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Revision 1.125 by root, Sat May 10 22:47:34 2008 UTC vs.
Revision 1.201 by root, Tue Jul 5 09:24:11 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 = '3.0'; 173 our $VERSION = '3.93';
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_realpath 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_realpath $path, $callback->($link)
228 aio_rename $srcpath, $dstpath, $callback->($status)
229 aio_mkdir $pathname, $mode, $callback->($status)
230 aio_rmdir $pathname, $callback->($status)
231 aio_readdir $pathname, $callback->($entries)
232 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
233 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
234 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
235 aio_load $path, $data, $callback->($status)
236 aio_copy $srcpath, $dstpath, $callback->($status)
237 aio_move $srcpath, $dstpath, $callback->($status)
238 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
239 aio_rmtree $path, $callback->($status)
240 aio_sync $callback->($status)
241 aio_fsync $fh, $callback->($status)
242 aio_fdatasync $fh, $callback->($status)
243 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
244 aio_pathsync $path, $callback->($status)
245 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
247 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
248 aio_mlockall $flags, $callback->($status)
249 aio_group $callback->(...)
250 aio_nop $callback->()
251
252 $prev_pri = aioreq_pri [$pri]
253 aioreq_nice $pri_adjust
254
255 IO::AIO::poll_wait
256 IO::AIO::poll_cb
257 IO::AIO::poll
258 IO::AIO::flush
259 IO::AIO::max_poll_reqs $nreqs
260 IO::AIO::max_poll_time $seconds
261 IO::AIO::min_parallel $nthreads
262 IO::AIO::max_parallel $nthreads
263 IO::AIO::max_idle $nthreads
264 IO::AIO::idle_timeout $seconds
265 IO::AIO::max_outstanding $maxreqs
266 IO::AIO::nreqs
267 IO::AIO::nready
268 IO::AIO::npending
269
270 IO::AIO::sendfile $ofh, $ifh, $offset, $count
271 IO::AIO::fadvise $fh, $offset, $len, $advice
272 IO::AIO::madvise $scalar, $offset, $length, $advice
273 IO::AIO::mprotect $scalar, $offset, $length, $protect
274 IO::AIO::munlock $scalar, $offset = 0, $length = undef
275 IO::AIO::munlockall
221 276
222=head2 AIO REQUEST FUNCTIONS 277=head2 AIO REQUEST FUNCTIONS
223 278
224All the C<aio_*> calls are more or less thin wrappers around the syscall 279All the C<aio_*> calls are more or less thin wrappers around the syscall
225with the same name (sans C<aio_>). The arguments are similar or identical, 280with the same name (sans C<aio_>). The arguments are similar or identical,
226and they all accept an additional (and optional) C<$callback> argument 281and they all accept an additional (and optional) C<$callback> argument
227which must be a code reference. This code reference will get called with 282which 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 283the 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 284perl, which usually delivers "false") as its sole argument after the given
230syscall has been executed asynchronously. 285syscall has been executed asynchronously.
231 286
232All functions expecting a filehandle keep a copy of the filehandle 287All functions expecting a filehandle keep a copy of the filehandle
233internally until the request has finished. 288internally until the request has finished.
234 289
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248your pathnames to the locale (or other) encoding in effect in the user 303your pathnames to the locale (or other) encoding in effect in the user
249environment, d) use Glib::filename_from_unicode on unicode filenames or e) 304environment, d) use Glib::filename_from_unicode on unicode filenames or e)
250use something else to ensure your scalar has the correct contents. 305use something else to ensure your scalar has the correct contents.
251 306
252This works, btw. independent of the internal UTF-8 bit, which IO::AIO 307This works, btw. independent of the internal UTF-8 bit, which IO::AIO
253handles correctly wether it is set or not. 308handles correctly whether it is set or not.
254 309
255=over 4 310=over 4
256 311
257=item $prev_pri = aioreq_pri [$pri] 312=item $prev_pri = aioreq_pri [$pri]
258 313
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305by the umask in effect then the request is being executed, so better never 360by the umask in effect then the request is being executed, so better never
306change the umask. 361change the umask.
307 362
308Example: 363Example:
309 364
310 aio_open "/etc/passwd", O_RDONLY, 0, sub { 365 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
311 if ($_[0]) { 366 if ($_[0]) {
312 print "open successful, fh is $_[0]\n"; 367 print "open successful, fh is $_[0]\n";
313 ... 368 ...
314 } else { 369 } else {
315 die "open failed: $!\n"; 370 die "open failed: $!\n";
316 } 371 }
317 }; 372 };
318 373
374In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
375C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
376following POSIX and non-POSIX constants are available (missing ones on
377your system are, as usual, C<0>):
378
379C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
380C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
381C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
382
319 383
320=item aio_close $fh, $callback->($status) 384=item aio_close $fh, $callback->($status)
321 385
322Asynchronously close a file and call the callback with the result 386Asynchronously close a file and call the callback with the result
323code. 387code.
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336 400
337=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 401=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
338 402
339=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 403=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
340 404
341Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 405Reads or writes C<$length> bytes from or to the specified C<$fh> and
342into the scalar given by C<$data> and offset C<$dataoffset> and calls the 406C<$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 407and calls the callback without the actual number of bytes read (or -1 on
344like the syscall). 408error, just like the syscall).
409
410C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
411offset plus the actual number of bytes read.
345 412
346If C<$offset> is undefined, then the current file descriptor offset will 413If C<$offset> is undefined, then the current file descriptor offset will
347be used (and updated), otherwise the file descriptor offset will not be 414be used (and updated), otherwise the file descriptor offset will not be
348changed by these calls. 415changed by these calls.
349 416
350If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 417If C<$length> is undefined in C<aio_write>, use the remaining length of
418C<$data>.
351 419
352If C<$dataoffset> is less than zero, it will be counted from the end of 420If C<$dataoffset> is less than zero, it will be counted from the end of
353C<$data>. 421C<$data>.
354 422
355The C<$data> scalar I<MUST NOT> be modified in any way while the request 423The C<$data> scalar I<MUST NOT> be modified in any way while the request
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369 437
370Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 438Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
371reading at byte offset C<$in_offset>, and starts writing at the current 439reading 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 440file 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 441than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
374other. 442other. The same C<$in_fh> works fine though, as this function does not
443move or use the file offset of C<$in_fh>.
375 444
445Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
446are written, and there is no way to find out how many more bytes have been
447read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
448number of bytes written to C<$out_fh>. Only if the result value equals
449C<$length> one can assume that C<$length> bytes have been read.
450
451Unlike with other C<aio_> functions, it makes a lot of sense to use
452C<aio_sendfile> on non-blocking sockets, as long as one end (typically
453the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
454the socket I/O will be non-blocking. Note, however, that you can run
455into a trap where C<aio_sendfile> reads some data with readahead, then
456fails to write all data, and when the socket is ready the next time, the
457data in the cache is already lost, forcing C<aio_sendfile> to again hit
458the disk. Explicit C<aio_read> + C<aio_write> let's you better control
459resource usage.
460
376This call tries to make use of a native C<sendfile> syscall to provide 461This call tries to make use of a native C<sendfile>-like syscall to
377zero-copy operation. For this to work, C<$out_fh> should refer to a 462provide zero-copy operation. For this to work, C<$out_fh> should refer to
378socket, and C<$in_fh> should refer to mmap'able file. 463a socket, and C<$in_fh> should refer to an mmap'able file.
379 464
380If the native sendfile call fails or is not implemented, it will be 465If a native sendfile cannot be found or it fails with C<ENOSYS>,
381emulated, so you can call C<aio_sendfile> on any type of filehandle 466C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
467C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
382regardless of the limitations of the operating system. 468type of filehandle regardless of the limitations of the operating system.
383 469
384Please note, however, that C<aio_sendfile> can read more bytes from 470As native sendfile syscalls (as practically any non-POSIX interface hacked
385C<$in_fh> than are written, and there is no way to find out how many 471together in a hurry to improve benchmark numbers) tend to be rather buggy
386bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 472on many systems, this implementation tries to work around some known bugs
387provides the number of bytes written to C<$out_fh>. Only if the result 473in Linux and FreeBSD kernels (probably others, too), but that might fail,
388value equals C<$length> one can assume that C<$length> bytes have been 474so you really really should check the return value of C<aio_sendfile> -
389read. 475fewre bytes than expected might have been transferred.
390 476
391 477
392=item aio_readahead $fh,$offset,$length, $callback->($retval) 478=item aio_readahead $fh,$offset,$length, $callback->($retval)
393 479
394C<aio_readahead> populates the page cache with data from a file so that 480C<aio_readahead> populates the page cache with data from a file so that
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417 503
418Currently, the stats are always 64-bit-stats, i.e. instead of returning an 504Currently, 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 505error when stat'ing a large file, the results will be silently truncated
420unless perl itself is compiled with large file support. 506unless perl itself is compiled with large file support.
421 507
508To help interpret the mode and dev/rdev stat values, IO::AIO offers the
509following constants and functions (if not implemented, the constants will
510be C<0> and the functions will either C<croak> or fall back on traditional
511behaviour).
512
513C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
514C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
515C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
516
422Example: Print the length of F</etc/passwd>: 517Example: Print the length of F</etc/passwd>:
423 518
424 aio_stat "/etc/passwd", sub { 519 aio_stat "/etc/passwd", sub {
425 $_[0] and die "stat failed: $!"; 520 $_[0] and die "stat failed: $!";
426 print "size is ", -s _, "\n"; 521 print "size is ", -s _, "\n";
427 }; 522 };
428 523
429 524
525=item aio_statvfs $fh_or_path, $callback->($statvfs)
526
527Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
528whether a file handle or path was passed.
529
530On success, the callback is passed a hash reference with the following
531members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
532C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
533is passed.
534
535The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
536C<ST_NOSUID>.
537
538The following non-POSIX IO::AIO::ST_* flag masks are defined to
539their correct value when available, or to C<0> on systems that do
540not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
541C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
542C<ST_NODIRATIME> and C<ST_RELATIME>.
543
544Example: stat C</wd> and dump out the data if successful.
545
546 aio_statvfs "/wd", sub {
547 my $f = $_[0]
548 or die "statvfs: $!";
549
550 use Data::Dumper;
551 say Dumper $f;
552 };
553
554 # result:
555 {
556 bsize => 1024,
557 bfree => 4333064312,
558 blocks => 10253828096,
559 files => 2050765568,
560 flag => 4096,
561 favail => 2042092649,
562 bavail => 4333064312,
563 ffree => 2042092649,
564 namemax => 255,
565 frsize => 1024,
566 fsid => 1810
567 }
568
569
430=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 570=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
431 571
432Works like perl's C<utime> function (including the special case of $atime 572Works like perl's C<utime> function (including the special case of $atime
433and $mtime being undef). Fractional times are supported if the underlying 573and $mtime being undef). Fractional times are supported if the underlying
434syscalls support them. 574syscalls support them.
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482 622
483The only (POSIX-) portable way of calling this function is: 623The only (POSIX-) portable way of calling this function is:
484 624
485 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 625 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
486 626
627See C<aio_stat> for info about some potentially helpful extra constants
628and functions.
487 629
488=item aio_link $srcpath, $dstpath, $callback->($status) 630=item aio_link $srcpath, $dstpath, $callback->($status)
489 631
490Asynchronously create a new link to the existing object at C<$srcpath> at 632Asynchronously create a new link to the existing object at C<$srcpath> at
491the path C<$dstpath> and call the callback with the result code. 633the path C<$dstpath> and call the callback with the result code.
… …
502Asynchronously read the symlink specified by C<$path> and pass it to 644Asynchronously read the symlink specified by C<$path> and pass it to
503the callback. If an error occurs, nothing or undef gets passed to the 645the callback. If an error occurs, nothing or undef gets passed to the
504callback. 646callback.
505 647
506 648
649=item aio_realpath $path, $callback->($path)
650
651Asynchronously make the path absolute and resolve any symlinks in
652C<$path>. The resulting path only consists of directories.
653
654This request can be used to get the absolute path of the current working
655directory by passing it a path of F<.> (a single dot).
656
657
507=item aio_rename $srcpath, $dstpath, $callback->($status) 658=item aio_rename $srcpath, $dstpath, $callback->($status)
508 659
509Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 660Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
510rename(2) and call the callback with the result code. 661rename(2) and call the callback with the result code.
511 662
… …
527 678
528Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 679Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
529directory (i.e. opendir + readdir + closedir). The entries will not be 680directory (i.e. opendir + readdir + closedir). The entries will not be
530sorted, and will B<NOT> include the C<.> and C<..> entries. 681sorted, and will B<NOT> include the C<.> and C<..> entries.
531 682
532The callback a single argument which is either C<undef> or an array-ref 683The callback is passed a single argument which is either C<undef> or an
533with the filenames. 684array-ref with the filenames.
685
686
687=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
688
689Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
690behaviour and output format. In case of an error, C<$entries> will be
691C<undef>.
692
693The flags are a combination of the following constants, ORed together (the
694flags will also be passed to the callback, possibly modified):
695
696=over 4
697
698=item IO::AIO::READDIR_DENTS
699
700When this flag is off, then the callback gets an arrayref consisting of
701names only (as with C<aio_readdir>), otherwise it gets an arrayref with
702C<[$name, $type, $inode]> arrayrefs, each describing a single directory
703entry in more detail.
704
705C<$name> is the name of the entry.
706
707C<$type> is one of the C<IO::AIO::DT_xxx> constants:
708
709C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
710C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
711C<IO::AIO::DT_WHT>.
712
713C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
714know, you have to run stat yourself. Also, for speed reasons, the C<$type>
715scalars are read-only: you can not modify them.
716
717C<$inode> is the inode number (which might not be exact on systems with 64
718bit inode numbers and 32 bit perls). This field has unspecified content on
719systems that do not deliver the inode information.
720
721=item IO::AIO::READDIR_DIRS_FIRST
722
723When this flag is set, then the names will be returned in an order where
724likely directories come first, in optimal stat order. This is useful when
725you need to quickly find directories, or you want to find all directories
726while avoiding to stat() each entry.
727
728If the system returns type information in readdir, then this is used
729to find directories directly. Otherwise, likely directories are names
730beginning with ".", or otherwise names with no dots, of which names with
731short names are tried first.
732
733=item IO::AIO::READDIR_STAT_ORDER
734
735When this flag is set, then the names will be returned in an order
736suitable for stat()'ing each one. That is, when you plan to stat()
737all files in the given directory, then the returned order will likely
738be fastest.
739
740If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
741the likely dirs come first, resulting in a less optimal stat order.
742
743=item IO::AIO::READDIR_FOUND_UNKNOWN
744
745This flag should not be set when calling C<aio_readdirx>. Instead, it
746is being set by C<aio_readdirx>, when any of the C<$type>'s found were
747C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
748C<$type>'s are known, which can be used to speed up some algorithms.
749
750=back
534 751
535 752
536=item aio_load $path, $data, $callback->($status) 753=item aio_load $path, $data, $callback->($status)
537 754
538This is a composite request that tries to fully load the given file into 755This is a composite request that tries to fully load the given file into
… …
563 780
564=item aio_copy $srcpath, $dstpath, $callback->($status) 781=item aio_copy $srcpath, $dstpath, $callback->($status)
565 782
566Try to copy the I<file> (directories not supported as either source or 783Try to copy the I<file> (directories not supported as either source or
567destination) from C<$srcpath> to C<$dstpath> and call the callback with 784destination) from C<$srcpath> to C<$dstpath> and call the callback with
568the C<0> (error) or C<-1> ok. 785a status of C<0> (ok) or C<-1> (error, see C<$!>).
569 786
570This is a composite request that it creates the destination file with 787This is a composite request that creates the destination file with
571mode 0200 and copies the contents of the source file into it using 788mode 0200 and copies the contents of the source file into it using
572C<aio_sendfile>, followed by restoring atime, mtime, access mode and 789C<aio_sendfile>, followed by restoring atime, mtime, access mode and
573uid/gid, in that order. 790uid/gid, in that order.
574 791
575If an error occurs, the partial destination file will be unlinked, if 792If an error occurs, the partial destination file will be unlinked, if
… …
585 my $grp = aio_group $cb; 802 my $grp = aio_group $cb;
586 803
587 aioreq_pri $pri; 804 aioreq_pri $pri;
588 add $grp aio_open $src, O_RDONLY, 0, sub { 805 add $grp aio_open $src, O_RDONLY, 0, sub {
589 if (my $src_fh = $_[0]) { 806 if (my $src_fh = $_[0]) {
590 my @stat = stat $src_fh; 807 my @stat = stat $src_fh; # hmm, might block over nfs?
591 808
592 aioreq_pri $pri; 809 aioreq_pri $pri;
593 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 810 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
594 if (my $dst_fh = $_[0]) { 811 if (my $dst_fh = $_[0]) {
595 aioreq_pri $pri; 812 aioreq_pri $pri;
596 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 813 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
597 if ($_[0] == $stat[7]) { 814 if ($_[0] == $stat[7]) {
598 $grp->result (0); 815 $grp->result (0);
599 close $src_fh; 816 close $src_fh;
600 817
601 # those should not normally block. should. should. 818 my $ch = sub {
602 utime $stat[8], $stat[9], $dst; 819 aioreq_pri $pri;
603 chmod $stat[2] & 07777, $dst_fh; 820 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
604 chown $stat[4], $stat[5], $dst_fh; 821 aioreq_pri $pri;
822 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
823 aioreq_pri $pri;
824 add $grp aio_close $dst_fh;
825 }
826 };
827 };
605 828
606 aioreq_pri $pri; 829 aioreq_pri $pri;
607 add $grp aio_close $dst_fh; 830 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
831 if ($_[0] < 0 && $! == ENOSYS) {
832 aioreq_pri $pri;
833 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
834 } else {
835 $ch->();
836 }
837 };
608 } else { 838 } else {
609 $grp->result (-1); 839 $grp->result (-1);
610 close $src_fh; 840 close $src_fh;
611 close $dst_fh; 841 close $dst_fh;
612 842
… …
629 859
630=item aio_move $srcpath, $dstpath, $callback->($status) 860=item aio_move $srcpath, $dstpath, $callback->($status)
631 861
632Try to move the I<file> (directories not supported as either source or 862Try to move the I<file> (directories not supported as either source or
633destination) from C<$srcpath> to C<$dstpath> and call the callback with 863destination) from C<$srcpath> to C<$dstpath> and call the callback with
634the C<0> (error) or C<-1> ok. 864a status of C<0> (ok) or C<-1> (error, see C<$!>).
635 865
636This is a composite request that tries to rename(2) the file first. If 866This is a composite request that tries to rename(2) the file first; if
637rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 867rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
638that is successful, unlinking the C<$srcpath>. 868that is successful, unlinks the C<$srcpath>.
639 869
640=cut 870=cut
641 871
642sub aio_move($$;$) { 872sub aio_move($$;$) {
643 my ($src, $dst, $cb) = @_; 873 my ($src, $dst, $cb) = @_;
… …
650 if ($_[0] && $! == EXDEV) { 880 if ($_[0] && $! == EXDEV) {
651 aioreq_pri $pri; 881 aioreq_pri $pri;
652 add $grp aio_copy $src, $dst, sub { 882 add $grp aio_copy $src, $dst, sub {
653 $grp->result ($_[0]); 883 $grp->result ($_[0]);
654 884
655 if (!$_[0]) { 885 unless ($_[0]) {
656 aioreq_pri $pri; 886 aioreq_pri $pri;
657 add $grp aio_unlink $src; 887 add $grp aio_unlink $src;
658 } 888 }
659 }; 889 };
660 } else { 890 } else {
… …
690 920
691Implementation notes. 921Implementation notes.
692 922
693The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 923The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
694 924
925If readdir returns file type information, then this is used directly to
926find directories.
927
695After reading the directory, the modification time, size etc. of the 928Otherwise, after reading the directory, the modification time, size etc.
696directory before and after the readdir is checked, and if they match (and 929of 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 930match (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 931how many entries are directories (if >= 2). Otherwise, no knowledge of the
699of subdirectories will be assumed. 932number of subdirectories will be assumed.
700 933
701Then entries will be sorted into likely directories (everything without 934Then entries will be sorted into likely directories a non-initial dot
702a non-initial dot currently) and likely non-directories (everything 935currently) and likely non-directories (see C<aio_readdirx>). Then every
703else). Then every entry plus an appended C</.> will be C<stat>'ed, 936entry plus an appended C</.> will be C<stat>'ed, likely directories first,
704likely directories first. If that succeeds, it assumes that the entry 937in order of their inode numbers. If that succeeds, it assumes that the
705is a directory or a symlink to directory (which will be checked 938entry is a directory or a symlink to directory (which will be checked
706seperately). This is often faster than stat'ing the entry itself because 939seperately). This is often faster than stat'ing the entry itself because
707filesystems might detect the type of the entry without reading the inode 940filesystems might detect the type of the entry without reading the inode
708data (e.g. ext2fs filetype feature). 941data (e.g. ext2fs filetype feature), even on systems that cannot return
942the filetype information on readdir.
709 943
710If the known number of directories (link count - 2) has been reached, the 944If the known number of directories (link count - 2) has been reached, the
711rest of the entries is assumed to be non-directories. 945rest of the entries is assumed to be non-directories.
712 946
713This only works with certainty on POSIX (= UNIX) filesystems, which 947This only works with certainty on POSIX (= UNIX) filesystems, which
… …
735 my $now = time; 969 my $now = time;
736 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 970 my $hash1 = join ":", (stat _)[0,1,3,7,9];
737 971
738 # read the directory entries 972 # read the directory entries
739 aioreq_pri $pri; 973 aioreq_pri $pri;
740 add $grp aio_readdir $path, sub { 974 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
741 my $entries = shift 975 my $entries = shift
742 or return $grp->result (); 976 or return $grp->result ();
743 977
744 # stat the dir another time 978 # stat the dir another time
745 aioreq_pri $pri; 979 aioreq_pri $pri;
… …
751 # take the slow route if anything looks fishy 985 # take the slow route if anything looks fishy
752 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 986 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
753 $ndirs = -1; 987 $ndirs = -1;
754 } else { 988 } else {
755 # if nlink == 2, we are finished 989 # if nlink == 2, we are finished
756 # on non-posix-fs's, we rely on nlink < 2 990 # for non-posix-fs's, we rely on nlink < 2
757 $ndirs = (stat _)[3] - 2 991 $ndirs = (stat _)[3] - 2
758 or return $grp->result ([], $entries); 992 or return $grp->result ([], $entries);
759 } 993 }
760 994
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); 995 my (@dirs, @nondirs);
769 996
770 my $statgrp = add $grp aio_group sub { 997 my $statgrp = add $grp aio_group sub {
771 $grp->result (\@dirs, \@nondirs); 998 $grp->result (\@dirs, \@nondirs);
772 }; 999 };
773 1000
774 limit $statgrp $maxreq; 1001 limit $statgrp $maxreq;
775 feed $statgrp sub { 1002 feed $statgrp sub {
776 return unless @$entries; 1003 return unless @$entries;
777 my $entry = pop @$entries; 1004 my $entry = shift @$entries;
778 1005
779 aioreq_pri $pri; 1006 aioreq_pri $pri;
780 add $statgrp aio_stat "$path/$entry/.", sub { 1007 add $statgrp aio_stat "$path/$entry/.", sub {
781 if ($_[0] < 0) { 1008 if ($_[0] < 0) {
782 push @nondirs, $entry; 1009 push @nondirs, $entry;
… …
855callback with the fdatasync result code. 1082callback with the fdatasync result code.
856 1083
857If this call isn't available because your OS lacks it or it couldn't be 1084If 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. 1085detected, it will be emulated by calling C<fsync> instead.
859 1086
1087=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1088
1089Sync the data portion of the file specified by C<$offset> and C<$length>
1090to disk (but NOT the metadata), by calling the Linux-specific
1091sync_file_range call. If sync_file_range is not available or it returns
1092ENOSYS, then fdatasync or fsync is being substituted.
1093
1094C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1095C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1096C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1097manpage for details.
1098
860=item aio_pathsync $path, $callback->($status) 1099=item aio_pathsync $path, $callback->($status)
861 1100
862This request tries to open, fsync and close the given path. This is a 1101This request tries to open, fsync and close the given path. This is a
863composite request intended tosync directories after directory operations 1102composite request intended to sync directories after directory operations
864(E.g. rename). This might not work on all operating systems or have any 1103(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 1104specific effect, but usually it makes sure that directory changes get
866written to disc. It works for anything that can be opened for read-only, 1105written to disc. It works for anything that can be opened for read-only,
867not just directories. 1106not just directories.
1107
1108Future versions of this function might fall back to other methods when
1109C<fsync> on the directory fails (such as calling C<sync>).
868 1110
869Passes C<0> when everything went ok, and C<-1> on error. 1111Passes C<0> when everything went ok, and C<-1> on error.
870 1112
871=cut 1113=cut
872 1114
… …
893 }; 1135 };
894 1136
895 $grp 1137 $grp
896} 1138}
897 1139
1140=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1141
1142This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1143scalars (see the C<IO::AIO::mmap> function, although it also works on data
1144scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1145scalar must only be modified in-place while an aio operation is pending on
1146it).
1147
1148It calls the C<msync> function of your OS, if available, with the memory
1149area starting at C<$offset> in the string and ending C<$length> bytes
1150later. If C<$length> is negative, counts from the end, and if C<$length>
1151is C<undef>, then it goes till the end of the string. The flags can be
1152a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1153C<IO::AIO::MS_SYNC>.
1154
1155=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1156
1157This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1158scalars.
1159
1160It touches (reads or writes) all memory pages in the specified
1161range inside the scalar. All caveats and parameters are the same
1162as for C<aio_msync>, above, except for flags, which must be either
1163C<0> (which reads all pages and ensures they are instantiated) or
1164C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1165writing an octet from it, which dirties the page).
1166
1167=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1168
1169This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170scalars.
1171
1172It reads in all the pages of the underlying storage into memory (if any)
1173and locks them, so they are not getting swapped/paged out or removed.
1174
1175If C<$length> is undefined, then the scalar will be locked till the end.
1176
1177On systems that do not implement C<mlock>, this function returns C<-1>
1178and sets errno to C<ENOSYS>.
1179
1180Note that the corresponding C<munlock> is synchronous and is
1181documented under L<MISCELLANEOUS FUNCTIONS>.
1182
1183Example: open a file, mmap and mlock it - both will be undone when
1184C<$data> gets destroyed.
1185
1186 open my $fh, "<", $path or die "$path: $!";
1187 my $data;
1188 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1189 aio_mlock $data; # mlock in background
1190
1191=item aio_mlockall $flags, $callback->($status)
1192
1193Calls the C<mlockall> function with the given C<$flags> (a combination of
1194C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1195
1196On systems that do not implement C<mlockall>, this function returns C<-1>
1197and sets errno to C<ENOSYS>.
1198
1199Note that the corresponding C<munlockall> is synchronous and is
1200documented under L<MISCELLANEOUS FUNCTIONS>.
1201
1202Example: asynchronously lock all current and future pages into memory.
1203
1204 aio_mlockall IO::AIO::MCL_FUTURE;
1205
898=item aio_group $callback->(...) 1206=item aio_group $callback->(...)
899 1207
900This is a very special aio request: Instead of doing something, it is a 1208This 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 1209container for other aio requests, which is useful if you want to bundle
902many requests into a single, composite, request with a definite callback 1210many requests into a single, composite, request with a definite callback
… …
951=item cancel $req 1259=item cancel $req
952 1260
953Cancels the request, if possible. Has the effect of skipping execution 1261Cancels the request, if possible. Has the effect of skipping execution
954when entering the B<execute> state and skipping calling the callback when 1262when entering the B<execute> state and skipping calling the callback when
955entering the the B<result> state, but will leave the request otherwise 1263entering the the B<result> state, but will leave the request otherwise
956untouched. That means that requests that currently execute will not be 1264untouched (with the exception of readdir). That means that requests that
957stopped and resources held by the request will not be freed prematurely. 1265currently execute will not be stopped and resources held by the request
1266will not be freed prematurely.
958 1267
959=item cb $req $callback->(...) 1268=item cb $req $callback->(...)
960 1269
961Replace (or simply set) the callback registered to the request. 1270Replace (or simply set) the callback registered to the request.
962 1271
… …
1013Their lifetime, simplified, looks like this: when they are empty, they 1322Their lifetime, simplified, looks like this: when they are empty, they
1014will finish very quickly. If they contain only requests that are in the 1323will finish very quickly. If they contain only requests that are in the
1015C<done> state, they will also finish. Otherwise they will continue to 1324C<done> state, they will also finish. Otherwise they will continue to
1016exist. 1325exist.
1017 1326
1018That means after creating a group you have some time to add requests. And 1327That means after creating a group you have some time to add requests
1019in the callbacks of those requests, you can add further requests to the 1328(precisely before the callback has been invoked, which is only done within
1020group. And only when all those requests have finished will the the group 1329the C<poll_cb>). And in the callbacks of those requests, you can add
1021itself finish. 1330further requests to the group. And only when all those requests have
1331finished will the the group itself finish.
1022 1332
1023=over 4 1333=over 4
1024 1334
1025=item add $grp ... 1335=item add $grp ...
1026 1336
… …
1034 1344
1035=item $grp->cancel_subs 1345=item $grp->cancel_subs
1036 1346
1037Cancel all subrequests and clears any feeder, but not the group request 1347Cancel all subrequests and clears any feeder, but not the group request
1038itself. Useful when you queued a lot of events but got a result early. 1348itself. Useful when you queued a lot of events but got a result early.
1349
1350The group request will finish normally (you cannot add requests to the
1351group).
1039 1352
1040=item $grp->result (...) 1353=item $grp->result (...)
1041 1354
1042Set the result value(s) that will be passed to the group callback when all 1355Set the result value(s) that will be passed to the group callback when all
1043subrequests have finished and set the groups errno to the current value 1356subrequests have finished and set the groups errno to the current value
… …
1059=item feed $grp $callback->($grp) 1372=item feed $grp $callback->($grp)
1060 1373
1061Sets a feeder/generator on this group: every group can have an attached 1374Sets a feeder/generator on this group: every group can have an attached
1062generator that generates requests if idle. The idea behind this is that, 1375generator that generates requests if idle. The idea behind this is that,
1063although you could just queue as many requests as you want in a group, 1376although you could just queue as many requests as you want in a group,
1064this might starve other requests for a potentially long time. For 1377this might starve other requests for a potentially long time. For example,
1065example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1378C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1066requests, delaying any later requests for a long time. 1379delaying any later requests for a long time.
1067 1380
1068To avoid this, and allow incremental generation of requests, you can 1381To avoid this, and allow incremental generation of requests, you can
1069instead a group and set a feeder on it that generates those requests. The 1382instead a group and set a feeder on it that generates those requests. The
1070feed callback will be called whenever there are few enough (see C<limit>, 1383feed callback will be called whenever there are few enough (see C<limit>,
1071below) requests active in the group itself and is expected to queue more 1384below) requests active in the group itself and is expected to queue more
… …
1075not impose any limits). 1388not impose any limits).
1076 1389
1077If the feed does not queue more requests when called, it will be 1390If the feed does not queue more requests when called, it will be
1078automatically removed from the group. 1391automatically removed from the group.
1079 1392
1080If the feed limit is C<0>, it will be set to C<2> automatically. 1393If the feed limit is C<0> when this method is called, it will be set to
1394C<2> automatically.
1081 1395
1082Example: 1396Example:
1083 1397
1084 # stat all files in @files, but only ever use four aio requests concurrently: 1398 # stat all files in @files, but only ever use four aio requests concurrently:
1085 1399
… …
1097Sets the feeder limit for the group: The feeder will be called whenever 1411Sets the feeder limit for the group: The feeder will be called whenever
1098the group contains less than this many requests. 1412the group contains less than this many requests.
1099 1413
1100Setting the limit to C<0> will pause the feeding process. 1414Setting the limit to C<0> will pause the feeding process.
1101 1415
1416The default value for the limit is C<0>, but note that setting a feeder
1417automatically bumps it up to C<2>.
1418
1102=back 1419=back
1103 1420
1104=head2 SUPPORT FUNCTIONS 1421=head2 SUPPORT FUNCTIONS
1105 1422
1106=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1423=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1108=over 4 1425=over 4
1109 1426
1110=item $fileno = IO::AIO::poll_fileno 1427=item $fileno = IO::AIO::poll_fileno
1111 1428
1112Return the I<request result pipe file descriptor>. This filehandle must be 1429Return the I<request result pipe file descriptor>. This filehandle must be
1113polled for reading by some mechanism outside this module (e.g. Event or 1430polled for reading by some mechanism outside this module (e.g. EV, Glib,
1114select, see below or the SYNOPSIS). If the pipe becomes readable you have 1431select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1115to call C<poll_cb> to check the results. 1432you have to call C<poll_cb> to check the results.
1116 1433
1117See C<poll_cb> for an example. 1434See C<poll_cb> for an example.
1118 1435
1119=item IO::AIO::poll_cb 1436=item IO::AIO::poll_cb
1120 1437
1121Process some outstanding events on the result pipe. You have to call this 1438Process some outstanding events on the result pipe. You have to call
1122regularly. Returns the number of events processed. Returns immediately 1439this regularly. Returns C<0> if all events could be processed (or there
1123when no events are outstanding. The amount of events processed depends on 1440were no events to process), or C<-1> if it returned earlier for whatever
1124the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1441reason. Returns immediately when no events are outstanding. The amount of
1442events processed depends on the settings of C<IO::AIO::max_poll_req> and
1443C<IO::AIO::max_poll_time>.
1125 1444
1126If not all requests were processed for whatever reason, the filehandle 1445If not all requests were processed for whatever reason, the filehandle
1127will still be ready when C<poll_cb> returns. 1446will still be ready when C<poll_cb> returns, so normally you don't have to
1447do anything special to have it called later.
1448
1449Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1450ready, it can be beneficial to call this function from loops which submit
1451a lot of requests, to make sure the results get processed when they become
1452available and not just when the loop is finished and the event loop takes
1453over again. This function returns very fast when there are no outstanding
1454requests.
1128 1455
1129Example: Install an Event watcher that automatically calls 1456Example: Install an Event watcher that automatically calls
1130IO::AIO::poll_cb with high priority: 1457IO::AIO::poll_cb with high priority (more examples can be found in the
1458SYNOPSIS section, at the top of this document):
1131 1459
1132 Event->io (fd => IO::AIO::poll_fileno, 1460 Event->io (fd => IO::AIO::poll_fileno,
1133 poll => 'r', async => 1, 1461 poll => 'r', async => 1,
1134 cb => \&IO::AIO::poll_cb); 1462 cb => \&IO::AIO::poll_cb);
1463
1464=item IO::AIO::poll_wait
1465
1466If there are any outstanding requests and none of them in the result
1467phase, wait till the result filehandle becomes ready for reading (simply
1468does a C<select> on the filehandle. This is useful if you want to
1469synchronously wait for some requests to finish).
1470
1471See C<nreqs> for an example.
1472
1473=item IO::AIO::poll
1474
1475Waits until some requests have been handled.
1476
1477Returns the number of requests processed, but is otherwise strictly
1478equivalent to:
1479
1480 IO::AIO::poll_wait, IO::AIO::poll_cb
1481
1482=item IO::AIO::flush
1483
1484Wait till all outstanding AIO requests have been handled.
1485
1486Strictly equivalent to:
1487
1488 IO::AIO::poll_wait, IO::AIO::poll_cb
1489 while IO::AIO::nreqs;
1135 1490
1136=item IO::AIO::max_poll_reqs $nreqs 1491=item IO::AIO::max_poll_reqs $nreqs
1137 1492
1138=item IO::AIO::max_poll_time $seconds 1493=item IO::AIO::max_poll_time $seconds
1139 1494
… …
1164 # use a low priority so other tasks have priority 1519 # use a low priority so other tasks have priority
1165 Event->io (fd => IO::AIO::poll_fileno, 1520 Event->io (fd => IO::AIO::poll_fileno,
1166 poll => 'r', nice => 1, 1521 poll => 'r', nice => 1,
1167 cb => &IO::AIO::poll_cb); 1522 cb => &IO::AIO::poll_cb);
1168 1523
1169=item IO::AIO::poll_wait
1170
1171If there are any outstanding requests and none of them in the result
1172phase, wait till the result filehandle becomes ready for reading (simply
1173does a C<select> on the filehandle. This is useful if you want to
1174synchronously wait for some requests to finish).
1175
1176See C<nreqs> for an example.
1177
1178=item IO::AIO::poll
1179
1180Waits until some requests have been handled.
1181
1182Returns the number of requests processed, but is otherwise strictly
1183equivalent to:
1184
1185 IO::AIO::poll_wait, IO::AIO::poll_cb
1186
1187=item IO::AIO::flush
1188
1189Wait till all outstanding AIO requests have been handled.
1190
1191Strictly equivalent to:
1192
1193 IO::AIO::poll_wait, IO::AIO::poll_cb
1194 while IO::AIO::nreqs;
1195
1196=back 1524=back
1197 1525
1198=head3 CONTROLLING THE NUMBER OF THREADS 1526=head3 CONTROLLING THE NUMBER OF THREADS
1199 1527
1200=over 1528=over
… …
1233 1561
1234Under normal circumstances you don't need to call this function. 1562Under normal circumstances you don't need to call this function.
1235 1563
1236=item IO::AIO::max_idle $nthreads 1564=item IO::AIO::max_idle $nthreads
1237 1565
1238Limit the number of threads (default: 4) that are allowed to idle (i.e., 1566Limit the number of threads (default: 4) that are allowed to idle
1239threads that did not get a request to process within 10 seconds). That 1567(i.e., threads that did not get a request to process within the idle
1240means if a thread becomes idle while C<$nthreads> other threads are also 1568timeout (default: 10 seconds). That means if a thread becomes idle while
1241idle, it will free its resources and exit. 1569C<$nthreads> other threads are also idle, it will free its resources and
1570exit.
1242 1571
1243This is useful when you allow a large number of threads (e.g. 100 or 1000) 1572This is useful when you allow a large number of threads (e.g. 100 or 1000)
1244to allow for extremely high load situations, but want to free resources 1573to allow for extremely high load situations, but want to free resources
1245under normal circumstances (1000 threads can easily consume 30MB of RAM). 1574under normal circumstances (1000 threads can easily consume 30MB of RAM).
1246 1575
1247The default is probably ok in most situations, especially if thread 1576The default is probably ok in most situations, especially if thread
1248creation is fast. If thread creation is very slow on your system you might 1577creation is fast. If thread creation is very slow on your system you might
1249want to use larger values. 1578want to use larger values.
1250 1579
1580=item IO::AIO::idle_timeout $seconds
1581
1582Sets the minimum idle timeout (default 10) after which worker threads are
1583allowed to exit. SEe C<IO::AIO::max_idle>.
1584
1251=item IO::AIO::max_outstanding $maxreqs 1585=item IO::AIO::max_outstanding $maxreqs
1586
1587Sets the maximum number of outstanding requests to C<$nreqs>. If
1588you do queue up more than this number of requests, the next call to
1589C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1590C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1591longer exceeded.
1592
1593In other words, this setting does not enforce a queue limit, but can be
1594used to make poll functions block if the limit is exceeded.
1252 1595
1253This is a very bad function to use in interactive programs because it 1596This is a very bad function to use in interactive programs because it
1254blocks, and a bad way to reduce concurrency because it is inexact: Better 1597blocks, and a bad way to reduce concurrency because it is inexact: Better
1255use an C<aio_group> together with a feed callback. 1598use an C<aio_group> together with a feed callback.
1256 1599
1257Sets the maximum number of outstanding requests to C<$nreqs>. If you 1600It's main use is in scripts without an event loop - when you want to stat
1258do queue up more than this number of requests, the next call to the 1601a lot of files, you can write somehting like this:
1259C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1260function will block until the limit is no longer exceeded.
1261 1602
1262The default value is very large, so there is no practical limit on the 1603 IO::AIO::max_outstanding 32;
1263number of outstanding requests.
1264 1604
1265You can still queue as many requests as you want. Therefore, 1605 for my $path (...) {
1266C<max_outstanding> is mainly useful in simple scripts (with low values) or 1606 aio_stat $path , ...;
1267as a stop gap to shield against fatal memory overflow (with large values). 1607 IO::AIO::poll_cb;
1608 }
1609
1610 IO::AIO::flush;
1611
1612The call to C<poll_cb> inside the loop will normally return instantly, but
1613as soon as more thna C<32> reqeusts are in-flight, it will block until
1614some requests have been handled. This keeps the loop from pushing a large
1615number of C<aio_stat> requests onto the queue.
1616
1617The default value for C<max_outstanding> is very large, so there is no
1618practical limit on the number of outstanding requests.
1268 1619
1269=back 1620=back
1270 1621
1271=head3 STATISTICAL INFORMATION 1622=head3 STATISTICAL INFORMATION
1272 1623
… …
1292Returns the number of requests currently in the pending state (executed, 1643Returns the number of requests currently in the pending state (executed,
1293but not yet processed by poll_cb). 1644but not yet processed by poll_cb).
1294 1645
1295=back 1646=back
1296 1647
1648=head3 MISCELLANEOUS FUNCTIONS
1649
1650IO::AIO implements some functions that might be useful, but are not
1651asynchronous.
1652
1653=over 4
1654
1655=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1656
1657Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1658but is blocking (this makes most sense if you know the input data is
1659likely cached already and the output filehandle is set to non-blocking
1660operations).
1661
1662Returns the number of bytes copied, or C<-1> on error.
1663
1664=item IO::AIO::fadvise $fh, $offset, $len, $advice
1665
1666Simply calls the C<posix_fadvise> function (see its
1667manpage for details). The following advice constants are
1668avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1669C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1670C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1671
1672On systems that do not implement C<posix_fadvise>, this function returns
1673ENOSYS, otherwise the return value of C<posix_fadvise>.
1674
1675=item IO::AIO::madvise $scalar, $offset, $len, $advice
1676
1677Simply calls the C<posix_madvise> function (see its
1678manpage for details). The following advice constants are
1679avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1680C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1681
1682On systems that do not implement C<posix_madvise>, this function returns
1683ENOSYS, otherwise the return value of C<posix_madvise>.
1684
1685=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1686
1687Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1688$scalar (see its manpage for details). The following protect
1689constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1690C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1691
1692On systems that do not implement C<mprotect>, this function returns
1693ENOSYS, otherwise the return value of C<mprotect>.
1694
1695=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1696
1697Memory-maps a file (or anonymous memory range) and attaches it to the
1698given C<$scalar>, which will act like a string scalar.
1699
1700The only operations allowed on the scalar are C<substr>/C<vec> that don't
1701change the string length, and most read-only operations such as copying it
1702or searching it with regexes and so on.
1703
1704Anything else is unsafe and will, at best, result in memory leaks.
1705
1706The memory map associated with the C<$scalar> is automatically removed
1707when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1708C<IO::AIO::munmap> functions are called.
1709
1710This calls the C<mmap>(2) function internally. See your system's manual
1711page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1712
1713The C<$length> must be larger than zero and smaller than the actual
1714filesize.
1715
1716C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1717C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1718
1719C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1720C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1721not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1722(which is set to C<MAP_ANON> if your system only provides this
1723constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1724C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1725C<IO::AIO::MAP_NONBLOCK>
1726
1727If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1728
1729C<$offset> is the offset from the start of the file - it generally must be
1730a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1731
1732Example:
1733
1734 use Digest::MD5;
1735 use IO::AIO;
1736
1737 open my $fh, "<verybigfile"
1738 or die "$!";
1739
1740 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1741 or die "verybigfile: $!";
1742
1743 my $fast_md5 = md5 $data;
1744
1745=item IO::AIO::munmap $scalar
1746
1747Removes a previous mmap and undefines the C<$scalar>.
1748
1749=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1750
1751Calls the C<munlock> function, undoing the effects of a previous
1752C<aio_mlock> call (see its description for details).
1753
1754=item IO::AIO::munlockall
1755
1756Calls the C<munlockall> function.
1757
1758On systems that do not implement C<munlockall>, this function returns
1759ENOSYS, otherwise the return value of C<munlockall>.
1760
1761=back
1762
1297=cut 1763=cut
1298 1764
1299min_parallel 8; 1765min_parallel 8;
1300 1766
1301END { flush } 1767END { flush }
1302 1768
13031; 17691;
1304 1770
1771=head1 EVENT LOOP INTEGRATION
1772
1773It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1774automatically into many event loops:
1775
1776 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1777 use AnyEvent::AIO;
1778
1779You can also integrate IO::AIO manually into many event loops, here are
1780some examples of how to do this:
1781
1782 # EV integration
1783 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1784
1785 # Event integration
1786 Event->io (fd => IO::AIO::poll_fileno,
1787 poll => 'r',
1788 cb => \&IO::AIO::poll_cb);
1789
1790 # Glib/Gtk2 integration
1791 add_watch Glib::IO IO::AIO::poll_fileno,
1792 in => sub { IO::AIO::poll_cb; 1 };
1793
1794 # Tk integration
1795 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1796 readable => \&IO::AIO::poll_cb);
1797
1798 # Danga::Socket integration
1799 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1800 \&IO::AIO::poll_cb);
1801
1305=head2 FORK BEHAVIOUR 1802=head2 FORK BEHAVIOUR
1306 1803
1307This module should do "the right thing" when the process using it forks: 1804Usage of pthreads in a program changes the semantics of fork
1805considerably. Specifically, only async-safe functions can be called after
1806fork. Perl doesn't know about this, so in general, you cannot call fork
1807with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1808but many other extensions and (for inexplicable reasons) perl itself often
1809is linked against pthreads, so this limitation applies.
1308 1810
1309Before the fork, IO::AIO enters a quiescent state where no requests 1811Some operating systems have extensions that allow safe use of fork, and
1310can be added in other threads and no results will be processed. After 1812this module should do "the right thing" on those, and tries on others. At
1311the fork the parent simply leaves the quiescent state and continues 1813the time of this writing (2011) only GNU/Linux supports these extensions
1312request/result processing, while the child frees the request/result queue 1814to POSIX.
1313(so that the requests started before the fork will only be handled in the
1314parent). Threads will be started on demand until the limit set in the
1315parent process has been reached again.
1316
1317In short: the parent will, after a short pause, continue as if fork had
1318not been called, while the child will act as if IO::AIO has not been used
1319yet.
1320 1815
1321=head2 MEMORY USAGE 1816=head2 MEMORY USAGE
1322 1817
1323Per-request usage: 1818Per-request usage:
1324 1819

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