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Revision 1.134 by root, Sun Sep 28 03:09:07 2008 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 = '3.07'; 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 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_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);
192
193 push @AIO_REQ, qw(aio_busy); # not exported
213 194
214 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
215 196
216 require XSLoader; 197 require XSLoader;
217 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
218} 199}
219 200
220=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, $length = undef
274 IO::AIO::munlockall
221 275
222=head2 AIO REQUEST FUNCTIONS 276=head2 AIO REQUEST FUNCTIONS
223 277
224All the C<aio_*> calls are more or less thin wrappers around the syscall 278All the C<aio_*> calls are more or less thin wrappers around the syscall
225with the same name (sans C<aio_>). The arguments are similar or identical, 279with the same name (sans C<aio_>). The arguments are similar or identical,
226and they all accept an additional (and optional) C<$callback> argument 280and they all accept an additional (and optional) C<$callback> argument
227which must be a code reference. This code reference will get called with 281which must be a code reference. This code reference will get called with
228the syscall return code (e.g. most syscalls return C<-1> on error, unlike 282the syscall return code (e.g. most syscalls return C<-1> on error, unlike
229perl, which usually delivers "false") as it's sole argument when the given 283perl, which usually delivers "false") as its sole argument after the given
230syscall has been executed asynchronously. 284syscall has been executed asynchronously.
231 285
232All functions expecting a filehandle keep a copy of the filehandle 286All functions expecting a filehandle keep a copy of the filehandle
233internally until the request has finished. 287internally until the request has finished.
234 288
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248your pathnames to the locale (or other) encoding in effect in the user 302your pathnames to the locale (or other) encoding in effect in the user
249environment, d) use Glib::filename_from_unicode on unicode filenames or e) 303environment, d) use Glib::filename_from_unicode on unicode filenames or e)
250use something else to ensure your scalar has the correct contents. 304use something else to ensure your scalar has the correct contents.
251 305
252This works, btw. independent of the internal UTF-8 bit, which IO::AIO 306This works, btw. independent of the internal UTF-8 bit, which IO::AIO
253handles correctly wether it is set or not. 307handles correctly whether it is set or not.
254 308
255=over 4 309=over 4
256 310
257=item $prev_pri = aioreq_pri [$pri] 311=item $prev_pri = aioreq_pri [$pri]
258 312
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305by 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
306change the umask. 360change the umask.
307 361
308Example: 362Example:
309 363
310 aio_open "/etc/passwd", O_RDONLY, 0, sub { 364 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
311 if ($_[0]) { 365 if ($_[0]) {
312 print "open successful, fh is $_[0]\n"; 366 print "open successful, fh is $_[0]\n";
313 ... 367 ...
314 } else { 368 } else {
315 die "open failed: $!\n"; 369 die "open failed: $!\n";
316 } 370 }
317 }; 371 };
318 372
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
319 382
320=item aio_close $fh, $callback->($status) 383=item aio_close $fh, $callback->($status)
321 384
322Asynchronously close a file and call the callback with the result 385Asynchronously close a file and call the callback with the result
323code. 386code.
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336 399
337=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 400=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
338 401
339=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 402=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
340 403
341Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 404Reads or writes C<$length> bytes from or to the specified C<$fh> and
342into the scalar given by C<$data> and offset C<$dataoffset> and calls the 405C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
343callback without the actual number of bytes read (or -1 on error, just 406and calls the callback without the actual number of bytes read (or -1 on
344like the syscall). 407error, just like the syscall).
408
409C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
410offset plus the actual number of bytes read.
345 411
346If C<$offset> is undefined, then the current file descriptor offset will 412If C<$offset> is undefined, then the current file descriptor offset will
347be used (and updated), otherwise the file descriptor offset will not be 413be used (and updated), otherwise the file descriptor offset will not be
348changed by these calls. 414changed by these calls.
349 415
350If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 416If C<$length> is undefined in C<aio_write>, use the remaining length of
417C<$data>.
351 418
352If C<$dataoffset> is less than zero, it will be counted from the end of 419If C<$dataoffset> is less than zero, it will be counted from the end of
353C<$data>. 420C<$data>.
354 421
355The C<$data> scalar I<MUST NOT> be modified in any way while the request 422The C<$data> scalar I<MUST NOT> be modified in any way while the request
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371reading at byte offset C<$in_offset>, and starts writing at the current 438reading at byte offset C<$in_offset>, and starts writing at the current
372file offset of C<$out_fh>. Because of that, it is not safe to issue more 439file offset of C<$out_fh>. Because of that, it is not safe to issue more
373than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 440than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
374other. 441other.
375 442
443Please note that C<aio_sendfile> can read more bytes from C<$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
376This 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
377zero-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
378socket, and C<$in_fh> should refer to mmap'able file. 461socket, and C<$in_fh> should refer to an mmap'able file.
379 462
380If 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>,
381emulated, 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
382regardless of the limitations of the operating system. 466filehandle regardless of the limitations of the operating system.
383
384Please note, however, that C<aio_sendfile> can read more bytes from
385C<$in_fh> than are written, and there is no way to find out how many
386bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
387provides the number of bytes written to C<$out_fh>. Only if the result
388value equals C<$length> one can assume that C<$length> bytes have been
389read.
390 467
391 468
392=item aio_readahead $fh,$offset,$length, $callback->($retval) 469=item aio_readahead $fh,$offset,$length, $callback->($retval)
393 470
394C<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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417 494
418Currently, 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
419error 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
420unless perl itself is compiled with large file support. 497unless perl itself is compiled with large file support.
421 498
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
422Example: Print the length of F</etc/passwd>: 508Example: Print the length of F</etc/passwd>:
423 509
424 aio_stat "/etc/passwd", sub { 510 aio_stat "/etc/passwd", sub {
425 $_[0] and die "stat failed: $!"; 511 $_[0] and die "stat failed: $!";
426 print "size is ", -s _, "\n"; 512 print "size is ", -s _, "\n";
427 }; 513 };
428 514
429 515
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
430=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 561=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
431 562
432Works 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
433and $mtime being undef). Fractional times are supported if the underlying 564and $mtime being undef). Fractional times are supported if the underlying
434syscalls support them. 565syscalls support them.
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482 613
483The only (POSIX-) portable way of calling this function is: 614The only (POSIX-) portable way of calling this function is:
484 615
485 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 616 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
486 617
618See C<aio_stat> for info about some potentially helpful extra constants
619and functions.
487 620
488=item aio_link $srcpath, $dstpath, $callback->($status) 621=item aio_link $srcpath, $dstpath, $callback->($status)
489 622
490Asynchronously 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
491the path C<$dstpath> and call the callback with the result code. 624the path C<$dstpath> and call the callback with the result code.
… …
527 660
528Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 661Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
529directory (i.e. opendir + readdir + closedir). The entries will not be 662directory (i.e. opendir + readdir + closedir). The entries will not be
530sorted, and will B<NOT> include the C<.> and C<..> entries. 663sorted, and will B<NOT> include the C<.> and C<..> entries.
531 664
532The callback a single argument which is either C<undef> or an array-ref 665The callback is passed a single argument which is either C<undef> or an
533with the filenames. 666array-ref with the filenames.
667
668
669=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
670
671Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
672behaviour and output format. In case of an error, C<$entries> will be
673C<undef>.
674
675The flags are a combination of the following constants, ORed together (the
676flags will also be passed to the callback, possibly modified):
677
678=over 4
679
680=item IO::AIO::READDIR_DENTS
681
682When this flag is off, then the callback gets an arrayref consisting of
683names only (as with C<aio_readdir>), otherwise it gets an arrayref with
684C<[$name, $type, $inode]> arrayrefs, each describing a single directory
685entry in more detail.
686
687C<$name> is the name of the entry.
688
689C<$type> is one of the C<IO::AIO::DT_xxx> constants:
690
691C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
692C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
693C<IO::AIO::DT_WHT>.
694
695C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
696know, you have to run stat yourself. Also, for speed reasons, the C<$type>
697scalars are read-only: you can not modify them.
698
699C<$inode> is the inode number (which might not be exact on systems with 64
700bit inode numbers and 32 bit perls). This field has unspecified content on
701systems that do not deliver the inode information.
702
703=item IO::AIO::READDIR_DIRS_FIRST
704
705When this flag is set, then the names will be returned in an order where
706likely directories come first, in optimal stat order. This is useful when
707you need to quickly find directories, or you want to find all directories
708while avoiding to stat() each entry.
709
710If the system returns type information in readdir, then this is used
711to find directories directly. Otherwise, likely directories are names
712beginning with ".", or otherwise names with no dots, of which names with
713short names are tried first.
714
715=item IO::AIO::READDIR_STAT_ORDER
716
717When this flag is set, then the names will be returned in an order
718suitable for stat()'ing each one. That is, when you plan to stat()
719all files in the given directory, then the returned order will likely
720be fastest.
721
722If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
723the likely dirs come first, resulting in a less optimal stat order.
724
725=item IO::AIO::READDIR_FOUND_UNKNOWN
726
727This flag should not be set when calling C<aio_readdirx>. Instead, it
728is being set by C<aio_readdirx>, when any of the C<$type>'s found were
729C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
730C<$type>'s are known, which can be used to speed up some algorithms.
731
732=back
534 733
535 734
536=item aio_load $path, $data, $callback->($status) 735=item aio_load $path, $data, $callback->($status)
537 736
538This is a composite request that tries to fully load the given file into 737This is a composite request that tries to fully load the given file into
… …
563 762
564=item aio_copy $srcpath, $dstpath, $callback->($status) 763=item aio_copy $srcpath, $dstpath, $callback->($status)
565 764
566Try 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
567destination) from C<$srcpath> to C<$dstpath> and call the callback with 766destination) from C<$srcpath> to C<$dstpath> and call the callback with
568the C<0> (error) or C<-1> ok. 767a status of C<0> (ok) or C<-1> (error, see C<$!>).
569 768
570This is a composite request that creates the destination file with 769This is a composite request that creates the destination file with
571mode 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
572C<aio_sendfile>, followed by restoring atime, mtime, access mode and 771C<aio_sendfile>, followed by restoring atime, mtime, access mode and
573uid/gid, in that order. 772uid/gid, in that order.
… …
585 my $grp = aio_group $cb; 784 my $grp = aio_group $cb;
586 785
587 aioreq_pri $pri; 786 aioreq_pri $pri;
588 add $grp aio_open $src, O_RDONLY, 0, sub { 787 add $grp aio_open $src, O_RDONLY, 0, sub {
589 if (my $src_fh = $_[0]) { 788 if (my $src_fh = $_[0]) {
590 my @stat = stat $src_fh; 789 my @stat = stat $src_fh; # hmm, might block over nfs?
591 790
592 aioreq_pri $pri; 791 aioreq_pri $pri;
593 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 {
594 if (my $dst_fh = $_[0]) { 793 if (my $dst_fh = $_[0]) {
595 aioreq_pri $pri; 794 aioreq_pri $pri;
596 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 795 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
597 if ($_[0] == $stat[7]) { 796 if ($_[0] == $stat[7]) {
598 $grp->result (0); 797 $grp->result (0);
599 close $src_fh; 798 close $src_fh;
600 799
601 # those should not normally block. should. should. 800 my $ch = sub {
602 utime $stat[8], $stat[9], $dst; 801 aioreq_pri $pri;
603 chmod $stat[2] & 07777, $dst_fh; 802 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
604 chown $stat[4], $stat[5], $dst_fh; 803 aioreq_pri $pri;
804 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
805 aioreq_pri $pri;
806 add $grp aio_close $dst_fh;
807 }
808 };
809 };
605 810
606 aioreq_pri $pri; 811 aioreq_pri $pri;
607 add $grp aio_close $dst_fh; 812 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
813 if ($_[0] < 0 && $! == ENOSYS) {
814 aioreq_pri $pri;
815 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
816 } else {
817 $ch->();
818 }
819 };
608 } else { 820 } else {
609 $grp->result (-1); 821 $grp->result (-1);
610 close $src_fh; 822 close $src_fh;
611 close $dst_fh; 823 close $dst_fh;
612 824
… …
629 841
630=item aio_move $srcpath, $dstpath, $callback->($status) 842=item aio_move $srcpath, $dstpath, $callback->($status)
631 843
632Try 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
633destination) from C<$srcpath> to C<$dstpath> and call the callback with 845destination) from C<$srcpath> to C<$dstpath> and call the callback with
634the C<0> (error) or C<-1> ok. 846a status of C<0> (ok) or C<-1> (error, see C<$!>).
635 847
636This is a composite request that tries to rename(2) the file first. If 848This is a composite request that tries to rename(2) the file first; if
637rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 849rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
638that is successful, unlinking the C<$srcpath>. 850that is successful, unlinks the C<$srcpath>.
639 851
640=cut 852=cut
641 853
642sub aio_move($$;$) { 854sub aio_move($$;$) {
643 my ($src, $dst, $cb) = @_; 855 my ($src, $dst, $cb) = @_;
… …
690 902
691Implementation notes. 903Implementation notes.
692 904
693The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 905The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
694 906
907If readdir returns file type information, then this is used directly to
908find directories.
909
695After reading the directory, the modification time, size etc. of the 910Otherwise, after reading the directory, the modification time, size etc.
696directory before and after the readdir is checked, and if they match (and 911of the directory before and after the readdir is checked, and if they
697isn't the current time), the link count will be used to decide how many 912match (and isn't the current time), the link count will be used to decide
698entries are directories (if >= 2). Otherwise, no knowledge of the number 913how many entries are directories (if >= 2). Otherwise, no knowledge of the
699of subdirectories will be assumed. 914number of subdirectories will be assumed.
700 915
701Then entries will be sorted into likely directories (everything without 916Then entries will be sorted into likely directories a non-initial dot
702a non-initial dot currently) and likely non-directories (everything 917currently) and likely non-directories (see C<aio_readdirx>). Then every
703else). Then every entry plus an appended C</.> will be C<stat>'ed, 918entry plus an appended C</.> will be C<stat>'ed, likely directories first,
704likely directories first. If that succeeds, it assumes that the entry 919in order of their inode numbers. If that succeeds, it assumes that the
705is a directory or a symlink to directory (which will be checked 920entry is a directory or a symlink to directory (which will be checked
706seperately). This is often faster than stat'ing the entry itself because 921seperately). This is often faster than stat'ing the entry itself because
707filesystems might detect the type of the entry without reading the inode 922filesystems might detect the type of the entry without reading the inode
708data (e.g. ext2fs filetype feature). 923data (e.g. ext2fs filetype feature), even on systems that cannot return
924the filetype information on readdir.
709 925
710If the known number of directories (link count - 2) has been reached, the 926If the known number of directories (link count - 2) has been reached, the
711rest of the entries is assumed to be non-directories. 927rest of the entries is assumed to be non-directories.
712 928
713This only works with certainty on POSIX (= UNIX) filesystems, which 929This only works with certainty on POSIX (= UNIX) filesystems, which
… …
735 my $now = time; 951 my $now = time;
736 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 952 my $hash1 = join ":", (stat _)[0,1,3,7,9];
737 953
738 # read the directory entries 954 # read the directory entries
739 aioreq_pri $pri; 955 aioreq_pri $pri;
740 add $grp aio_readdir $path, sub { 956 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
741 my $entries = shift 957 my $entries = shift
742 or return $grp->result (); 958 or return $grp->result ();
743 959
744 # stat the dir another time 960 # stat the dir another time
745 aioreq_pri $pri; 961 aioreq_pri $pri;
… …
751 # take the slow route if anything looks fishy 967 # take the slow route if anything looks fishy
752 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 968 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
753 $ndirs = -1; 969 $ndirs = -1;
754 } else { 970 } else {
755 # if nlink == 2, we are finished 971 # if nlink == 2, we are finished
756 # on non-posix-fs's, we rely on nlink < 2 972 # for non-posix-fs's, we rely on nlink < 2
757 $ndirs = (stat _)[3] - 2 973 $ndirs = (stat _)[3] - 2
758 or return $grp->result ([], $entries); 974 or return $grp->result ([], $entries);
759 } 975 }
760 976
761 # sort into likely dirs and likely nondirs
762 # dirs == files without ".", short entries first
763 $entries = [map $_->[0],
764 sort { $b->[1] cmp $a->[1] }
765 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
766 @$entries];
767
768 my (@dirs, @nondirs); 977 my (@dirs, @nondirs);
769 978
770 my $statgrp = add $grp aio_group sub { 979 my $statgrp = add $grp aio_group sub {
771 $grp->result (\@dirs, \@nondirs); 980 $grp->result (\@dirs, \@nondirs);
772 }; 981 };
773 982
774 limit $statgrp $maxreq; 983 limit $statgrp $maxreq;
775 feed $statgrp sub { 984 feed $statgrp sub {
776 return unless @$entries; 985 return unless @$entries;
777 my $entry = pop @$entries; 986 my $entry = shift @$entries;
778 987
779 aioreq_pri $pri; 988 aioreq_pri $pri;
780 add $statgrp aio_stat "$path/$entry/.", sub { 989 add $statgrp aio_stat "$path/$entry/.", sub {
781 if ($_[0] < 0) { 990 if ($_[0] < 0) {
782 push @nondirs, $entry; 991 push @nondirs, $entry;
… …
855callback with the fdatasync result code. 1064callback with the fdatasync result code.
856 1065
857If this call isn't available because your OS lacks it or it couldn't be 1066If this call isn't available because your OS lacks it or it couldn't be
858detected, it will be emulated by calling C<fsync> instead. 1067detected, it will be emulated by calling C<fsync> instead.
859 1068
1069=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1070
1071Sync the data portion of the file specified by C<$offset> and C<$length>
1072to disk (but NOT the metadata), by calling the Linux-specific
1073sync_file_range call. If sync_file_range is not available or it returns
1074ENOSYS, then fdatasync or fsync is being substituted.
1075
1076C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1077C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1078C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1079manpage for details.
1080
860=item aio_pathsync $path, $callback->($status) 1081=item aio_pathsync $path, $callback->($status)
861 1082
862This request tries to open, fsync and close the given path. This is a 1083This request tries to open, fsync and close the given path. This is a
863composite request intended tosync directories after directory operations 1084composite request intended to sync directories after directory operations
864(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
865specific effect, but usually it makes sure that directory changes get 1086specific effect, but usually it makes sure that directory changes get
866written 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,
867not just directories. 1088not just directories.
1089
1090Future versions of this function might fall back to other methods when
1091C<fsync> on the directory fails (such as calling C<sync>).
868 1092
869Passes C<0> when everything went ok, and C<-1> on error. 1093Passes C<0> when everything went ok, and C<-1> on error.
870 1094
871=cut 1095=cut
872 1096
… …
893 }; 1117 };
894 1118
895 $grp 1119 $grp
896} 1120}
897 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
898=item aio_group $callback->(...) 1188=item aio_group $callback->(...)
899 1189
900This 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
901container 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
902many requests into a single, composite, request with a definite callback 1192many requests into a single, composite, request with a definite callback
… …
951=item cancel $req 1241=item cancel $req
952 1242
953Cancels the request, if possible. Has the effect of skipping execution 1243Cancels the request, if possible. Has the effect of skipping execution
954when entering the B<execute> state and skipping calling the callback when 1244when entering the B<execute> state and skipping calling the callback when
955entering the the B<result> state, but will leave the request otherwise 1245entering the the B<result> state, but will leave the request otherwise
956untouched. That means that requests that currently execute will not be 1246untouched (with the exception of readdir). That means that requests that
957stopped and resources held by the request will not be freed prematurely. 1247currently execute will not be stopped and resources held by the request
1248will not be freed prematurely.
958 1249
959=item cb $req $callback->(...) 1250=item cb $req $callback->(...)
960 1251
961Replace (or simply set) the callback registered to the request. 1252Replace (or simply set) the callback registered to the request.
962 1253
… …
1036=item $grp->cancel_subs 1327=item $grp->cancel_subs
1037 1328
1038Cancel all subrequests and clears any feeder, but not the group request 1329Cancel all subrequests and clears any feeder, but not the group request
1039itself. 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.
1040 1331
1332The group request will finish normally (you cannot add requests to the
1333group).
1334
1041=item $grp->result (...) 1335=item $grp->result (...)
1042 1336
1043Set 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
1044subrequests have finished and set the groups errno to the current value 1338subrequests have finished and set the groups errno to the current value
1045of 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,
… …
1060=item feed $grp $callback->($grp) 1354=item feed $grp $callback->($grp)
1061 1355
1062Sets a feeder/generator on this group: every group can have an attached 1356Sets a feeder/generator on this group: every group can have an attached
1063generator that generates requests if idle. The idea behind this is that, 1357generator that generates requests if idle. The idea behind this is that,
1064although you could just queue as many requests as you want in a group, 1358although you could just queue as many requests as you want in a group,
1065this might starve other requests for a potentially long time. For 1359this might starve other requests for a potentially long time. For example,
1066example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1360C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1067requests, delaying any later requests for a long time. 1361delaying any later requests for a long time.
1068 1362
1069To avoid this, and allow incremental generation of requests, you can 1363To avoid this, and allow incremental generation of requests, you can
1070instead a group and set a feeder on it that generates those requests. The 1364instead a group and set a feeder on it that generates those requests. The
1071feed callback will be called whenever there are few enough (see C<limit>, 1365feed callback will be called whenever there are few enough (see C<limit>,
1072below) requests active in the group itself and is expected to queue more 1366below) requests active in the group itself and is expected to queue more
… …
1076not impose any limits). 1370not impose any limits).
1077 1371
1078If the feed does not queue more requests when called, it will be 1372If the feed does not queue more requests when called, it will be
1079automatically removed from the group. 1373automatically removed from the group.
1080 1374
1081If the feed limit is C<0>, it will be set to C<2> automatically. 1375If the feed limit is C<0> when this method is called, it will be set to
1376C<2> automatically.
1082 1377
1083Example: 1378Example:
1084 1379
1085 # stat all files in @files, but only ever use four aio requests concurrently: 1380 # stat all files in @files, but only ever use four aio requests concurrently:
1086 1381
… …
1098Sets the feeder limit for the group: The feeder will be called whenever 1393Sets the feeder limit for the group: The feeder will be called whenever
1099the group contains less than this many requests. 1394the group contains less than this many requests.
1100 1395
1101Setting the limit to C<0> will pause the feeding process. 1396Setting the limit to C<0> will pause the feeding process.
1102 1397
1398The default value for the limit is C<0>, but note that setting a feeder
1399automatically bumps it up to C<2>.
1400
1103=back 1401=back
1104 1402
1105=head2 SUPPORT FUNCTIONS 1403=head2 SUPPORT FUNCTIONS
1106 1404
1107=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1405=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1109=over 4 1407=over 4
1110 1408
1111=item $fileno = IO::AIO::poll_fileno 1409=item $fileno = IO::AIO::poll_fileno
1112 1410
1113Return the I<request result pipe file descriptor>. This filehandle must be 1411Return the I<request result pipe file descriptor>. This filehandle must be
1114polled 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,
1115select, 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
1116to call C<poll_cb> to check the results. 1414you have to call C<poll_cb> to check the results.
1117 1415
1118See C<poll_cb> for an example. 1416See C<poll_cb> for an example.
1119 1417
1120=item IO::AIO::poll_cb 1418=item IO::AIO::poll_cb
1121 1419
1122Process some outstanding events on the result pipe. You have to call this 1420Process some outstanding events on the result pipe. You have to call
1123regularly. 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
1124returned earlier for whatever reason. Returns immediately when no events 1422were no events to process), or C<-1> if it returned earlier for whatever
1125are outstanding. The amount of events processed depends on the settings of 1423reason. Returns immediately when no events are outstanding. The amount of
1126C<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>.
1127 1426
1128If not all requests were processed for whatever reason, the filehandle 1427If not all requests were processed for whatever reason, the filehandle
1129will 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
1130do anything special to have it called later. 1429do anything special to have it called later.
1131 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
1132Example: Install an Event watcher that automatically calls 1438Example: Install an Event watcher that automatically calls
1133IO::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):
1134 1441
1135 Event->io (fd => IO::AIO::poll_fileno, 1442 Event->io (fd => IO::AIO::poll_fileno,
1136 poll => 'r', async => 1, 1443 poll => 'r', async => 1,
1137 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;
1138 1472
1139=item IO::AIO::max_poll_reqs $nreqs 1473=item IO::AIO::max_poll_reqs $nreqs
1140 1474
1141=item IO::AIO::max_poll_time $seconds 1475=item IO::AIO::max_poll_time $seconds
1142 1476
… …
1167 # use a low priority so other tasks have priority 1501 # use a low priority so other tasks have priority
1168 Event->io (fd => IO::AIO::poll_fileno, 1502 Event->io (fd => IO::AIO::poll_fileno,
1169 poll => 'r', nice => 1, 1503 poll => 'r', nice => 1,
1170 cb => &IO::AIO::poll_cb); 1504 cb => &IO::AIO::poll_cb);
1171 1505
1172=item IO::AIO::poll_wait
1173
1174If there are any outstanding requests and none of them in the result
1175phase, wait till the result filehandle becomes ready for reading (simply
1176does a C<select> on the filehandle. This is useful if you want to
1177synchronously wait for some requests to finish).
1178
1179See C<nreqs> for an example.
1180
1181=item IO::AIO::poll
1182
1183Waits until some requests have been handled.
1184
1185Returns the number of requests processed, but is otherwise strictly
1186equivalent to:
1187
1188 IO::AIO::poll_wait, IO::AIO::poll_cb
1189
1190=item IO::AIO::flush
1191
1192Wait till all outstanding AIO requests have been handled.
1193
1194Strictly equivalent to:
1195
1196 IO::AIO::poll_wait, IO::AIO::poll_cb
1197 while IO::AIO::nreqs;
1198
1199=back 1506=back
1200 1507
1201=head3 CONTROLLING THE NUMBER OF THREADS 1508=head3 CONTROLLING THE NUMBER OF THREADS
1202 1509
1203=over 1510=over
… …
1236 1543
1237Under normal circumstances you don't need to call this function. 1544Under normal circumstances you don't need to call this function.
1238 1545
1239=item IO::AIO::max_idle $nthreads 1546=item IO::AIO::max_idle $nthreads
1240 1547
1241Limit the number of threads (default: 4) that are allowed to idle (i.e., 1548Limit the number of threads (default: 4) that are allowed to idle
1242threads that did not get a request to process within 10 seconds). That 1549(i.e., threads that did not get a request to process within the idle
1243means if a thread becomes idle while C<$nthreads> other threads are also 1550timeout (default: 10 seconds). That means if a thread becomes idle while
1244idle, it will free its resources and exit. 1551C<$nthreads> other threads are also idle, it will free its resources and
1552exit.
1245 1553
1246This 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)
1247to allow for extremely high load situations, but want to free resources 1555to allow for extremely high load situations, but want to free resources
1248under normal circumstances (1000 threads can easily consume 30MB of RAM). 1556under normal circumstances (1000 threads can easily consume 30MB of RAM).
1249 1557
1250The default is probably ok in most situations, especially if thread 1558The default is probably ok in most situations, especially if thread
1251creation 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
1252want to use larger values. 1560want to use larger values.
1253 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
1254=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.
1255 1577
1256This 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
1257blocks, 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
1258use an C<aio_group> together with a feed callback. 1580use an C<aio_group> together with a feed callback.
1259 1581
1260Sets 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
1261do queue up more than this number of requests, the next call to the 1583a lot of files, you can write somehting like this:
1262C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1263function will block until the limit is no longer exceeded.
1264 1584
1265The default value is very large, so there is no practical limit on the 1585 IO::AIO::max_outstanding 32;
1266number of outstanding requests.
1267 1586
1268You can still queue as many requests as you want. Therefore, 1587 for my $path (...) {
1269C<max_outstanding> is mainly useful in simple scripts (with low values) or 1588 aio_stat $path , ...;
1270as 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.
1271 1601
1272=back 1602=back
1273 1603
1274=head3 STATISTICAL INFORMATION 1604=head3 STATISTICAL INFORMATION
1275 1605
… …
1295Returns the number of requests currently in the pending state (executed, 1625Returns the number of requests currently in the pending state (executed,
1296but not yet processed by poll_cb). 1626but not yet processed by poll_cb).
1297 1627
1298=back 1628=back
1299 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
1300=cut 1745=cut
1301 1746
1302min_parallel 8; 1747min_parallel 8;
1303 1748
1304END { flush } 1749END { flush }
1305 1750
13061; 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);
1307 1783
1308=head2 FORK BEHAVIOUR 1784=head2 FORK BEHAVIOUR
1309 1785
1310This 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:
1311 1787

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