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Revision 1.126 by root, Sun May 11 01:08:05 2008 UTC vs.
Revision 1.208 by root, Mon Sep 26 20:19:08 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 = '3.01'; 173 our $VERSION = '4.0';
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
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
203 aio_fdatasync aio_pathsync aio_readahead 179 aio_pathsync aio_readahead
204 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
205 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
206 aio_chmod aio_utime aio_truncate); 182 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs
185 aio_wd);
207 186
208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
211 nreqs nready npending nthreads 190 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs); 191 max_poll_time max_poll_reqs
192 sendfile fadvise madvise
193 mmap munmap munlock munlockall);
194
195 push @AIO_REQ, qw(aio_busy); # not exported
213 196
214 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
215 198
216 require XSLoader; 199 require XSLoader;
217 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
218} 201}
219 202
220=head1 FUNCTIONS 203=head1 FUNCTIONS
204
205=head2 QUICK OVERVIEW
206
207This section simply lists the prototypes of the most important functions
208for quick reference. See the following sections for function-by-function
209documentation.
210
211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_unlink $pathname, $callback->($status)
226 aio_mknod $path, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $path, $callback->($link)
230 aio_realpath $path, $callback->($link)
231 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
238 aio_load $path, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $path, $callback->($status)
243 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $path, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...)
254 aio_nop $callback->()
255
256 $prev_pri = aioreq_pri [$pri]
257 aioreq_nice $pri_adjust
258
259 IO::AIO::poll_wait
260 IO::AIO::poll_cb
261 IO::AIO::poll
262 IO::AIO::flush
263 IO::AIO::max_poll_reqs $nreqs
264 IO::AIO::max_poll_time $seconds
265 IO::AIO::min_parallel $nthreads
266 IO::AIO::max_parallel $nthreads
267 IO::AIO::max_idle $nthreads
268 IO::AIO::idle_timeout $seconds
269 IO::AIO::max_outstanding $maxreqs
270 IO::AIO::nreqs
271 IO::AIO::nready
272 IO::AIO::npending
273
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice
276 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall
221 280
222=head2 AIO REQUEST FUNCTIONS 281=head2 AIO REQUEST FUNCTIONS
223 282
224All the C<aio_*> calls are more or less thin wrappers around the syscall 283All the C<aio_*> calls are more or less thin wrappers around the syscall
225with the same name (sans C<aio_>). The arguments are similar or identical, 284with the same name (sans C<aio_>). The arguments are similar or identical,
226and they all accept an additional (and optional) C<$callback> argument 285and they all accept an additional (and optional) C<$callback> argument
227which must be a code reference. This code reference will get called with 286which 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 287the 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 288perl, which usually delivers "false") as its sole argument after the given
230syscall has been executed asynchronously. 289syscall has been executed asynchronously.
231 290
232All functions expecting a filehandle keep a copy of the filehandle 291All functions expecting a filehandle keep a copy of the filehandle
233internally until the request has finished. 292internally until the request has finished.
234 293
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248your pathnames to the locale (or other) encoding in effect in the user 307your pathnames to the locale (or other) encoding in effect in the user
249environment, d) use Glib::filename_from_unicode on unicode filenames or e) 308environment, d) use Glib::filename_from_unicode on unicode filenames or e)
250use something else to ensure your scalar has the correct contents. 309use something else to ensure your scalar has the correct contents.
251 310
252This works, btw. independent of the internal UTF-8 bit, which IO::AIO 311This works, btw. independent of the internal UTF-8 bit, which IO::AIO
253handles correctly wether it is set or not. 312handles correctly whether it is set or not.
254 313
255=over 4 314=over 4
256 315
257=item $prev_pri = aioreq_pri [$pri] 316=item $prev_pri = aioreq_pri [$pri]
258 317
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305by the umask in effect then the request is being executed, so better never 364by the umask in effect then the request is being executed, so better never
306change the umask. 365change the umask.
307 366
308Example: 367Example:
309 368
310 aio_open "/etc/passwd", O_RDONLY, 0, sub { 369 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
311 if ($_[0]) { 370 if ($_[0]) {
312 print "open successful, fh is $_[0]\n"; 371 print "open successful, fh is $_[0]\n";
313 ... 372 ...
314 } else { 373 } else {
315 die "open failed: $!\n"; 374 die "open failed: $!\n";
316 } 375 }
317 }; 376 };
318 377
378In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
379C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
380following POSIX and non-POSIX constants are available (missing ones on
381your system are, as usual, C<0>):
382
383C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
384C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
385C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
386
319 387
320=item aio_close $fh, $callback->($status) 388=item aio_close $fh, $callback->($status)
321 389
322Asynchronously close a file and call the callback with the result 390Asynchronously close a file and call the callback with the result
323code. 391code.
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336 404
337=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 405=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
338 406
339=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 407=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
340 408
341Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 409Reads or writes C<$length> bytes from or to the specified C<$fh> and
342into the scalar given by C<$data> and offset C<$dataoffset> and calls the 410C<$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 411and calls the callback without the actual number of bytes read (or -1 on
344like the syscall). 412error, just like the syscall).
413
414C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
415offset plus the actual number of bytes read.
345 416
346If C<$offset> is undefined, then the current file descriptor offset will 417If C<$offset> is undefined, then the current file descriptor offset will
347be used (and updated), otherwise the file descriptor offset will not be 418be used (and updated), otherwise the file descriptor offset will not be
348changed by these calls. 419changed by these calls.
349 420
350If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 421If C<$length> is undefined in C<aio_write>, use the remaining length of
422C<$data>.
351 423
352If C<$dataoffset> is less than zero, it will be counted from the end of 424If C<$dataoffset> is less than zero, it will be counted from the end of
353C<$data>. 425C<$data>.
354 426
355The C<$data> scalar I<MUST NOT> be modified in any way while the request 427The C<$data> scalar I<MUST NOT> be modified in any way while the request
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369 441
370Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 442Tries 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 443reading 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 444file 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 445than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
374other. 446other. The same C<$in_fh> works fine though, as this function does not
447move or use the file offset of C<$in_fh>.
375 448
449Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
450are written, and there is no way to find out how many more bytes have been
451read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
452number of bytes written to C<$out_fh>. Only if the result value equals
453C<$length> one can assume that C<$length> bytes have been read.
454
455Unlike with other C<aio_> functions, it makes a lot of sense to use
456C<aio_sendfile> on non-blocking sockets, as long as one end (typically
457the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
458the socket I/O will be non-blocking. Note, however, that you can run
459into a trap where C<aio_sendfile> reads some data with readahead, then
460fails to write all data, and when the socket is ready the next time, the
461data in the cache is already lost, forcing C<aio_sendfile> to again hit
462the disk. Explicit C<aio_read> + C<aio_write> let's you better control
463resource usage.
464
376This call tries to make use of a native C<sendfile> syscall to provide 465This call tries to make use of a native C<sendfile>-like syscall to
377zero-copy operation. For this to work, C<$out_fh> should refer to a 466provide zero-copy operation. For this to work, C<$out_fh> should refer to
378socket, and C<$in_fh> should refer to mmap'able file. 467a socket, and C<$in_fh> should refer to an mmap'able file.
379 468
380If the native sendfile call fails or is not implemented, it will be 469If 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 470C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
471C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
382regardless of the limitations of the operating system. 472type of filehandle regardless of the limitations of the operating system.
383 473
384Please note, however, that C<aio_sendfile> can read more bytes from 474As native sendfile syscalls (as practically any non-POSIX interface hacked
385C<$in_fh> than are written, and there is no way to find out how many 475together in a hurry to improve benchmark numbers) tend to be rather buggy
386bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 476on many systems, this implementation tries to work around some known bugs
387provides the number of bytes written to C<$out_fh>. Only if the result 477in Linux and FreeBSD kernels (probably others, too), but that might fail,
388value equals C<$length> one can assume that C<$length> bytes have been 478so you really really should check the return value of C<aio_sendfile> -
389read. 479fewre bytes than expected might have been transferred.
390 480
391 481
392=item aio_readahead $fh,$offset,$length, $callback->($retval) 482=item aio_readahead $fh,$offset,$length, $callback->($retval)
393 483
394C<aio_readahead> populates the page cache with data from a file so that 484C<aio_readahead> populates the page cache with data from a file so that
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417 507
418Currently, the stats are always 64-bit-stats, i.e. instead of returning an 508Currently, 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 509error when stat'ing a large file, the results will be silently truncated
420unless perl itself is compiled with large file support. 510unless perl itself is compiled with large file support.
421 511
512To help interpret the mode and dev/rdev stat values, IO::AIO offers the
513following constants and functions (if not implemented, the constants will
514be C<0> and the functions will either C<croak> or fall back on traditional
515behaviour).
516
517C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
518C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
519C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
520
422Example: Print the length of F</etc/passwd>: 521Example: Print the length of F</etc/passwd>:
423 522
424 aio_stat "/etc/passwd", sub { 523 aio_stat "/etc/passwd", sub {
425 $_[0] and die "stat failed: $!"; 524 $_[0] and die "stat failed: $!";
426 print "size is ", -s _, "\n"; 525 print "size is ", -s _, "\n";
427 }; 526 };
428 527
429 528
529=item aio_statvfs $fh_or_path, $callback->($statvfs)
530
531Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
532whether a file handle or path was passed.
533
534On success, the callback is passed a hash reference with the following
535members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
536C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
537is passed.
538
539The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
540C<ST_NOSUID>.
541
542The following non-POSIX IO::AIO::ST_* flag masks are defined to
543their correct value when available, or to C<0> on systems that do
544not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
545C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
546C<ST_NODIRATIME> and C<ST_RELATIME>.
547
548Example: stat C</wd> and dump out the data if successful.
549
550 aio_statvfs "/wd", sub {
551 my $f = $_[0]
552 or die "statvfs: $!";
553
554 use Data::Dumper;
555 say Dumper $f;
556 };
557
558 # result:
559 {
560 bsize => 1024,
561 bfree => 4333064312,
562 blocks => 10253828096,
563 files => 2050765568,
564 flag => 4096,
565 favail => 2042092649,
566 bavail => 4333064312,
567 ffree => 2042092649,
568 namemax => 255,
569 frsize => 1024,
570 fsid => 1810
571 }
572
573
430=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 574=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
431 575
432Works like perl's C<utime> function (including the special case of $atime 576Works like perl's C<utime> function (including the special case of $atime
433and $mtime being undef). Fractional times are supported if the underlying 577and $mtime being undef). Fractional times are supported if the underlying
434syscalls support them. 578syscalls support them.
… …
482 626
483The only (POSIX-) portable way of calling this function is: 627The only (POSIX-) portable way of calling this function is:
484 628
485 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 629 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
486 630
631See C<aio_stat> for info about some potentially helpful extra constants
632and functions.
487 633
488=item aio_link $srcpath, $dstpath, $callback->($status) 634=item aio_link $srcpath, $dstpath, $callback->($status)
489 635
490Asynchronously create a new link to the existing object at C<$srcpath> at 636Asynchronously create a new link to the existing object at C<$srcpath> at
491the path C<$dstpath> and call the callback with the result code. 637the path C<$dstpath> and call the callback with the result code.
… …
502Asynchronously read the symlink specified by C<$path> and pass it to 648Asynchronously read the symlink specified by C<$path> and pass it to
503the callback. If an error occurs, nothing or undef gets passed to the 649the callback. If an error occurs, nothing or undef gets passed to the
504callback. 650callback.
505 651
506 652
653=item aio_realpath $path, $callback->($path)
654
655Asynchronously make the path absolute and resolve any symlinks in
656C<$path>. The resulting path only consists of directories (Same as
657L<Cwd::realpath>).
658
659This request can be used to get the absolute path of the current working
660directory by passing it a path of F<.> (a single dot).
661
662
507=item aio_rename $srcpath, $dstpath, $callback->($status) 663=item aio_rename $srcpath, $dstpath, $callback->($status)
508 664
509Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 665Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
510rename(2) and call the callback with the result code. 666rename(2) and call the callback with the result code.
511 667
… …
527 683
528Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 684Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
529directory (i.e. opendir + readdir + closedir). The entries will not be 685directory (i.e. opendir + readdir + closedir). The entries will not be
530sorted, and will B<NOT> include the C<.> and C<..> entries. 686sorted, and will B<NOT> include the C<.> and C<..> entries.
531 687
532The callback a single argument which is either C<undef> or an array-ref 688The callback is passed a single argument which is either C<undef> or an
533with the filenames. 689array-ref with the filenames.
690
691
692=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
693
694Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
695tune behaviour and output format. In case of an error, C<$entries> will be
696C<undef>.
697
698The flags are a combination of the following constants, ORed together (the
699flags will also be passed to the callback, possibly modified):
700
701=over 4
702
703=item IO::AIO::READDIR_DENTS
704
705When this flag is off, then the callback gets an arrayref consisting of
706names only (as with C<aio_readdir>), otherwise it gets an arrayref with
707C<[$name, $type, $inode]> arrayrefs, each describing a single directory
708entry in more detail.
709
710C<$name> is the name of the entry.
711
712C<$type> is one of the C<IO::AIO::DT_xxx> constants:
713
714C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
715C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
716C<IO::AIO::DT_WHT>.
717
718C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
719know, you have to run stat yourself. Also, for speed reasons, the C<$type>
720scalars are read-only: you can not modify them.
721
722C<$inode> is the inode number (which might not be exact on systems with 64
723bit inode numbers and 32 bit perls). This field has unspecified content on
724systems that do not deliver the inode information.
725
726=item IO::AIO::READDIR_DIRS_FIRST
727
728When this flag is set, then the names will be returned in an order where
729likely directories come first, in optimal stat order. This is useful when
730you need to quickly find directories, or you want to find all directories
731while avoiding to stat() each entry.
732
733If the system returns type information in readdir, then this is used
734to find directories directly. Otherwise, likely directories are names
735beginning with ".", or otherwise names with no dots, of which names with
736short names are tried first.
737
738=item IO::AIO::READDIR_STAT_ORDER
739
740When this flag is set, then the names will be returned in an order
741suitable for stat()'ing each one. That is, when you plan to stat()
742all files in the given directory, then the returned order will likely
743be fastest.
744
745If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
746the likely dirs come first, resulting in a less optimal stat order.
747
748=item IO::AIO::READDIR_FOUND_UNKNOWN
749
750This flag should not be set when calling C<aio_readdirx>. Instead, it
751is being set by C<aio_readdirx>, when any of the C<$type>'s found were
752C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
753C<$type>'s are known, which can be used to speed up some algorithms.
754
755=back
534 756
535 757
536=item aio_load $path, $data, $callback->($status) 758=item aio_load $path, $data, $callback->($status)
537 759
538This is a composite request that tries to fully load the given file into 760This is a composite request that tries to fully load the given file into
… …
563 785
564=item aio_copy $srcpath, $dstpath, $callback->($status) 786=item aio_copy $srcpath, $dstpath, $callback->($status)
565 787
566Try to copy the I<file> (directories not supported as either source or 788Try to copy the I<file> (directories not supported as either source or
567destination) from C<$srcpath> to C<$dstpath> and call the callback with 789destination) from C<$srcpath> to C<$dstpath> and call the callback with
568the C<0> (error) or C<-1> ok. 790a status of C<0> (ok) or C<-1> (error, see C<$!>).
569 791
570This is a composite request that it creates the destination file with 792This is a composite request that creates the destination file with
571mode 0200 and copies the contents of the source file into it using 793mode 0200 and copies the contents of the source file into it using
572C<aio_sendfile>, followed by restoring atime, mtime, access mode and 794C<aio_sendfile>, followed by restoring atime, mtime, access mode and
573uid/gid, in that order. 795uid/gid, in that order.
574 796
575If an error occurs, the partial destination file will be unlinked, if 797If an error occurs, the partial destination file will be unlinked, if
… …
585 my $grp = aio_group $cb; 807 my $grp = aio_group $cb;
586 808
587 aioreq_pri $pri; 809 aioreq_pri $pri;
588 add $grp aio_open $src, O_RDONLY, 0, sub { 810 add $grp aio_open $src, O_RDONLY, 0, sub {
589 if (my $src_fh = $_[0]) { 811 if (my $src_fh = $_[0]) {
590 my @stat = stat $src_fh; 812 my @stat = stat $src_fh; # hmm, might block over nfs?
591 813
592 aioreq_pri $pri; 814 aioreq_pri $pri;
593 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 815 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
594 if (my $dst_fh = $_[0]) { 816 if (my $dst_fh = $_[0]) {
595 aioreq_pri $pri; 817 aioreq_pri $pri;
596 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 818 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
597 if ($_[0] == $stat[7]) { 819 if ($_[0] == $stat[7]) {
598 $grp->result (0); 820 $grp->result (0);
599 close $src_fh; 821 close $src_fh;
600 822
601 # those should not normally block. should. should. 823 my $ch = sub {
602 utime $stat[8], $stat[9], $dst; 824 aioreq_pri $pri;
603 chmod $stat[2] & 07777, $dst_fh; 825 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
604 chown $stat[4], $stat[5], $dst_fh; 826 aioreq_pri $pri;
827 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
828 aioreq_pri $pri;
829 add $grp aio_close $dst_fh;
830 }
831 };
832 };
605 833
606 aioreq_pri $pri; 834 aioreq_pri $pri;
607 add $grp aio_close $dst_fh; 835 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
836 if ($_[0] < 0 && $! == ENOSYS) {
837 aioreq_pri $pri;
838 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
839 } else {
840 $ch->();
841 }
842 };
608 } else { 843 } else {
609 $grp->result (-1); 844 $grp->result (-1);
610 close $src_fh; 845 close $src_fh;
611 close $dst_fh; 846 close $dst_fh;
612 847
… …
629 864
630=item aio_move $srcpath, $dstpath, $callback->($status) 865=item aio_move $srcpath, $dstpath, $callback->($status)
631 866
632Try to move the I<file> (directories not supported as either source or 867Try to move the I<file> (directories not supported as either source or
633destination) from C<$srcpath> to C<$dstpath> and call the callback with 868destination) from C<$srcpath> to C<$dstpath> and call the callback with
634the C<0> (error) or C<-1> ok. 869a status of C<0> (ok) or C<-1> (error, see C<$!>).
635 870
636This is a composite request that tries to rename(2) the file first. If 871This is a composite request that tries to rename(2) the file first; if
637rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 872rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
638that is successful, unlinking the C<$srcpath>. 873that is successful, unlinks the C<$srcpath>.
639 874
640=cut 875=cut
641 876
642sub aio_move($$;$) { 877sub aio_move($$;$) {
643 my ($src, $dst, $cb) = @_; 878 my ($src, $dst, $cb) = @_;
… …
650 if ($_[0] && $! == EXDEV) { 885 if ($_[0] && $! == EXDEV) {
651 aioreq_pri $pri; 886 aioreq_pri $pri;
652 add $grp aio_copy $src, $dst, sub { 887 add $grp aio_copy $src, $dst, sub {
653 $grp->result ($_[0]); 888 $grp->result ($_[0]);
654 889
655 if (!$_[0]) { 890 unless ($_[0]) {
656 aioreq_pri $pri; 891 aioreq_pri $pri;
657 add $grp aio_unlink $src; 892 add $grp aio_unlink $src;
658 } 893 }
659 }; 894 };
660 } else { 895 } else {
… …
690 925
691Implementation notes. 926Implementation notes.
692 927
693The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 928The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
694 929
930If readdir returns file type information, then this is used directly to
931find directories.
932
695After reading the directory, the modification time, size etc. of the 933Otherwise, after reading the directory, the modification time, size etc.
696directory before and after the readdir is checked, and if they match (and 934of 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 935match (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 936how many entries are directories (if >= 2). Otherwise, no knowledge of the
699of subdirectories will be assumed. 937number of subdirectories will be assumed.
700 938
701Then entries will be sorted into likely directories (everything without 939Then entries will be sorted into likely directories a non-initial dot
702a non-initial dot currently) and likely non-directories (everything 940currently) and likely non-directories (see C<aio_readdirx>). Then every
703else). Then every entry plus an appended C</.> will be C<stat>'ed, 941entry plus an appended C</.> will be C<stat>'ed, likely directories first,
704likely directories first. If that succeeds, it assumes that the entry 942in order of their inode numbers. If that succeeds, it assumes that the
705is a directory or a symlink to directory (which will be checked 943entry is a directory or a symlink to directory (which will be checked
706seperately). This is often faster than stat'ing the entry itself because 944separately). This is often faster than stat'ing the entry itself because
707filesystems might detect the type of the entry without reading the inode 945filesystems might detect the type of the entry without reading the inode
708data (e.g. ext2fs filetype feature). 946data (e.g. ext2fs filetype feature), even on systems that cannot return
947the filetype information on readdir.
709 948
710If the known number of directories (link count - 2) has been reached, the 949If the known number of directories (link count - 2) has been reached, the
711rest of the entries is assumed to be non-directories. 950rest of the entries is assumed to be non-directories.
712 951
713This only works with certainty on POSIX (= UNIX) filesystems, which 952This only works with certainty on POSIX (= UNIX) filesystems, which
… …
735 my $now = time; 974 my $now = time;
736 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 975 my $hash1 = join ":", (stat _)[0,1,3,7,9];
737 976
738 # read the directory entries 977 # read the directory entries
739 aioreq_pri $pri; 978 aioreq_pri $pri;
740 add $grp aio_readdir $path, sub { 979 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
741 my $entries = shift 980 my $entries = shift
742 or return $grp->result (); 981 or return $grp->result ();
743 982
744 # stat the dir another time 983 # stat the dir another time
745 aioreq_pri $pri; 984 aioreq_pri $pri;
… …
751 # take the slow route if anything looks fishy 990 # take the slow route if anything looks fishy
752 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 991 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
753 $ndirs = -1; 992 $ndirs = -1;
754 } else { 993 } else {
755 # if nlink == 2, we are finished 994 # if nlink == 2, we are finished
756 # on non-posix-fs's, we rely on nlink < 2 995 # for non-posix-fs's, we rely on nlink < 2
757 $ndirs = (stat _)[3] - 2 996 $ndirs = (stat _)[3] - 2
758 or return $grp->result ([], $entries); 997 or return $grp->result ([], $entries);
759 } 998 }
760 999
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); 1000 my (@dirs, @nondirs);
769 1001
770 my $statgrp = add $grp aio_group sub { 1002 my $statgrp = add $grp aio_group sub {
771 $grp->result (\@dirs, \@nondirs); 1003 $grp->result (\@dirs, \@nondirs);
772 }; 1004 };
773 1005
774 limit $statgrp $maxreq; 1006 limit $statgrp $maxreq;
775 feed $statgrp sub { 1007 feed $statgrp sub {
776 return unless @$entries; 1008 return unless @$entries;
777 my $entry = pop @$entries; 1009 my $entry = shift @$entries;
778 1010
779 aioreq_pri $pri; 1011 aioreq_pri $pri;
780 add $statgrp aio_stat "$path/$entry/.", sub { 1012 add $statgrp aio_stat "$path/$entry/.", sub {
781 if ($_[0] < 0) { 1013 if ($_[0] < 0) {
782 push @nondirs, $entry; 1014 push @nondirs, $entry;
… …
855callback with the fdatasync result code. 1087callback with the fdatasync result code.
856 1088
857If this call isn't available because your OS lacks it or it couldn't be 1089If 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. 1090detected, it will be emulated by calling C<fsync> instead.
859 1091
1092=item aio_syncfs $fh, $callback->($status)
1093
1094Asynchronously call the syncfs syscall to sync the filesystem associated
1095to the given filehandle and call the callback with the syncfs result
1096code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1097errno to C<ENOSYS> nevertheless.
1098
1099=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1100
1101Sync the data portion of the file specified by C<$offset> and C<$length>
1102to disk (but NOT the metadata), by calling the Linux-specific
1103sync_file_range call. If sync_file_range is not available or it returns
1104ENOSYS, then fdatasync or fsync is being substituted.
1105
1106C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109manpage for details.
1110
860=item aio_pathsync $path, $callback->($status) 1111=item aio_pathsync $path, $callback->($status)
861 1112
862This request tries to open, fsync and close the given path. This is a 1113This request tries to open, fsync and close the given path. This is a
863composite request intended tosync directories after directory operations 1114composite request intended to sync directories after directory operations
864(E.g. rename). This might not work on all operating systems or have any 1115(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 1116specific effect, but usually it makes sure that directory changes get
866written to disc. It works for anything that can be opened for read-only, 1117written to disc. It works for anything that can be opened for read-only,
867not just directories. 1118not just directories.
1119
1120Future versions of this function might fall back to other methods when
1121C<fsync> on the directory fails (such as calling C<sync>).
868 1122
869Passes C<0> when everything went ok, and C<-1> on error. 1123Passes C<0> when everything went ok, and C<-1> on error.
870 1124
871=cut 1125=cut
872 1126
… …
893 }; 1147 };
894 1148
895 $grp 1149 $grp
896} 1150}
897 1151
1152=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1153
1154This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1155scalars (see the C<IO::AIO::mmap> function, although it also works on data
1156scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1157scalar must only be modified in-place while an aio operation is pending on
1158it).
1159
1160It calls the C<msync> function of your OS, if available, with the memory
1161area starting at C<$offset> in the string and ending C<$length> bytes
1162later. If C<$length> is negative, counts from the end, and if C<$length>
1163is C<undef>, then it goes till the end of the string. The flags can be
1164a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1165C<IO::AIO::MS_SYNC>.
1166
1167=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1168
1169This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170scalars.
1171
1172It touches (reads or writes) all memory pages in the specified
1173range inside the scalar. All caveats and parameters are the same
1174as for C<aio_msync>, above, except for flags, which must be either
1175C<0> (which reads all pages and ensures they are instantiated) or
1176C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1177writing an octet from it, which dirties the page).
1178
1179=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1180
1181This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1182scalars.
1183
1184It reads in all the pages of the underlying storage into memory (if any)
1185and locks them, so they are not getting swapped/paged out or removed.
1186
1187If C<$length> is undefined, then the scalar will be locked till the end.
1188
1189On systems that do not implement C<mlock>, this function returns C<-1>
1190and sets errno to C<ENOSYS>.
1191
1192Note that the corresponding C<munlock> is synchronous and is
1193documented under L<MISCELLANEOUS FUNCTIONS>.
1194
1195Example: open a file, mmap and mlock it - both will be undone when
1196C<$data> gets destroyed.
1197
1198 open my $fh, "<", $path or die "$path: $!";
1199 my $data;
1200 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1201 aio_mlock $data; # mlock in background
1202
1203=item aio_mlockall $flags, $callback->($status)
1204
1205Calls the C<mlockall> function with the given C<$flags> (a combination of
1206C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1207
1208On systems that do not implement C<mlockall>, this function returns C<-1>
1209and sets errno to C<ENOSYS>.
1210
1211Note that the corresponding C<munlockall> is synchronous and is
1212documented under L<MISCELLANEOUS FUNCTIONS>.
1213
1214Example: asynchronously lock all current and future pages into memory.
1215
1216 aio_mlockall IO::AIO::MCL_FUTURE;
1217
898=item aio_group $callback->(...) 1218=item aio_group $callback->(...)
899 1219
900This is a very special aio request: Instead of doing something, it is a 1220This 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 1221container for other aio requests, which is useful if you want to bundle
902many requests into a single, composite, request with a definite callback 1222many requests into a single, composite, request with a definite callback
… …
951=item cancel $req 1271=item cancel $req
952 1272
953Cancels the request, if possible. Has the effect of skipping execution 1273Cancels the request, if possible. Has the effect of skipping execution
954when entering the B<execute> state and skipping calling the callback when 1274when entering the B<execute> state and skipping calling the callback when
955entering the the B<result> state, but will leave the request otherwise 1275entering the the B<result> state, but will leave the request otherwise
956untouched. That means that requests that currently execute will not be 1276untouched (with the exception of readdir). That means that requests that
957stopped and resources held by the request will not be freed prematurely. 1277currently execute will not be stopped and resources held by the request
1278will not be freed prematurely.
958 1279
959=item cb $req $callback->(...) 1280=item cb $req $callback->(...)
960 1281
961Replace (or simply set) the callback registered to the request. 1282Replace (or simply set) the callback registered to the request.
962 1283
… …
1013Their lifetime, simplified, looks like this: when they are empty, they 1334Their lifetime, simplified, looks like this: when they are empty, they
1014will finish very quickly. If they contain only requests that are in the 1335will finish very quickly. If they contain only requests that are in the
1015C<done> state, they will also finish. Otherwise they will continue to 1336C<done> state, they will also finish. Otherwise they will continue to
1016exist. 1337exist.
1017 1338
1018That means after creating a group you have some time to add requests. And 1339That 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 1340(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 1341the C<poll_cb>). And in the callbacks of those requests, you can add
1021itself finish. 1342further requests to the group. And only when all those requests have
1343finished will the the group itself finish.
1022 1344
1023=over 4 1345=over 4
1024 1346
1025=item add $grp ... 1347=item add $grp ...
1026 1348
… …
1034 1356
1035=item $grp->cancel_subs 1357=item $grp->cancel_subs
1036 1358
1037Cancel all subrequests and clears any feeder, but not the group request 1359Cancel 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. 1360itself. Useful when you queued a lot of events but got a result early.
1361
1362The group request will finish normally (you cannot add requests to the
1363group).
1039 1364
1040=item $grp->result (...) 1365=item $grp->result (...)
1041 1366
1042Set the result value(s) that will be passed to the group callback when all 1367Set 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 1368subrequests have finished and set the groups errno to the current value
… …
1059=item feed $grp $callback->($grp) 1384=item feed $grp $callback->($grp)
1060 1385
1061Sets a feeder/generator on this group: every group can have an attached 1386Sets a feeder/generator on this group: every group can have an attached
1062generator that generates requests if idle. The idea behind this is that, 1387generator 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, 1388although you could just queue as many requests as you want in a group,
1064this might starve other requests for a potentially long time. For 1389this might starve other requests for a potentially long time. For example,
1065example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1390C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1066requests, delaying any later requests for a long time. 1391delaying any later requests for a long time.
1067 1392
1068To avoid this, and allow incremental generation of requests, you can 1393To avoid this, and allow incremental generation of requests, you can
1069instead a group and set a feeder on it that generates those requests. The 1394instead 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>, 1395feed 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 1396below) requests active in the group itself and is expected to queue more
… …
1075not impose any limits). 1400not impose any limits).
1076 1401
1077If the feed does not queue more requests when called, it will be 1402If the feed does not queue more requests when called, it will be
1078automatically removed from the group. 1403automatically removed from the group.
1079 1404
1080If the feed limit is C<0>, it will be set to C<2> automatically. 1405If the feed limit is C<0> when this method is called, it will be set to
1406C<2> automatically.
1081 1407
1082Example: 1408Example:
1083 1409
1084 # stat all files in @files, but only ever use four aio requests concurrently: 1410 # stat all files in @files, but only ever use four aio requests concurrently:
1085 1411
… …
1097Sets the feeder limit for the group: The feeder will be called whenever 1423Sets the feeder limit for the group: The feeder will be called whenever
1098the group contains less than this many requests. 1424the group contains less than this many requests.
1099 1425
1100Setting the limit to C<0> will pause the feeding process. 1426Setting the limit to C<0> will pause the feeding process.
1101 1427
1428The default value for the limit is C<0>, but note that setting a feeder
1429automatically bumps it up to C<2>.
1430
1102=back 1431=back
1103 1432
1104=head2 SUPPORT FUNCTIONS 1433=head2 SUPPORT FUNCTIONS
1105 1434
1106=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1435=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1108=over 4 1437=over 4
1109 1438
1110=item $fileno = IO::AIO::poll_fileno 1439=item $fileno = IO::AIO::poll_fileno
1111 1440
1112Return the I<request result pipe file descriptor>. This filehandle must be 1441Return the I<request result pipe file descriptor>. This filehandle must be
1113polled for reading by some mechanism outside this module (e.g. Event or 1442polled 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 1443select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1115to call C<poll_cb> to check the results. 1444you have to call C<poll_cb> to check the results.
1116 1445
1117See C<poll_cb> for an example. 1446See C<poll_cb> for an example.
1118 1447
1119=item IO::AIO::poll_cb 1448=item IO::AIO::poll_cb
1120 1449
1121Process some outstanding events on the result pipe. You have to call this 1450Process some outstanding events on the result pipe. You have to call
1122regularly. Returns the number of events processed. Returns immediately 1451this regularly. Returns C<0> if all events could be processed (or there
1123when no events are outstanding. The amount of events processed depends on 1452were 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>. 1453reason. Returns immediately when no events are outstanding. The amount of
1454events processed depends on the settings of C<IO::AIO::max_poll_req> and
1455C<IO::AIO::max_poll_time>.
1125 1456
1126If not all requests were processed for whatever reason, the filehandle 1457If not all requests were processed for whatever reason, the filehandle
1127will still be ready when C<poll_cb> returns. 1458will still be ready when C<poll_cb> returns, so normally you don't have to
1459do anything special to have it called later.
1460
1461Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1462ready, it can be beneficial to call this function from loops which submit
1463a lot of requests, to make sure the results get processed when they become
1464available and not just when the loop is finished and the event loop takes
1465over again. This function returns very fast when there are no outstanding
1466requests.
1128 1467
1129Example: Install an Event watcher that automatically calls 1468Example: Install an Event watcher that automatically calls
1130IO::AIO::poll_cb with high priority: 1469IO::AIO::poll_cb with high priority (more examples can be found in the
1470SYNOPSIS section, at the top of this document):
1131 1471
1132 Event->io (fd => IO::AIO::poll_fileno, 1472 Event->io (fd => IO::AIO::poll_fileno,
1133 poll => 'r', async => 1, 1473 poll => 'r', async => 1,
1134 cb => \&IO::AIO::poll_cb); 1474 cb => \&IO::AIO::poll_cb);
1475
1476=item IO::AIO::poll_wait
1477
1478If there are any outstanding requests and none of them in the result
1479phase, wait till the result filehandle becomes ready for reading (simply
1480does a C<select> on the filehandle. This is useful if you want to
1481synchronously wait for some requests to finish).
1482
1483See C<nreqs> for an example.
1484
1485=item IO::AIO::poll
1486
1487Waits until some requests have been handled.
1488
1489Returns the number of requests processed, but is otherwise strictly
1490equivalent to:
1491
1492 IO::AIO::poll_wait, IO::AIO::poll_cb
1493
1494=item IO::AIO::flush
1495
1496Wait till all outstanding AIO requests have been handled.
1497
1498Strictly equivalent to:
1499
1500 IO::AIO::poll_wait, IO::AIO::poll_cb
1501 while IO::AIO::nreqs;
1135 1502
1136=item IO::AIO::max_poll_reqs $nreqs 1503=item IO::AIO::max_poll_reqs $nreqs
1137 1504
1138=item IO::AIO::max_poll_time $seconds 1505=item IO::AIO::max_poll_time $seconds
1139 1506
… …
1164 # use a low priority so other tasks have priority 1531 # use a low priority so other tasks have priority
1165 Event->io (fd => IO::AIO::poll_fileno, 1532 Event->io (fd => IO::AIO::poll_fileno,
1166 poll => 'r', nice => 1, 1533 poll => 'r', nice => 1,
1167 cb => &IO::AIO::poll_cb); 1534 cb => &IO::AIO::poll_cb);
1168 1535
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 1536=back
1197 1537
1198=head3 CONTROLLING THE NUMBER OF THREADS 1538=head3 CONTROLLING THE NUMBER OF THREADS
1199 1539
1200=over 1540=over
… …
1233 1573
1234Under normal circumstances you don't need to call this function. 1574Under normal circumstances you don't need to call this function.
1235 1575
1236=item IO::AIO::max_idle $nthreads 1576=item IO::AIO::max_idle $nthreads
1237 1577
1238Limit the number of threads (default: 4) that are allowed to idle (i.e., 1578Limit the number of threads (default: 4) that are allowed to idle
1239threads that did not get a request to process within 10 seconds). That 1579(i.e., threads that did not get a request to process within the idle
1240means if a thread becomes idle while C<$nthreads> other threads are also 1580timeout (default: 10 seconds). That means if a thread becomes idle while
1241idle, it will free its resources and exit. 1581C<$nthreads> other threads are also idle, it will free its resources and
1582exit.
1242 1583
1243This is useful when you allow a large number of threads (e.g. 100 or 1000) 1584This 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 1585to allow for extremely high load situations, but want to free resources
1245under normal circumstances (1000 threads can easily consume 30MB of RAM). 1586under normal circumstances (1000 threads can easily consume 30MB of RAM).
1246 1587
1247The default is probably ok in most situations, especially if thread 1588The default is probably ok in most situations, especially if thread
1248creation is fast. If thread creation is very slow on your system you might 1589creation is fast. If thread creation is very slow on your system you might
1249want to use larger values. 1590want to use larger values.
1250 1591
1592=item IO::AIO::idle_timeout $seconds
1593
1594Sets the minimum idle timeout (default 10) after which worker threads are
1595allowed to exit. SEe C<IO::AIO::max_idle>.
1596
1251=item IO::AIO::max_outstanding $maxreqs 1597=item IO::AIO::max_outstanding $maxreqs
1598
1599Sets the maximum number of outstanding requests to C<$nreqs>. If
1600you do queue up more than this number of requests, the next call to
1601C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1602C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1603longer exceeded.
1604
1605In other words, this setting does not enforce a queue limit, but can be
1606used to make poll functions block if the limit is exceeded.
1252 1607
1253This is a very bad function to use in interactive programs because it 1608This 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 1609blocks, and a bad way to reduce concurrency because it is inexact: Better
1255use an C<aio_group> together with a feed callback. 1610use an C<aio_group> together with a feed callback.
1256 1611
1257Sets the maximum number of outstanding requests to C<$nreqs>. If you 1612It'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 1613a 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 1614
1262The default value is very large, so there is no practical limit on the 1615 IO::AIO::max_outstanding 32;
1263number of outstanding requests.
1264 1616
1265You can still queue as many requests as you want. Therefore, 1617 for my $path (...) {
1266C<max_outstanding> is mainly useful in simple scripts (with low values) or 1618 aio_stat $path , ...;
1267as a stop gap to shield against fatal memory overflow (with large values). 1619 IO::AIO::poll_cb;
1620 }
1621
1622 IO::AIO::flush;
1623
1624The call to C<poll_cb> inside the loop will normally return instantly, but
1625as soon as more thna C<32> reqeusts are in-flight, it will block until
1626some requests have been handled. This keeps the loop from pushing a large
1627number of C<aio_stat> requests onto the queue.
1628
1629The default value for C<max_outstanding> is very large, so there is no
1630practical limit on the number of outstanding requests.
1268 1631
1269=back 1632=back
1270 1633
1271=head3 STATISTICAL INFORMATION 1634=head3 STATISTICAL INFORMATION
1272 1635
… …
1292Returns the number of requests currently in the pending state (executed, 1655Returns the number of requests currently in the pending state (executed,
1293but not yet processed by poll_cb). 1656but not yet processed by poll_cb).
1294 1657
1295=back 1658=back
1296 1659
1660=head3 MISCELLANEOUS FUNCTIONS
1661
1662IO::AIO implements some functions that might be useful, but are not
1663asynchronous.
1664
1665=over 4
1666
1667=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1668
1669Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1670but is blocking (this makes most sense if you know the input data is
1671likely cached already and the output filehandle is set to non-blocking
1672operations).
1673
1674Returns the number of bytes copied, or C<-1> on error.
1675
1676=item IO::AIO::fadvise $fh, $offset, $len, $advice
1677
1678Simply calls the C<posix_fadvise> function (see its
1679manpage for details). The following advice constants are
1680available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1681C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1682C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1683
1684On systems that do not implement C<posix_fadvise>, this function returns
1685ENOSYS, otherwise the return value of C<posix_fadvise>.
1686
1687=item IO::AIO::madvise $scalar, $offset, $len, $advice
1688
1689Simply calls the C<posix_madvise> function (see its
1690manpage for details). The following advice constants are
1691available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1692C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1693
1694On systems that do not implement C<posix_madvise>, this function returns
1695ENOSYS, otherwise the return value of C<posix_madvise>.
1696
1697=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1698
1699Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1700$scalar (see its manpage for details). The following protect
1701constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1702C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1703
1704On systems that do not implement C<mprotect>, this function returns
1705ENOSYS, otherwise the return value of C<mprotect>.
1706
1707=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708
1709Memory-maps a file (or anonymous memory range) and attaches it to the
1710given C<$scalar>, which will act like a string scalar.
1711
1712The only operations allowed on the scalar are C<substr>/C<vec> that don't
1713change the string length, and most read-only operations such as copying it
1714or searching it with regexes and so on.
1715
1716Anything else is unsafe and will, at best, result in memory leaks.
1717
1718The memory map associated with the C<$scalar> is automatically removed
1719when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1720C<IO::AIO::munmap> functions are called.
1721
1722This calls the C<mmap>(2) function internally. See your system's manual
1723page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1724
1725The C<$length> must be larger than zero and smaller than the actual
1726filesize.
1727
1728C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1729C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1730
1731C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1732C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1733not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1734(which is set to C<MAP_ANON> if your system only provides this
1735constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1736C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1737C<IO::AIO::MAP_NONBLOCK>
1738
1739If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1740
1741C<$offset> is the offset from the start of the file - it generally must be
1742a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1743
1744Example:
1745
1746 use Digest::MD5;
1747 use IO::AIO;
1748
1749 open my $fh, "<verybigfile"
1750 or die "$!";
1751
1752 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1753 or die "verybigfile: $!";
1754
1755 my $fast_md5 = md5 $data;
1756
1757=item IO::AIO::munmap $scalar
1758
1759Removes a previous mmap and undefines the C<$scalar>.
1760
1761=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1762
1763Calls the C<munlock> function, undoing the effects of a previous
1764C<aio_mlock> call (see its description for details).
1765
1766=item IO::AIO::munlockall
1767
1768Calls the C<munlockall> function.
1769
1770On systems that do not implement C<munlockall>, this function returns
1771ENOSYS, otherwise the return value of C<munlockall>.
1772
1773=back
1774
1297=cut 1775=cut
1298 1776
1299min_parallel 8; 1777min_parallel 8;
1300 1778
1301END { flush } 1779END { flush }
1302 1780
13031; 17811;
1304 1782
1783=head1 EVENT LOOP INTEGRATION
1784
1785It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1786automatically into many event loops:
1787
1788 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1789 use AnyEvent::AIO;
1790
1791You can also integrate IO::AIO manually into many event loops, here are
1792some examples of how to do this:
1793
1794 # EV integration
1795 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1796
1797 # Event integration
1798 Event->io (fd => IO::AIO::poll_fileno,
1799 poll => 'r',
1800 cb => \&IO::AIO::poll_cb);
1801
1802 # Glib/Gtk2 integration
1803 add_watch Glib::IO IO::AIO::poll_fileno,
1804 in => sub { IO::AIO::poll_cb; 1 };
1805
1806 # Tk integration
1807 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1808 readable => \&IO::AIO::poll_cb);
1809
1810 # Danga::Socket integration
1811 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1812 \&IO::AIO::poll_cb);
1813
1305=head2 FORK BEHAVIOUR 1814=head2 FORK BEHAVIOUR
1306 1815
1307This module should do "the right thing" when the process using it forks: 1816Usage of pthreads in a program changes the semantics of fork
1817considerably. Specifically, only async-safe functions can be called after
1818fork. Perl doesn't know about this, so in general, you cannot call fork
1819with defined behaviour in perl if pthreads are involved. IO::AIO uses
1820pthreads, so this applies, but many other extensions and (for inexplicable
1821reasons) perl itself often is linked against pthreads, so this limitation
1822applies to quite a lot of perls.
1308 1823
1309Before the fork, IO::AIO enters a quiescent state where no requests 1824This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1310can be added in other threads and no results will be processed. After 1825only works in the process that loaded it. Forking is fully supported, but
1311the fork the parent simply leaves the quiescent state and continues 1826using IO::AIO in the child is not.
1312request/result processing, while the child frees the request/result queue
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 1827
1317In short: the parent will, after a short pause, continue as if fork had 1828You might get around by not I<using> IO::AIO before (or after)
1318not been called, while the child will act as if IO::AIO has not been used 1829forking. You could also try to call the L<IO::AIO::reinit> function in the
1319yet. 1830child:
1831
1832=over 4
1833
1834=item IO::AIO::reinit
1835
1836Abandons all current requests and I/O threads and simply reinitialises all
1837data structures. This is not an operation supported by any standards, but
1838happens to work on GNU/Linux and some newer BSD systems.
1839
1840The only reasonable use for this function is to call it after forking, if
1841C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
1842the process will result in undefined behaviour. Calling it at any time
1843will also result in any undefined (by POSIX) behaviour.
1844
1845=back
1320 1846
1321=head2 MEMORY USAGE 1847=head2 MEMORY USAGE
1322 1848
1323Per-request usage: 1849Per-request usage:
1324 1850

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