry without reading the inode
842data (e.g. ext2fs filetype feature), even on systems that cannot return 947data (e.g. ext2fs filetype feature), even on systems that cannot return
843the filetype information on readdir. 948the filetype information on readdir.
844 949
845If the known number of directories (link count - 2) has been reached, the 950If the known number of directories (link count - 2) has been reached, the
… …
861 966
862 my $grp = aio_group $cb; 967 my $grp = aio_group $cb;
863 968
864 $maxreq = 4 if $maxreq <= 0; 969 $maxreq = 4 if $maxreq <= 0;
865 970
866 # stat once 971 # get a wd object
972
867 aioreq_pri $pri; 973 aioreq_pri $pri;
868 add $grp aio_stat $path, sub { 974 add $grp aio_wd $path, sub {
869 return $grp->result () if $_[0]; 975 my $wd = [shift, "."];
870 my $now = time;
871 my $hash1 = join ":", (stat _)[0,1,3,7,9];
872 976
873 # read the directory entries 977 # stat once
874 aioreq_pri $pri; 978 aioreq_pri $pri;
875 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 979 add $grp aio_stat $wd, sub {
876 my $entries = shift
877 or return $grp->result (); 980 return $grp->result () if $_[0];
981 my $now = time;
982 my $hash1 = join ":", (stat _)[0,1,3,7,9];
878 983
879 # stat the dir another time 984 # read the directory entries
880 aioreq_pri $pri; 985 aioreq_pri $pri;
986 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
987 my $entries = shift
988 or return $grp->result ();
989
990 # stat the dir another time
991 aioreq_pri $pri;
881 add $grp aio_stat $path, sub { 992 add $grp aio_stat $wd, sub {
882 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 993 my $hash2 = join ":", (stat _)[0,1,3,7,9];
883 994
884 my $ndirs; 995 my $ndirs;
885 996
886 # take the slow route if anything looks fishy 997 # take the slow route if anything looks fishy
887 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 998 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
888 $ndirs = -1; 999 $ndirs = -1;
889 } else { 1000 } else {
890 # if nlink == 2, we are finished 1001 # if nlink == 2, we are finished
891 # for non-posix-fs's, we rely on nlink < 2 1002 # for non-posix-fs's, we rely on nlink < 2
892 $ndirs = (stat _)[3] - 2 1003 $ndirs = (stat _)[3] - 2
893 or return $grp->result ([], $entries); 1004 or return $grp->result ([], $entries);
894 } 1005 }
895 1006
896 my (@dirs, @nondirs); 1007 my (@dirs, @nondirs);
897 1008
898 my $statgrp = add $grp aio_group sub { 1009 my $statgrp = add $grp aio_group sub {
899 $grp->result (\@dirs, \@nondirs); 1010 $grp->result (\@dirs, \@nondirs);
900 }; 1011 };
901 1012
902 limit $statgrp $maxreq; 1013 limit $statgrp $maxreq;
903 feed $statgrp sub { 1014 feed $statgrp sub {
904 return unless @$entries; 1015 return unless @$entries;
905 my $entry = shift @$entries; 1016 my $entry = shift @$entries;
906 1017
907 aioreq_pri $pri; 1018 aioreq_pri $pri;
1019 $wd->[1] = "$entry/.";
908 add $statgrp aio_stat "$path/$entry/.", sub { 1020 add $statgrp aio_stat $wd, sub {
909 if ($_[0] < 0) { 1021 if ($_[0] < 0) {
910 push @nondirs, $entry; 1022 push @nondirs, $entry;
911 } else { 1023 } else {
912 # need to check for real directory 1024 # need to check for real directory
913 aioreq_pri $pri; 1025 aioreq_pri $pri;
1026 $wd->[1] = $entry;
914 add $statgrp aio_lstat "$path/$entry", sub { 1027 add $statgrp aio_lstat $wd, sub {
915 if (-d _) { 1028 if (-d _) {
916 push @dirs, $entry; 1029 push @dirs, $entry;
917 1030
918 unless (--$ndirs) { 1031 unless (--$ndirs) {
919 push @nondirs, @$entries; 1032 push @nondirs, @$entries;
920 feed $statgrp; 1033 feed $statgrp;
1034 }
1035 } else {
1036 push @nondirs, $entry;
921 } 1037 }
922 } else {
923 push @nondirs, $entry;
924 } 1038 }
925 } 1039 }
926 } 1040 };
927 }; 1041 };
928 }; 1042 };
929 }; 1043 };
930 }; 1044 };
931 }; 1045 };
932 1046
933 $grp 1047 $grp
934} 1048}
935 1049
936=item aio_rmtree $path, $callback->($status) 1050=item aio_rmtree $pathname, $callback->($status)
937 1051
938Delete a directory tree starting (and including) C<$path>, return the 1052Delete a directory tree starting (and including) C<$path>, return the
939status of the final C<rmdir> only. This is a composite request that 1053status of the final C<rmdir> only. This is a composite request that
940uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1054uses C<aio_scandir> to recurse into and rmdir directories, and unlink
941everything else. 1055everything else.
… …
983callback with the fdatasync result code. 1097callback with the fdatasync result code.
984 1098
985If this call isn't available because your OS lacks it or it couldn't be 1099If this call isn't available because your OS lacks it or it couldn't be
986detected, it will be emulated by calling C<fsync> instead. 1100detected, it will be emulated by calling C<fsync> instead.
987 1101
1102=item aio_syncfs $fh, $callback->($status)
1103
1104Asynchronously call the syncfs syscall to sync the filesystem associated
1105to the given filehandle and call the callback with the syncfs result
1106code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1107errno to C<ENOSYS> nevertheless.
1108
988=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 1109=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
989 1110
990Sync the data portion of the file specified by C<$offset> and C<$length> 1111Sync the data portion of the file specified by C<$offset> and C<$length>
991to disk (but NOT the metadata), by calling the Linux-specific 1112to disk (but NOT the metadata), by calling the Linux-specific
992sync_file_range call. If sync_file_range is not available or it returns 1113sync_file_range call. If sync_file_range is not available or it returns
… …
995C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1116C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
996C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1117C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
997C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1118C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
998manpage for details. 1119manpage for details.
999 1120
1000=item aio_pathsync $path, $callback->($status) 1121=item aio_pathsync $pathname, $callback->($status)
1001 1122
1002This request tries to open, fsync and close the given path. This is a 1123This request tries to open, fsync and close the given path. This is a
1003composite request intended to sync directories after directory operations 1124composite request intended to sync directories after directory operations
1004(E.g. rename). This might not work on all operating systems or have any 1125(E.g. rename). This might not work on all operating systems or have any
1005specific effect, but usually it makes sure that directory changes get 1126specific effect, but usually it makes sure that directory changes get
… …
1039} 1160}
1040 1161
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1162=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1163
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1164This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1044scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note 1165scalars (see the C<IO::AIO::mmap> function, although it also works on data
1166scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1045that the scalar must only be modified in-place while an aio operation is 1167scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1168it).
1047 1169
1048It calls the C<msync> function of your OS, if available, with the memory 1170It calls the C<msync> function of your OS, if available, with the memory
1049area starting at C<$offset> in the string and ending C<$length> bytes 1171area starting at C<$offset> in the string and ending C<$length> bytes
1050later. If C<$length> is negative, counts from the end, and if C<$length> 1172later. If C<$length> is negative, counts from the end, and if C<$length>
1051is C<undef>, then it goes till the end of the string. The flags can be 1173is C<undef>, then it goes till the end of the string. The flags can be
… …
1062as for C<aio_msync>, above, except for flags, which must be either 1184as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1185C<0> (which reads all pages and ensures they are instantiated) or
1064C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1186C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1187writing an octet from it, which dirties the page).
1066 1188
1189=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1190
1191This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1192scalars.
1193
1194It reads in all the pages of the underlying storage into memory (if any)
1195and locks them, so they are not getting swapped/paged out or removed.
1196
1197If C<$length> is undefined, then the scalar will be locked till the end.
1198
1199On systems that do not implement C<mlock>, this function returns C<-1>
1200and sets errno to C<ENOSYS>.
1201
1202Note that the corresponding C<munlock> is synchronous and is
1203documented under L<MISCELLANEOUS FUNCTIONS>.
1204
1205Example: open a file, mmap and mlock it - both will be undone when
1206C<$data> gets destroyed.
1207
1208 open my $fh, "<", $path or die "$path: $!";
1209 my $data;
1210 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1211 aio_mlock $data; # mlock in background
1212
1213=item aio_mlockall $flags, $callback->($status)
1214
1215Calls the C<mlockall> function with the given C<$flags> (a combination of
1216C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1217
1218On systems that do not implement C<mlockall>, this function returns C<-1>
1219and sets errno to C<ENOSYS>.
1220
1221Note that the corresponding C<munlockall> is synchronous and is
1222documented under L<MISCELLANEOUS FUNCTIONS>.
1223
1224Example: asynchronously lock all current and future pages into memory.
1225
1226 aio_mlockall IO::AIO::MCL_FUTURE;
1227
1067=item aio_group $callback->(...) 1228=item aio_group $callback->(...)
1068 1229
1069This is a very special aio request: Instead of doing something, it is a 1230This is a very special aio request: Instead of doing something, it is a
1070container for other aio requests, which is useful if you want to bundle 1231container for other aio requests, which is useful if you want to bundle
1071many requests into a single, composite, request with a definite callback 1232many requests into a single, composite, request with a definite callback
… …
1107like sleep and file handle readable/writable, the overhead this creates is 1268like sleep and file handle readable/writable, the overhead this creates is
1108immense (it blocks a thread for a long time) so do not use this function 1269immense (it blocks a thread for a long time) so do not use this function
1109except to put your application under artificial I/O pressure. 1270except to put your application under artificial I/O pressure.
1110 1271
1111=back 1272=back
1273
1274
1275=head2 IO::AIO::WD - multiple working directories
1276
1277Your process only has one current working directory, which is used by all
1278threads. This makes it hard to use relative paths (some other component
1279could call C<chdir> at any time, and it is hard to control when the path
1280will be used by IO::AIO).
1281
1282One solution for this is to always use absolute paths. This usually works,
1283but can be quite slow (the kernel has to walk the whole path on every
1284access), and can also be a hassle to implement.
1285
1286Newer POSIX systems have a number of functions (openat, fdopendir,
1287futimensat and so on) that make it possible to specify working directories
1288per operation.
1289
1290For portability, and because the clowns who "designed", or shall I write,
1291perpetrated this new interface were obviously half-drunk, this abstraction
1292cannot be perfect, though.
1293
1294IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1295object. This object stores the canonicalised, absolute version of the
1296path, and on systems that allow it, also a directory file descriptor.
1297
1298Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1299or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1300object and a pathname instead. If the pathname is absolute, the
1301IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative
1302to that IO::AIO::WD object.
1303
1304For example, to get a wd object for F</etc> and then stat F<passwd>
1305inside, you would write:
1306
1307 aio_wd "/etc", sub {
1308 my $etcdir = shift;
1309
1310 # although $etcdir can be undef on error, there is generally no reason
1311 # to check for errors here, as aio_stat will fail with ENOENT
1312 # when $etcdir is undef.
1313
1314 aio_stat [$etcdir, "passwd"], sub {
1315 # yay
1316 };
1317 };
1318
1319This shows that creating an IO::AIO::WD object is itself a potentially
1320blocking operation, which is why it is done asynchronously.
1321
1322As with normal pathnames, IO::AIO keeps a copy of the working directory
1323object and the pathname string, so you could write the following without
1324causing any issues due to C<$path> getting reused:
1325
1326 my $path = [$wd, undef];
1327
1328 for my $name (qw(abc def ghi)) {
1329 $path->[1] = $name;
1330 aio_stat $path, sub {
1331 # ...
1332 };
1333 }
1334
1335There are some caveats: when directories get renamed (or deleted), the
1336pathname string doesn't change, so will point to the new directory (or
1337nowhere at all), while the directory fd, if available on the system,
1338will still point to the original directory. Most functions accepting a
1339pathname will use the directory fd on newer systems, and the string on
1340older systems. Some functions (such as realpath) will always rely on the
1341string form of the pathname.
1342
1343So this fucntionality is mainly useful to get some protection against
1344C<chdir>, to easily get an absolute path out of a relative path for future
1345reference, and to speed up doing many operations in the same directory
1346(e.g. when stat'ing all files in a directory).
1347
1348The following functions implement this working directory abstraction:
1349
1350=over 4
1351
1352=item aio_wd $pathname, $callback->($wd)
1353
1354Asynchonously canonicalise the given pathname and convert it to an
1355IO::AIO::WD object representing it. If possible and supported on the
1356system, also open a directory fd to speed up pathname resolution relative
1357to this working directory.
1358
1359If something goes wrong, then C<undef> is passwd to the callback instead
1360of a working directory object and C<$!> is set appropriately. Since
1361passing C<undef> as working directory component of a pathname fails the
1362request with C<ENOENT>, there is often no need for error checking in the
1363C<aio_wd> callback, as future requests using the value will fail in the
1364expected way.
1365
1366If this call isn't available because your OS lacks it or it couldn't be
1367detected, it will be emulated by calling C<fsync> instead.
1368
1369=item IO::AIO::CWD
1370
1371This is a compiletime constant (object) that represents the process
1372current working directory.
1373
1374Specifying this object as working directory object for a pathname is as
1375if the pathname would be specified directly, without a directory object,
1376e.g., these calls are functionally identical:
1377
1378 aio_stat "somefile", sub { ... };
1379 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1380
1381=back
1382
1112 1383
1113=head2 IO::AIO::REQ CLASS 1384=head2 IO::AIO::REQ CLASS
1114 1385
1115All non-aggregate C<aio_*> functions return an object of this class when 1386All non-aggregate C<aio_*> functions return an object of this class when
1116called in non-void context. 1387called in non-void context.
… …
1234 1505
1235Sets a feeder/generator on this group: every group can have an attached 1506Sets a feeder/generator on this group: every group can have an attached
1236generator that generates requests if idle. The idea behind this is that, 1507generator that generates requests if idle. The idea behind this is that,
1237although you could just queue as many requests as you want in a group, 1508although you could just queue as many requests as you want in a group,
1238this might starve other requests for a potentially long time. For example, 1509this might starve other requests for a potentially long time. For example,
1239C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1510C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1240delaying any later requests for a long time. 1511requests, delaying any later requests for a long time.
1241 1512
1242To avoid this, and allow incremental generation of requests, you can 1513To avoid this, and allow incremental generation of requests, you can
1243instead a group and set a feeder on it that generates those requests. The 1514instead a group and set a feeder on it that generates those requests. The
1244feed callback will be called whenever there are few enough (see C<limit>, 1515feed callback will be called whenever there are few enough (see C<limit>,
1245below) requests active in the group itself and is expected to queue more 1516below) requests active in the group itself and is expected to queue more
… …
1294 1565
1295See C<poll_cb> for an example. 1566See C<poll_cb> for an example.
1296 1567
1297=item IO::AIO::poll_cb 1568=item IO::AIO::poll_cb
1298 1569
1299Process some outstanding events on the result pipe. You have to call this 1570Process some outstanding events on the result pipe. You have to call
1300regularly. Returns C<0> if all events could be processed, or C<-1> if it 1571this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1572were no events to process), or C<-1> if it returned earlier for whatever
1302are outstanding. The amount of events processed depends on the settings of 1573reason. Returns immediately when no events are outstanding. The amount of
1303C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1574events processed depends on the settings of C<IO::AIO::max_poll_req> and
1575C<IO::AIO::max_poll_time>.
1304 1576
1305If not all requests were processed for whatever reason, the filehandle 1577If not all requests were processed for whatever reason, the filehandle
1306will still be ready when C<poll_cb> returns, so normally you don't have to 1578will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1579do anything special to have it called later.
1308 1580
1581Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1582ready, it can be beneficial to call this function from loops which submit
1583a lot of requests, to make sure the results get processed when they become
1584available and not just when the loop is finished and the event loop takes
1585over again. This function returns very fast when there are no outstanding
1586requests.
1587
1309Example: Install an Event watcher that automatically calls 1588Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1589IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1590SYNOPSIS section, at the top of this document):
1312 1591
1313 Event->io (fd => IO::AIO::poll_fileno, 1592 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1593 poll => 'r', async => 1,
1315 cb => \&IO::AIO::poll_cb); 1594 cb => \&IO::AIO::poll_cb);
1595
1596=item IO::AIO::poll_wait
1597
1598If there are any outstanding requests and none of them in the result
1599phase, wait till the result filehandle becomes ready for reading (simply
1600does a C<select> on the filehandle. This is useful if you want to
1601synchronously wait for some requests to finish).
1602
1603See C<nreqs> for an example.
1604
1605=item IO::AIO::poll
1606
1607Waits until some requests have been handled.
1608
1609Returns the number of requests processed, but is otherwise strictly
1610equivalent to:
1611
1612 IO::AIO::poll_wait, IO::AIO::poll_cb
1613
1614=item IO::AIO::flush
1615
1616Wait till all outstanding AIO requests have been handled.
1617
1618Strictly equivalent to:
1619
1620 IO::AIO::poll_wait, IO::AIO::poll_cb
1621 while IO::AIO::nreqs;
1316 1622
1317=item IO::AIO::max_poll_reqs $nreqs 1623=item IO::AIO::max_poll_reqs $nreqs
1318 1624
1319=item IO::AIO::max_poll_time $seconds 1625=item IO::AIO::max_poll_time $seconds
1320 1626
… …
1345 # use a low priority so other tasks have priority 1651 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1652 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1653 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1654 cb => &IO::AIO::poll_cb);
1349 1655
1350=item IO::AIO::poll_wait
1351
1352If there are any outstanding requests and none of them in the result
1353phase, wait till the result filehandle becomes ready for reading (simply
1354does a C<select> on the filehandle. This is useful if you want to
1355synchronously wait for some requests to finish).
1356
1357See C<nreqs> for an example.
1358
1359=item IO::AIO::poll
1360
1361Waits until some requests have been handled.
1362
1363Returns the number of requests processed, but is otherwise strictly
1364equivalent to:
1365
1366 IO::AIO::poll_wait, IO::AIO::poll_cb
1367
1368=item IO::AIO::flush
1369
1370Wait till all outstanding AIO requests have been handled.
1371
1372Strictly equivalent to:
1373
1374 IO::AIO::poll_wait, IO::AIO::poll_cb
1375 while IO::AIO::nreqs;
1376
1377=back 1656=back
1378 1657
1379=head3 CONTROLLING THE NUMBER OF THREADS 1658=head3 CONTROLLING THE NUMBER OF THREADS
1380 1659
1381=over 1660=over
… …
1414 1693
1415Under normal circumstances you don't need to call this function. 1694Under normal circumstances you don't need to call this function.
1416 1695
1417=item IO::AIO::max_idle $nthreads 1696=item IO::AIO::max_idle $nthreads
1418 1697
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1698Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1699(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1700timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1701C<$nthreads> other threads are also idle, it will free its resources and
1702exit.
1423 1703
1424This is useful when you allow a large number of threads (e.g. 100 or 1000) 1704This is useful when you allow a large number of threads (e.g. 100 or 1000)
1425to allow for extremely high load situations, but want to free resources 1705to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1706under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1707
1428The default is probably ok in most situations, especially if thread 1708The default is probably ok in most situations, especially if thread
1429creation is fast. If thread creation is very slow on your system you might 1709creation is fast. If thread creation is very slow on your system you might
1430want to use larger values. 1710want to use larger values.
1431 1711
1712=item IO::AIO::idle_timeout $seconds
1713
1714Sets the minimum idle timeout (default 10) after which worker threads are
1715allowed to exit. SEe C<IO::AIO::max_idle>.
1716
1432=item IO::AIO::max_outstanding $maxreqs 1717=item IO::AIO::max_outstanding $maxreqs
1718
1719Sets the maximum number of outstanding requests to C<$nreqs>. If
1720you do queue up more than this number of requests, the next call to
1721C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1722C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1723longer exceeded.
1724
1725In other words, this setting does not enforce a queue limit, but can be
1726used to make poll functions block if the limit is exceeded.
1433 1727
1434This is a very bad function to use in interactive programs because it 1728This is a very bad function to use in interactive programs because it
1435blocks, and a bad way to reduce concurrency because it is inexact: Better 1729blocks, and a bad way to reduce concurrency because it is inexact: Better
1436use an C<aio_group> together with a feed callback. 1730use an C<aio_group> together with a feed callback.
1437 1731
1438Sets the maximum number of outstanding requests to C<$nreqs>. If you 1732It's main use is in scripts without an event loop - when you want to stat
1439do queue up more than this number of requests, the next call to the 1733a lot of files, you can write somehting like this:
1440C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1441function will block until the limit is no longer exceeded.
1442 1734
1443The default value is very large, so there is no practical limit on the 1735 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1736
1446You can still queue as many requests as you want. Therefore, 1737 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1738 aio_stat $path , ...;
1448as a stop gap to shield against fatal memory overflow (with large values). 1739 IO::AIO::poll_cb;
1740 }
1741
1742 IO::AIO::flush;
1743
1744The call to C<poll_cb> inside the loop will normally return instantly, but
1745as soon as more thna C<32> reqeusts are in-flight, it will block until
1746some requests have been handled. This keeps the loop from pushing a large
1747number of C<aio_stat> requests onto the queue.
1748
1749The default value for C<max_outstanding> is very large, so there is no
1750practical limit on the number of outstanding requests.
1449 1751
1450=back 1752=back
1451 1753
1452=head3 STATISTICAL INFORMATION 1754=head3 STATISTICAL INFORMATION
1453 1755
… …
1491 1793
1492Returns the number of bytes copied, or C<-1> on error. 1794Returns the number of bytes copied, or C<-1> on error.
1493 1795
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1796=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1797
1496Simply calls the C<posix_fadvise> function (see it's 1798Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1799manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1800available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1801C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1802C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1803
1502On systems that do not implement C<posix_fadvise>, this function returns 1804On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1805ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 1806
1505=item IO::AIO::mlockall $flags 1807=item IO::AIO::madvise $scalar, $offset, $len, $advice
1506 1808
1507Calls the C<mlockall> function with the given C<$flags> (a combination of 1809Simply calls the C<posix_madvise> function (see its
1508C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>). 1810manpage for details). The following advice constants are
1811available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1812C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1509 1813
1814On systems that do not implement C<posix_madvise>, this function returns
1815ENOSYS, otherwise the return value of C<posix_madvise>.
1816
1817=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1818
1819Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1820$scalar (see its manpage for details). The following protect
1821constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1822C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1823
1510On systems that do not implement C<mlockall>, this function returns 1824On systems that do not implement C<mprotect>, this function returns
1511ENOSYS, otherwise the return value of C<mlockall>. 1825ENOSYS, otherwise the return value of C<mprotect>.
1826
1827=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1828
1829Memory-maps a file (or anonymous memory range) and attaches it to the
1830given C<$scalar>, which will act like a string scalar.
1831
1832The only operations allowed on the scalar are C<substr>/C<vec> that don't
1833change the string length, and most read-only operations such as copying it
1834or searching it with regexes and so on.
1835
1836Anything else is unsafe and will, at best, result in memory leaks.
1837
1838The memory map associated with the C<$scalar> is automatically removed
1839when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1840C<IO::AIO::munmap> functions are called.
1841
1842This calls the C<mmap>(2) function internally. See your system's manual
1843page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1844
1845The C<$length> must be larger than zero and smaller than the actual
1846filesize.
1847
1848C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1849C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1850
1851C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1852C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1853not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1854(which is set to C<MAP_ANON> if your system only provides this
1855constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1856C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1857C<IO::AIO::MAP_NONBLOCK>
1858
1859If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1860
1861C<$offset> is the offset from the start of the file - it generally must be
1862a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1863
1864Example:
1865
1866 use Digest::MD5;
1867 use IO::AIO;
1868
1869 open my $fh, "<verybigfile"
1870 or die "$!";
1871
1872 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1873 or die "verybigfile: $!";
1874
1875 my $fast_md5 = md5 $data;
1876
1877=item IO::AIO::munmap $scalar
1878
1879Removes a previous mmap and undefines the C<$scalar>.
1880
1881=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1882
1883Calls the C<munlock> function, undoing the effects of a previous
1884C<aio_mlock> call (see its description for details).
1512 1885
1513=item IO::AIO::munlockall 1886=item IO::AIO::munlockall
1514 1887
1515Calls the C<munlockall> function. 1888Calls the C<munlockall> function.
1516 1889
… …
1525 1898
1526END { flush } 1899END { flush }
1527 1900
15281; 19011;
1529 1902
1903=head1 EVENT LOOP INTEGRATION
1904
1905It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1906automatically into many event loops:
1907
1908 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1909 use AnyEvent::AIO;
1910
1911You can also integrate IO::AIO manually into many event loops, here are
1912some examples of how to do this:
1913
1914 # EV integration
1915 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1916
1917 # Event integration
1918 Event->io (fd => IO::AIO::poll_fileno,
1919 poll => 'r',
1920 cb => \&IO::AIO::poll_cb);
1921
1922 # Glib/Gtk2 integration
1923 add_watch Glib::IO IO::AIO::poll_fileno,
1924 in => sub { IO::AIO::poll_cb; 1 };
1925
1926 # Tk integration
1927 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1928 readable => \&IO::AIO::poll_cb);
1929
1930 # Danga::Socket integration
1931 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1932 \&IO::AIO::poll_cb);
1933
1530=head2 FORK BEHAVIOUR 1934=head2 FORK BEHAVIOUR
1531 1935
1532This module should do "the right thing" when the process using it forks: 1936Usage of pthreads in a program changes the semantics of fork
1937considerably. Specifically, only async-safe functions can be called after
1938fork. Perl doesn't know about this, so in general, you cannot call fork
1939with defined behaviour in perl if pthreads are involved. IO::AIO uses
1940pthreads, so this applies, but many other extensions and (for inexplicable
1941reasons) perl itself often is linked against pthreads, so this limitation
1942applies to quite a lot of perls.
1533 1943
1534Before the fork, IO::AIO enters a quiescent state where no requests 1944This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1535can be added in other threads and no results will be processed. After 1945only works in the process that loaded it. Forking is fully supported, but
1536the fork the parent simply leaves the quiescent state and continues 1946using IO::AIO in the child is not.
1537request/result processing, while the child frees the request/result queue
1538(so that the requests started before the fork will only be handled in the
1539parent). Threads will be started on demand until the limit set in the
1540parent process has been reached again.
1541 1947
1542In short: the parent will, after a short pause, continue as if fork had 1948You might get around by not I<using> IO::AIO before (or after)
1543not been called, while the child will act as if IO::AIO has not been used 1949forking. You could also try to call the L<IO::AIO::reinit> function in the
1544yet. 1950child:
1951
1952=over 4
1953
1954=item IO::AIO::reinit
1955
1956Abandons all current requests and I/O threads and simply reinitialises all
1957data structures. This is not an operation supported by any standards, but
1958happens to work on GNU/Linux and some newer BSD systems.
1959
1960The only reasonable use for this function is to call it after forking, if
1961C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
1962the process will result in undefined behaviour. Calling it at any time
1963will also result in any undefined (by POSIX) behaviour.
1964
1965=back
1545 1966
1546=head2 MEMORY USAGE 1967=head2 MEMORY USAGE
1547 1968
1548Per-request usage: 1969Per-request usage:
1549 1970

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