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Revision 1.152 by root, Fri Jun 12 16:48:08 2009 UTC vs.
Revision 1.195 by root, Fri May 27 19:56:31 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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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 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $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
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. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
58 36
59Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This 39will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even 40is extremely useful for programs that need to stay interactive even
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66on a RAID volume or over NFS when you do a number of stat operations 44on a RAID volume or over NFS when you do a number of stat operations
67concurrently. 45concurrently.
68 46
69While most of this works on all types of file descriptors (for 47While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that 48example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very 49support nonblocking operation (again, sockets, pipes etc.) is
72inefficient. Use an event loop for that (such as the L<Event|Event> 50very inefficient. Use an event loop for that (such as the L<EV>
73module): IO::AIO will naturally fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
74 52
75In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
76requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
77in perl, and the threads created by this module will not be visible 55in perl, and the threads created by this module will not be visible
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87yourself, always call C<poll_cb> from within the same thread, or never 65yourself, always call C<poll_cb> from within the same thread, or never
88call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
89 67
90=head2 EXAMPLE 68=head2 EXAMPLE
91 69
92This is a simple example that uses the Event module and loads 70This is a simple example that uses the EV module and loads
93F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
94 72
95 use Fcntl; 73 use Fcntl;
96 use Event; 74 use EV;
97 use IO::AIO; 75 use IO::AIO;
98 76
99 # register the IO::AIO callback with Event 77 # register the IO::AIO callback with EV
100 Event->io (fd => IO::AIO::poll_fileno, 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103 79
104 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
106 my $fh = shift 82 my $fh = shift
107 or die "error while opening: $!"; 83 or die "error while opening: $!";
108 84
109 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
110 my $size = -s $fh; 86 my $size = -s $fh;
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119 95
120 # file contents now in $contents 96 # file contents now in $contents
121 print $contents; 97 print $contents;
122 98
123 # exit event loop and program 99 # exit event loop and program
124 Event::unloop; 100 EV::unloop;
125 }; 101 };
126 }; 102 };
127 103
128 # possibly queue up other requests, or open GUI windows, 104 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc. 105 # check for sockets etc. etc.
130 106
131 # process events as long as there are some: 107 # process events as long as there are some:
132 Event::loop; 108 EV::loop;
133 109
134=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
135 111
136Every C<aio_*> function creates a request. which is a C data structure not 112Every C<aio_*> function creates a request. which is a C data structure not
137directly visible to Perl. 113directly visible to Perl.
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187 163
188package IO::AIO; 164package IO::AIO;
189 165
190use Carp (); 166use Carp ();
191 167
192no warnings; 168use common::sense;
193use strict 'vars';
194 169
195use base 'Exporter'; 170use base 'Exporter';
196 171
197BEGIN { 172BEGIN {
198 our $VERSION = '3.21'; 173 our $VERSION = '3.9';
199 174
200 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
201 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
202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
203 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
204 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
205 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 180 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
206 aio_chmod aio_utime aio_truncate); 181 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs);
207 184
208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210 min_parallel max_parallel max_idle 187 min_parallel max_parallel max_idle idle_timeout
211 nreqs nready npending nthreads 188 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs); 189 max_poll_time max_poll_reqs
190 sendfile fadvise madvise
191 mmap munmap munlock munlockall);
213 192
214 push @AIO_REQ, qw(aio_busy); # not exported 193 push @AIO_REQ, qw(aio_busy); # not exported
215 194
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 196
218 require XSLoader; 197 require XSLoader;
219 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
220} 199}
221 200
222=head1 FUNCTIONS 201=head1 FUNCTIONS
202
203=head2 QUICK OVERVIEW
204
205This section simply lists the prototypes of the most important functions
206for quick reference. See the following sections for function-by-function
207documentation.
208
209 aio_open $pathname, $flags, $mode, $callback->($fh)
210 aio_close $fh, $callback->($status)
211 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214 aio_readahead $fh,$offset,$length, $callback->($retval)
215 aio_stat $fh_or_path, $callback->($status)
216 aio_lstat $fh, $callback->($status)
217 aio_statvfs $fh_or_path, $callback->($statvfs)
218 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
220 aio_truncate $fh_or_path, $offset, $callback->($status)
221 aio_chmod $fh_or_path, $mode, $callback->($status)
222 aio_unlink $pathname, $callback->($status)
223 aio_mknod $path, $mode, $dev, $callback->($status)
224 aio_link $srcpath, $dstpath, $callback->($status)
225 aio_symlink $srcpath, $dstpath, $callback->($status)
226 aio_readlink $path, $callback->($link)
227 aio_rename $srcpath, $dstpath, $callback->($status)
228 aio_mkdir $pathname, $mode, $callback->($status)
229 aio_rmdir $pathname, $callback->($status)
230 aio_readdir $pathname, $callback->($entries)
231 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
234 aio_load $path, $data, $callback->($status)
235 aio_copy $srcpath, $dstpath, $callback->($status)
236 aio_move $srcpath, $dstpath, $callback->($status)
237 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238 aio_rmtree $path, $callback->($status)
239 aio_sync $callback->($status)
240 aio_fsync $fh, $callback->($status)
241 aio_fdatasync $fh, $callback->($status)
242 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243 aio_pathsync $path, $callback->($status)
244 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247 aio_mlockall $flags, $callback->($status)
248 aio_group $callback->(...)
249 aio_nop $callback->()
250
251 $prev_pri = aioreq_pri [$pri]
252 aioreq_nice $pri_adjust
253
254 IO::AIO::poll_wait
255 IO::AIO::poll_cb
256 IO::AIO::poll
257 IO::AIO::flush
258 IO::AIO::max_poll_reqs $nreqs
259 IO::AIO::max_poll_time $seconds
260 IO::AIO::min_parallel $nthreads
261 IO::AIO::max_parallel $nthreads
262 IO::AIO::max_idle $nthreads
263 IO::AIO::idle_timeout $seconds
264 IO::AIO::max_outstanding $maxreqs
265 IO::AIO::nreqs
266 IO::AIO::nready
267 IO::AIO::npending
268
269 IO::AIO::sendfile $ofh, $ifh, $offset, $count
270 IO::AIO::fadvise $fh, $offset, $len, $advice
271 IO::AIO::madvise $scalar, $offset, $length, $advice
272 IO::AIO::mprotect $scalar, $offset, $length, $protect
273 IO::AIO::munlock $scalar, $offset = 0, $length = undef
274 IO::AIO::munlockall
223 275
224=head2 AIO REQUEST FUNCTIONS 276=head2 AIO REQUEST FUNCTIONS
225 277
226All the C<aio_*> calls are more or less thin wrappers around the syscall 278All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 279with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 359by the umask in effect then the request is being executed, so better never
308change the umask. 360change the umask.
309 361
310Example: 362Example:
311 363
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 364 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 365 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 366 print "open successful, fh is $_[0]\n";
315 ... 367 ...
316 } else { 368 } else {
317 die "open failed: $!\n"; 369 die "open failed: $!\n";
318 } 370 }
319 }; 371 };
320 372
373In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
374C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
375following POSIX and non-POSIX constants are available (missing ones on
376your system are, as usual, C<0>):
377
378C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
379C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
380C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
381
321 382
322=item aio_close $fh, $callback->($status) 383=item aio_close $fh, $callback->($status)
323 384
324Asynchronously close a file and call the callback with the result 385Asynchronously close a file and call the callback with the result
325code. 386code.
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377reading at byte offset C<$in_offset>, and starts writing at the current 438reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 439file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 440than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 441other.
381 442
443Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
444are written, and there is no way to find out how many bytes have been read
445from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
446bytes written to C<$out_fh>. Only if the result value equals C<$length>
447one can assume that C<$length> bytes have been read.
448
449Unlike with other C<aio_> functions, it makes a lot of sense to use
450C<aio_sendfile> on non-blocking sockets, as long as one end (typically
451the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
452the socket I/O will be non-blocking. Note, however, that you can run into
453a trap where C<aio_sendfile> reads some data with readahead, then fails
454to write all data, and when the socket is ready the next time, the data
455in the cache is already lost, forcing C<aio_sendfile> to again hit the
456disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
457much better.
458
382This call tries to make use of a native C<sendfile> syscall to provide 459This call tries to make use of a native C<sendfile> syscall to provide
383zero-copy operation. For this to work, C<$out_fh> should refer to a 460zero-copy operation. For this to work, C<$out_fh> should refer to a
384socket, and C<$in_fh> should refer to mmap'able file. 461socket, and C<$in_fh> should refer to an mmap'able file.
385 462
386If the native sendfile call fails or is not implemented, it will be 463If a native sendfile cannot be found or it fails with C<ENOSYS>,
464C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
387emulated, so you can call C<aio_sendfile> on any type of filehandle 465it will be emulated, so you can call C<aio_sendfile> on any type of
388regardless of the limitations of the operating system. 466filehandle regardless of the limitations of the operating system.
389
390Please note, however, that C<aio_sendfile> can read more bytes from
391C<$in_fh> than are written, and there is no way to find out how many
392bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
393provides the number of bytes written to C<$out_fh>. Only if the result
394value equals C<$length> one can assume that C<$length> bytes have been
395read.
396 467
397 468
398=item aio_readahead $fh,$offset,$length, $callback->($retval) 469=item aio_readahead $fh,$offset,$length, $callback->($retval)
399 470
400C<aio_readahead> populates the page cache with data from a file so that 471C<aio_readahead> populates the page cache with data from a file so that
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423 494
424Currently, the stats are always 64-bit-stats, i.e. instead of returning an 495Currently, the stats are always 64-bit-stats, i.e. instead of returning an
425error when stat'ing a large file, the results will be silently truncated 496error when stat'ing a large file, the results will be silently truncated
426unless perl itself is compiled with large file support. 497unless perl itself is compiled with large file support.
427 498
499To help interpret the mode and dev/rdev stat values, IO::AIO offers the
500following constants and functions (if not implemented, the constants will
501be C<0> and the functions will either C<croak> or fall back on traditional
502behaviour).
503
504C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
505C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
506C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
507
428Example: Print the length of F</etc/passwd>: 508Example: Print the length of F</etc/passwd>:
429 509
430 aio_stat "/etc/passwd", sub { 510 aio_stat "/etc/passwd", sub {
431 $_[0] and die "stat failed: $!"; 511 $_[0] and die "stat failed: $!";
432 print "size is ", -s _, "\n"; 512 print "size is ", -s _, "\n";
433 }; 513 };
434 514
435 515
516=item aio_statvfs $fh_or_path, $callback->($statvfs)
517
518Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
519whether a file handle or path was passed.
520
521On success, the callback is passed a hash reference with the following
522members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
523C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
524is passed.
525
526The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
527C<ST_NOSUID>.
528
529The following non-POSIX IO::AIO::ST_* flag masks are defined to
530their correct value when available, or to C<0> on systems that do
531not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
532C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
533C<ST_NODIRATIME> and C<ST_RELATIME>.
534
535Example: stat C</wd> and dump out the data if successful.
536
537 aio_statvfs "/wd", sub {
538 my $f = $_[0]
539 or die "statvfs: $!";
540
541 use Data::Dumper;
542 say Dumper $f;
543 };
544
545 # result:
546 {
547 bsize => 1024,
548 bfree => 4333064312,
549 blocks => 10253828096,
550 files => 2050765568,
551 flag => 4096,
552 favail => 2042092649,
553 bavail => 4333064312,
554 ffree => 2042092649,
555 namemax => 255,
556 frsize => 1024,
557 fsid => 1810
558 }
559
560
436=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 561=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
437 562
438Works like perl's C<utime> function (including the special case of $atime 563Works like perl's C<utime> function (including the special case of $atime
439and $mtime being undef). Fractional times are supported if the underlying 564and $mtime being undef). Fractional times are supported if the underlying
440syscalls support them. 565syscalls support them.
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488 613
489The only (POSIX-) portable way of calling this function is: 614The only (POSIX-) portable way of calling this function is:
490 615
491 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 616 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
492 617
618See C<aio_stat> for info about some potentially helpful extra constants
619and functions.
493 620
494=item aio_link $srcpath, $dstpath, $callback->($status) 621=item aio_link $srcpath, $dstpath, $callback->($status)
495 622
496Asynchronously create a new link to the existing object at C<$srcpath> at 623Asynchronously create a new link to the existing object at C<$srcpath> at
497the path C<$dstpath> and call the callback with the result code. 624the path C<$dstpath> and call the callback with the result code.
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550 677
551=over 4 678=over 4
552 679
553=item IO::AIO::READDIR_DENTS 680=item IO::AIO::READDIR_DENTS
554 681
555When this flag is off, then the callback gets an arrayref with of names 682When this flag is off, then the callback gets an arrayref consisting of
556only (as with C<aio_readdir>), otherwise it gets an arrayref with 683names only (as with C<aio_readdir>), otherwise it gets an arrayref with
557C<[$name, $type, $inode]> arrayrefs, each describing a single directory 684C<[$name, $type, $inode]> arrayrefs, each describing a single directory
558entry in more detail. 685entry in more detail.
559 686
560C<$name> is the name of the entry. 687C<$name> is the name of the entry.
561 688
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568C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 695C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
569know, you have to run stat yourself. Also, for speed reasons, the C<$type> 696know, you have to run stat yourself. Also, for speed reasons, the C<$type>
570scalars are read-only: you can not modify them. 697scalars are read-only: you can not modify them.
571 698
572C<$inode> is the inode number (which might not be exact on systems with 64 699C<$inode> is the inode number (which might not be exact on systems with 64
573bit inode numbers and 32 bit perls). On systems that do not deliver the 700bit inode numbers and 32 bit perls). This field has unspecified content on
574inode information, this will always be zero. 701systems that do not deliver the inode information.
575 702
576=item IO::AIO::READDIR_DIRS_FIRST 703=item IO::AIO::READDIR_DIRS_FIRST
577 704
578When this flag is set, then the names will be returned in an order where 705When this flag is set, then the names will be returned in an order where
579likely directories come first. This is useful when you need to quickly 706likely directories come first, in optimal stat order. This is useful when
580find directories, or you want to find all directories while avoiding to 707you need to quickly find directories, or you want to find all directories
581stat() each entry. 708while avoiding to stat() each entry.
582 709
583If the system returns type information in readdir, then this is used 710If the system returns type information in readdir, then this is used
584to find directories directly. Otherwise, likely directories are files 711to find directories directly. Otherwise, likely directories are names
585beginning with ".", or otherwise files with no dots, of which files with 712beginning with ".", or otherwise names with no dots, of which names with
586short names are tried first. 713short names are tried first.
587 714
588=item IO::AIO::READDIR_STAT_ORDER 715=item IO::AIO::READDIR_STAT_ORDER
589 716
590When this flag is set, then the names will be returned in an order 717When this flag is set, then the names will be returned in an order
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635 762
636=item aio_copy $srcpath, $dstpath, $callback->($status) 763=item aio_copy $srcpath, $dstpath, $callback->($status)
637 764
638Try to copy the I<file> (directories not supported as either source or 765Try to copy the I<file> (directories not supported as either source or
639destination) from C<$srcpath> to C<$dstpath> and call the callback with 766destination) from C<$srcpath> to C<$dstpath> and call the callback with
640the C<0> (error) or C<-1> ok. 767a status of C<0> (ok) or C<-1> (error, see C<$!>).
641 768
642This is a composite request that creates the destination file with 769This is a composite request that creates the destination file with
643mode 0200 and copies the contents of the source file into it using 770mode 0200 and copies the contents of the source file into it using
644C<aio_sendfile>, followed by restoring atime, mtime, access mode and 771C<aio_sendfile>, followed by restoring atime, mtime, access mode and
645uid/gid, in that order. 772uid/gid, in that order.
… …
657 my $grp = aio_group $cb; 784 my $grp = aio_group $cb;
658 785
659 aioreq_pri $pri; 786 aioreq_pri $pri;
660 add $grp aio_open $src, O_RDONLY, 0, sub { 787 add $grp aio_open $src, O_RDONLY, 0, sub {
661 if (my $src_fh = $_[0]) { 788 if (my $src_fh = $_[0]) {
662 my @stat = stat $src_fh; # hmm, might bock over nfs? 789 my @stat = stat $src_fh; # hmm, might block over nfs?
663 790
664 aioreq_pri $pri; 791 aioreq_pri $pri;
665 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 792 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
666 if (my $dst_fh = $_[0]) { 793 if (my $dst_fh = $_[0]) {
667 aioreq_pri $pri; 794 aioreq_pri $pri;
… …
714 841
715=item aio_move $srcpath, $dstpath, $callback->($status) 842=item aio_move $srcpath, $dstpath, $callback->($status)
716 843
717Try to move the I<file> (directories not supported as either source or 844Try to move the I<file> (directories not supported as either source or
718destination) from C<$srcpath> to C<$dstpath> and call the callback with 845destination) from C<$srcpath> to C<$dstpath> and call the callback with
719the C<0> (error) or C<-1> ok. 846a status of C<0> (ok) or C<-1> (error, see C<$!>).
720 847
721This is a composite request that tries to rename(2) the file first; if 848This is a composite request that tries to rename(2) the file first; if
722rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if 849rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
723that is successful, unlinks the C<$srcpath>. 850that is successful, unlinks the C<$srcpath>.
724 851
… …
958(E.g. rename). This might not work on all operating systems or have any 1085(E.g. rename). This might not work on all operating systems or have any
959specific effect, but usually it makes sure that directory changes get 1086specific effect, but usually it makes sure that directory changes get
960written to disc. It works for anything that can be opened for read-only, 1087written to disc. It works for anything that can be opened for read-only,
961not just directories. 1088not just directories.
962 1089
1090Future versions of this function might fall back to other methods when
1091C<fsync> on the directory fails (such as calling C<sync>).
1092
963Passes C<0> when everything went ok, and C<-1> on error. 1093Passes C<0> when everything went ok, and C<-1> on error.
964 1094
965=cut 1095=cut
966 1096
967sub aio_pathsync($;$) { 1097sub aio_pathsync($;$) {
… …
987 }; 1117 };
988 1118
989 $grp 1119 $grp
990} 1120}
991 1121
1122=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1123
1124This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1125scalars (see the C<IO::AIO::mmap> function, although it also works on data
1126scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1127scalar must only be modified in-place while an aio operation is pending on
1128it).
1129
1130It calls the C<msync> function of your OS, if available, with the memory
1131area starting at C<$offset> in the string and ending C<$length> bytes
1132later. If C<$length> is negative, counts from the end, and if C<$length>
1133is C<undef>, then it goes till the end of the string. The flags can be
1134a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1135C<IO::AIO::MS_SYNC>.
1136
1137=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1138
1139This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1140scalars.
1141
1142It touches (reads or writes) all memory pages in the specified
1143range inside the scalar. All caveats and parameters are the same
1144as for C<aio_msync>, above, except for flags, which must be either
1145C<0> (which reads all pages and ensures they are instantiated) or
1146C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1147writing an octet from it, which dirties the page).
1148
1149=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1150
1151This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1152scalars.
1153
1154It reads in all the pages of the underlying storage into memory (if any)
1155and locks them, so they are not getting swapped/paged out or removed.
1156
1157If C<$length> is undefined, then the scalar will be locked till the end.
1158
1159On systems that do not implement C<mlock>, this function returns C<-1>
1160and sets errno to C<ENOSYS>.
1161
1162Note that the corresponding C<munlock> is synchronous and is
1163documented under L<MISCELLANEOUS FUNCTIONS>.
1164
1165Example: open a file, mmap and mlock it - both will be undone when
1166C<$data> gets destroyed.
1167
1168 open my $fh, "<", $path or die "$path: $!";
1169 my $data;
1170 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1171 aio_mlock $data; # mlock in background
1172
1173=item aio_mlockall $flags, $callback->($status)
1174
1175Calls the C<mlockall> function with the given C<$flags> (a combination of
1176C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1177
1178On systems that do not implement C<mlockall>, this function returns C<-1>
1179and sets errno to C<ENOSYS>.
1180
1181Note that the corresponding C<munlockall> is synchronous and is
1182documented under L<MISCELLANEOUS FUNCTIONS>.
1183
1184Example: asynchronously lock all current and future pages into memory.
1185
1186 aio_mlockall IO::AIO::MCL_FUTURE;
1187
992=item aio_group $callback->(...) 1188=item aio_group $callback->(...)
993 1189
994This is a very special aio request: Instead of doing something, it is a 1190This is a very special aio request: Instead of doing something, it is a
995container for other aio requests, which is useful if you want to bundle 1191container for other aio requests, which is useful if you want to bundle
996many requests into a single, composite, request with a definite callback 1192many requests into a single, composite, request with a definite callback
… …
1131=item $grp->cancel_subs 1327=item $grp->cancel_subs
1132 1328
1133Cancel all subrequests and clears any feeder, but not the group request 1329Cancel all subrequests and clears any feeder, but not the group request
1134itself. Useful when you queued a lot of events but got a result early. 1330itself. Useful when you queued a lot of events but got a result early.
1135 1331
1332The group request will finish normally (you cannot add requests to the
1333group).
1334
1136=item $grp->result (...) 1335=item $grp->result (...)
1137 1336
1138Set the result value(s) that will be passed to the group callback when all 1337Set the result value(s) that will be passed to the group callback when all
1139subrequests have finished and set the groups errno to the current value 1338subrequests have finished and set the groups errno to the current value
1140of errno (just like calling C<errno> without an error number). By default, 1339of errno (just like calling C<errno> without an error number). By default,
… …
1208=over 4 1407=over 4
1209 1408
1210=item $fileno = IO::AIO::poll_fileno 1409=item $fileno = IO::AIO::poll_fileno
1211 1410
1212Return the I<request result pipe file descriptor>. This filehandle must be 1411Return the I<request result pipe file descriptor>. This filehandle must be
1213polled for reading by some mechanism outside this module (e.g. Event or 1412polled for reading by some mechanism outside this module (e.g. EV, Glib,
1214select, see below or the SYNOPSIS). If the pipe becomes readable you have 1413select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1215to call C<poll_cb> to check the results. 1414you have to call C<poll_cb> to check the results.
1216 1415
1217See C<poll_cb> for an example. 1416See C<poll_cb> for an example.
1218 1417
1219=item IO::AIO::poll_cb 1418=item IO::AIO::poll_cb
1220 1419
1221Process some outstanding events on the result pipe. You have to call this 1420Process some outstanding events on the result pipe. You have to call
1222regularly. Returns C<0> if all events could be processed, or C<-1> if it 1421this regularly. Returns C<0> if all events could be processed (or there
1223returned earlier for whatever reason. Returns immediately when no events 1422were no events to process), or C<-1> if it returned earlier for whatever
1224are outstanding. The amount of events processed depends on the settings of 1423reason. Returns immediately when no events are outstanding. The amount of
1225C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1424events processed depends on the settings of C<IO::AIO::max_poll_req> and
1425C<IO::AIO::max_poll_time>.
1226 1426
1227If not all requests were processed for whatever reason, the filehandle 1427If not all requests were processed for whatever reason, the filehandle
1228will still be ready when C<poll_cb> returns, so normally you don't have to 1428will still be ready when C<poll_cb> returns, so normally you don't have to
1229do anything special to have it called later. 1429do anything special to have it called later.
1230 1430
1431Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1432ready, it can be beneficial to call this function from loops which submit
1433a lot of requests, to make sure the results get processed when they become
1434available and not just when the loop is finished and the event loop takes
1435over again. This function returns very fast when there are no outstanding
1436requests.
1437
1231Example: Install an Event watcher that automatically calls 1438Example: Install an Event watcher that automatically calls
1232IO::AIO::poll_cb with high priority: 1439IO::AIO::poll_cb with high priority (more examples can be found in the
1440SYNOPSIS section, at the top of this document):
1233 1441
1234 Event->io (fd => IO::AIO::poll_fileno, 1442 Event->io (fd => IO::AIO::poll_fileno,
1235 poll => 'r', async => 1, 1443 poll => 'r', async => 1,
1236 cb => \&IO::AIO::poll_cb); 1444 cb => \&IO::AIO::poll_cb);
1445
1446=item IO::AIO::poll_wait
1447
1448If there are any outstanding requests and none of them in the result
1449phase, wait till the result filehandle becomes ready for reading (simply
1450does a C<select> on the filehandle. This is useful if you want to
1451synchronously wait for some requests to finish).
1452
1453See C<nreqs> for an example.
1454
1455=item IO::AIO::poll
1456
1457Waits until some requests have been handled.
1458
1459Returns the number of requests processed, but is otherwise strictly
1460equivalent to:
1461
1462 IO::AIO::poll_wait, IO::AIO::poll_cb
1463
1464=item IO::AIO::flush
1465
1466Wait till all outstanding AIO requests have been handled.
1467
1468Strictly equivalent to:
1469
1470 IO::AIO::poll_wait, IO::AIO::poll_cb
1471 while IO::AIO::nreqs;
1237 1472
1238=item IO::AIO::max_poll_reqs $nreqs 1473=item IO::AIO::max_poll_reqs $nreqs
1239 1474
1240=item IO::AIO::max_poll_time $seconds 1475=item IO::AIO::max_poll_time $seconds
1241 1476
… …
1266 # use a low priority so other tasks have priority 1501 # use a low priority so other tasks have priority
1267 Event->io (fd => IO::AIO::poll_fileno, 1502 Event->io (fd => IO::AIO::poll_fileno,
1268 poll => 'r', nice => 1, 1503 poll => 'r', nice => 1,
1269 cb => &IO::AIO::poll_cb); 1504 cb => &IO::AIO::poll_cb);
1270 1505
1271=item IO::AIO::poll_wait
1272
1273If there are any outstanding requests and none of them in the result
1274phase, wait till the result filehandle becomes ready for reading (simply
1275does a C<select> on the filehandle. This is useful if you want to
1276synchronously wait for some requests to finish).
1277
1278See C<nreqs> for an example.
1279
1280=item IO::AIO::poll
1281
1282Waits until some requests have been handled.
1283
1284Returns the number of requests processed, but is otherwise strictly
1285equivalent to:
1286
1287 IO::AIO::poll_wait, IO::AIO::poll_cb
1288
1289=item IO::AIO::flush
1290
1291Wait till all outstanding AIO requests have been handled.
1292
1293Strictly equivalent to:
1294
1295 IO::AIO::poll_wait, IO::AIO::poll_cb
1296 while IO::AIO::nreqs;
1297
1298=back 1506=back
1299 1507
1300=head3 CONTROLLING THE NUMBER OF THREADS 1508=head3 CONTROLLING THE NUMBER OF THREADS
1301 1509
1302=over 1510=over
… …
1335 1543
1336Under normal circumstances you don't need to call this function. 1544Under normal circumstances you don't need to call this function.
1337 1545
1338=item IO::AIO::max_idle $nthreads 1546=item IO::AIO::max_idle $nthreads
1339 1547
1340Limit the number of threads (default: 4) that are allowed to idle (i.e., 1548Limit the number of threads (default: 4) that are allowed to idle
1341threads that did not get a request to process within 10 seconds). That 1549(i.e., threads that did not get a request to process within the idle
1342means if a thread becomes idle while C<$nthreads> other threads are also 1550timeout (default: 10 seconds). That means if a thread becomes idle while
1343idle, it will free its resources and exit. 1551C<$nthreads> other threads are also idle, it will free its resources and
1552exit.
1344 1553
1345This is useful when you allow a large number of threads (e.g. 100 or 1000) 1554This is useful when you allow a large number of threads (e.g. 100 or 1000)
1346to allow for extremely high load situations, but want to free resources 1555to allow for extremely high load situations, but want to free resources
1347under normal circumstances (1000 threads can easily consume 30MB of RAM). 1556under normal circumstances (1000 threads can easily consume 30MB of RAM).
1348 1557
1349The default is probably ok in most situations, especially if thread 1558The default is probably ok in most situations, especially if thread
1350creation is fast. If thread creation is very slow on your system you might 1559creation is fast. If thread creation is very slow on your system you might
1351want to use larger values. 1560want to use larger values.
1352 1561
1562=item IO::AIO::idle_timeout $seconds
1563
1564Sets the minimum idle timeout (default 10) after which worker threads are
1565allowed to exit. SEe C<IO::AIO::max_idle>.
1566
1353=item IO::AIO::max_outstanding $maxreqs 1567=item IO::AIO::max_outstanding $maxreqs
1568
1569Sets the maximum number of outstanding requests to C<$nreqs>. If
1570you do queue up more than this number of requests, the next call to
1571C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1572C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1573longer exceeded.
1574
1575In other words, this setting does not enforce a queue limit, but can be
1576used to make poll functions block if the limit is exceeded.
1354 1577
1355This is a very bad function to use in interactive programs because it 1578This is a very bad function to use in interactive programs because it
1356blocks, and a bad way to reduce concurrency because it is inexact: Better 1579blocks, and a bad way to reduce concurrency because it is inexact: Better
1357use an C<aio_group> together with a feed callback. 1580use an C<aio_group> together with a feed callback.
1358 1581
1359Sets the maximum number of outstanding requests to C<$nreqs>. If you 1582It's main use is in scripts without an event loop - when you want to stat
1360do queue up more than this number of requests, the next call to the 1583a lot of files, you can write somehting like this:
1361C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1362function will block until the limit is no longer exceeded.
1363 1584
1364The default value is very large, so there is no practical limit on the 1585 IO::AIO::max_outstanding 32;
1365number of outstanding requests.
1366 1586
1367You can still queue as many requests as you want. Therefore, 1587 for my $path (...) {
1368C<max_outstanding> is mainly useful in simple scripts (with low values) or 1588 aio_stat $path , ...;
1369as a stop gap to shield against fatal memory overflow (with large values). 1589 IO::AIO::poll_cb;
1590 }
1591
1592 IO::AIO::flush;
1593
1594The call to C<poll_cb> inside the loop will normally return instantly, but
1595as soon as more thna C<32> reqeusts are in-flight, it will block until
1596some requests have been handled. This keeps the loop from pushing a large
1597number of C<aio_stat> requests onto the queue.
1598
1599The default value for C<max_outstanding> is very large, so there is no
1600practical limit on the number of outstanding requests.
1370 1601
1371=back 1602=back
1372 1603
1373=head3 STATISTICAL INFORMATION 1604=head3 STATISTICAL INFORMATION
1374 1605
… …
1394Returns the number of requests currently in the pending state (executed, 1625Returns the number of requests currently in the pending state (executed,
1395but not yet processed by poll_cb). 1626but not yet processed by poll_cb).
1396 1627
1397=back 1628=back
1398 1629
1630=head3 MISCELLANEOUS FUNCTIONS
1631
1632IO::AIO implements some functions that might be useful, but are not
1633asynchronous.
1634
1635=over 4
1636
1637=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1638
1639Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1640but is blocking (this makes most sense if you know the input data is
1641likely cached already and the output filehandle is set to non-blocking
1642operations).
1643
1644Returns the number of bytes copied, or C<-1> on error.
1645
1646=item IO::AIO::fadvise $fh, $offset, $len, $advice
1647
1648Simply calls the C<posix_fadvise> function (see its
1649manpage for details). The following advice constants are
1650avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1651C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1652C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1653
1654On systems that do not implement C<posix_fadvise>, this function returns
1655ENOSYS, otherwise the return value of C<posix_fadvise>.
1656
1657=item IO::AIO::madvise $scalar, $offset, $len, $advice
1658
1659Simply calls the C<posix_madvise> function (see its
1660manpage for details). The following advice constants are
1661avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1662C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1663
1664On systems that do not implement C<posix_madvise>, this function returns
1665ENOSYS, otherwise the return value of C<posix_madvise>.
1666
1667=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1668
1669Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1670$scalar (see its manpage for details). The following protect
1671constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1672C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1673
1674On systems that do not implement C<mprotect>, this function returns
1675ENOSYS, otherwise the return value of C<mprotect>.
1676
1677=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1678
1679Memory-maps a file (or anonymous memory range) and attaches it to the
1680given C<$scalar>, which will act like a string scalar.
1681
1682The only operations allowed on the scalar are C<substr>/C<vec> that don't
1683change the string length, and most read-only operations such as copying it
1684or searching it with regexes and so on.
1685
1686Anything else is unsafe and will, at best, result in memory leaks.
1687
1688The memory map associated with the C<$scalar> is automatically removed
1689when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1690C<IO::AIO::munmap> functions are called.
1691
1692This calls the C<mmap>(2) function internally. See your system's manual
1693page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1694
1695The C<$length> must be larger than zero and smaller than the actual
1696filesize.
1697
1698C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1699C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1700
1701C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1702C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1703not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1704(which is set to C<MAP_ANON> if your system only provides this
1705constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1706C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1707C<IO::AIO::MAP_NONBLOCK>
1708
1709If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1710
1711C<$offset> is the offset from the start of the file - it generally must be
1712a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1713
1714Example:
1715
1716 use Digest::MD5;
1717 use IO::AIO;
1718
1719 open my $fh, "<verybigfile"
1720 or die "$!";
1721
1722 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1723 or die "verybigfile: $!";
1724
1725 my $fast_md5 = md5 $data;
1726
1727=item IO::AIO::munmap $scalar
1728
1729Removes a previous mmap and undefines the C<$scalar>.
1730
1731=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1732
1733Calls the C<munlock> function, undoing the effects of a previous
1734C<aio_mlock> call (see its description for details).
1735
1736=item IO::AIO::munlockall
1737
1738Calls the C<munlockall> function.
1739
1740On systems that do not implement C<munlockall>, this function returns
1741ENOSYS, otherwise the return value of C<munlockall>.
1742
1743=back
1744
1399=cut 1745=cut
1400 1746
1401min_parallel 8; 1747min_parallel 8;
1402 1748
1403END { flush } 1749END { flush }
1404 1750
14051; 17511;
1752
1753=head1 EVENT LOOP INTEGRATION
1754
1755It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1756automatically into many event loops:
1757
1758 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1759 use AnyEvent::AIO;
1760
1761You can also integrate IO::AIO manually into many event loops, here are
1762some examples of how to do this:
1763
1764 # EV integration
1765 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1766
1767 # Event integration
1768 Event->io (fd => IO::AIO::poll_fileno,
1769 poll => 'r',
1770 cb => \&IO::AIO::poll_cb);
1771
1772 # Glib/Gtk2 integration
1773 add_watch Glib::IO IO::AIO::poll_fileno,
1774 in => sub { IO::AIO::poll_cb; 1 };
1775
1776 # Tk integration
1777 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1778 readable => \&IO::AIO::poll_cb);
1779
1780 # Danga::Socket integration
1781 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1782 \&IO::AIO::poll_cb);
1406 1783
1407=head2 FORK BEHAVIOUR 1784=head2 FORK BEHAVIOUR
1408 1785
1409This module should do "the right thing" when the process using it forks: 1786This module should do "the right thing" when the process using it forks:
1410 1787

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