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Revision 1.131 by root, Tue Jul 15 10:42:26 2008 UTC vs.
Revision 1.202 by root, Tue Jul 5 14:02:15 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 = '3.06'; 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 (Same as
653L<Cwd::realpath>).
654
655This request can be used to get the absolute path of the current working
656directory by passing it a path of F<.> (a single dot).
657
658
507=item aio_rename $srcpath, $dstpath, $callback->($status) 659=item aio_rename $srcpath, $dstpath, $callback->($status)
508 660
509Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 661Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
510rename(2) and call the callback with the result code. 662rename(2) and call the callback with the result code.
511 663
… …
527 679
528Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 680Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
529directory (i.e. opendir + readdir + closedir). The entries will not be 681directory (i.e. opendir + readdir + closedir). The entries will not be
530sorted, and will B<NOT> include the C<.> and C<..> entries. 682sorted, and will B<NOT> include the C<.> and C<..> entries.
531 683
532The callback a single argument which is either C<undef> or an array-ref 684The callback is passed a single argument which is either C<undef> or an
533with the filenames. 685array-ref with the filenames.
686
687
688=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
689
690Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
691behaviour and output format. In case of an error, C<$entries> will be
692C<undef>.
693
694The flags are a combination of the following constants, ORed together (the
695flags will also be passed to the callback, possibly modified):
696
697=over 4
698
699=item IO::AIO::READDIR_DENTS
700
701When this flag is off, then the callback gets an arrayref consisting of
702names only (as with C<aio_readdir>), otherwise it gets an arrayref with
703C<[$name, $type, $inode]> arrayrefs, each describing a single directory
704entry in more detail.
705
706C<$name> is the name of the entry.
707
708C<$type> is one of the C<IO::AIO::DT_xxx> constants:
709
710C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
711C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
712C<IO::AIO::DT_WHT>.
713
714C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
715know, you have to run stat yourself. Also, for speed reasons, the C<$type>
716scalars are read-only: you can not modify them.
717
718C<$inode> is the inode number (which might not be exact on systems with 64
719bit inode numbers and 32 bit perls). This field has unspecified content on
720systems that do not deliver the inode information.
721
722=item IO::AIO::READDIR_DIRS_FIRST
723
724When this flag is set, then the names will be returned in an order where
725likely directories come first, in optimal stat order. This is useful when
726you need to quickly find directories, or you want to find all directories
727while avoiding to stat() each entry.
728
729If the system returns type information in readdir, then this is used
730to find directories directly. Otherwise, likely directories are names
731beginning with ".", or otherwise names with no dots, of which names with
732short names are tried first.
733
734=item IO::AIO::READDIR_STAT_ORDER
735
736When this flag is set, then the names will be returned in an order
737suitable for stat()'ing each one. That is, when you plan to stat()
738all files in the given directory, then the returned order will likely
739be fastest.
740
741If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
742the likely dirs come first, resulting in a less optimal stat order.
743
744=item IO::AIO::READDIR_FOUND_UNKNOWN
745
746This flag should not be set when calling C<aio_readdirx>. Instead, it
747is being set by C<aio_readdirx>, when any of the C<$type>'s found were
748C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
749C<$type>'s are known, which can be used to speed up some algorithms.
750
751=back
534 752
535 753
536=item aio_load $path, $data, $callback->($status) 754=item aio_load $path, $data, $callback->($status)
537 755
538This is a composite request that tries to fully load the given file into 756This is a composite request that tries to fully load the given file into
… …
563 781
564=item aio_copy $srcpath, $dstpath, $callback->($status) 782=item aio_copy $srcpath, $dstpath, $callback->($status)
565 783
566Try to copy the I<file> (directories not supported as either source or 784Try to copy the I<file> (directories not supported as either source or
567destination) from C<$srcpath> to C<$dstpath> and call the callback with 785destination) from C<$srcpath> to C<$dstpath> and call the callback with
568the C<0> (error) or C<-1> ok. 786a status of C<0> (ok) or C<-1> (error, see C<$!>).
569 787
570This is a composite request that it creates the destination file with 788This is a composite request that creates the destination file with
571mode 0200 and copies the contents of the source file into it using 789mode 0200 and copies the contents of the source file into it using
572C<aio_sendfile>, followed by restoring atime, mtime, access mode and 790C<aio_sendfile>, followed by restoring atime, mtime, access mode and
573uid/gid, in that order. 791uid/gid, in that order.
574 792
575If an error occurs, the partial destination file will be unlinked, if 793If an error occurs, the partial destination file will be unlinked, if
… …
585 my $grp = aio_group $cb; 803 my $grp = aio_group $cb;
586 804
587 aioreq_pri $pri; 805 aioreq_pri $pri;
588 add $grp aio_open $src, O_RDONLY, 0, sub { 806 add $grp aio_open $src, O_RDONLY, 0, sub {
589 if (my $src_fh = $_[0]) { 807 if (my $src_fh = $_[0]) {
590 my @stat = stat $src_fh; 808 my @stat = stat $src_fh; # hmm, might block over nfs?
591 809
592 aioreq_pri $pri; 810 aioreq_pri $pri;
593 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 811 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
594 if (my $dst_fh = $_[0]) { 812 if (my $dst_fh = $_[0]) {
595 aioreq_pri $pri; 813 aioreq_pri $pri;
596 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 814 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
597 if ($_[0] == $stat[7]) { 815 if ($_[0] == $stat[7]) {
598 $grp->result (0); 816 $grp->result (0);
599 close $src_fh; 817 close $src_fh;
600 818
601 # those should not normally block. should. should. 819 my $ch = sub {
602 utime $stat[8], $stat[9], $dst; 820 aioreq_pri $pri;
603 chmod $stat[2] & 07777, $dst_fh; 821 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
604 chown $stat[4], $stat[5], $dst_fh; 822 aioreq_pri $pri;
823 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
824 aioreq_pri $pri;
825 add $grp aio_close $dst_fh;
826 }
827 };
828 };
605 829
606 aioreq_pri $pri; 830 aioreq_pri $pri;
607 add $grp aio_close $dst_fh; 831 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
832 if ($_[0] < 0 && $! == ENOSYS) {
833 aioreq_pri $pri;
834 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
835 } else {
836 $ch->();
837 }
838 };
608 } else { 839 } else {
609 $grp->result (-1); 840 $grp->result (-1);
610 close $src_fh; 841 close $src_fh;
611 close $dst_fh; 842 close $dst_fh;
612 843
… …
629 860
630=item aio_move $srcpath, $dstpath, $callback->($status) 861=item aio_move $srcpath, $dstpath, $callback->($status)
631 862
632Try to move the I<file> (directories not supported as either source or 863Try to move the I<file> (directories not supported as either source or
633destination) from C<$srcpath> to C<$dstpath> and call the callback with 864destination) from C<$srcpath> to C<$dstpath> and call the callback with
634the C<0> (error) or C<-1> ok. 865a status of C<0> (ok) or C<-1> (error, see C<$!>).
635 866
636This is a composite request that tries to rename(2) the file first. If 867This is a composite request that tries to rename(2) the file first; if
637rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 868rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
638that is successful, unlinking the C<$srcpath>. 869that is successful, unlinks the C<$srcpath>.
639 870
640=cut 871=cut
641 872
642sub aio_move($$;$) { 873sub aio_move($$;$) {
643 my ($src, $dst, $cb) = @_; 874 my ($src, $dst, $cb) = @_;
… …
650 if ($_[0] && $! == EXDEV) { 881 if ($_[0] && $! == EXDEV) {
651 aioreq_pri $pri; 882 aioreq_pri $pri;
652 add $grp aio_copy $src, $dst, sub { 883 add $grp aio_copy $src, $dst, sub {
653 $grp->result ($_[0]); 884 $grp->result ($_[0]);
654 885
655 if (!$_[0]) { 886 unless ($_[0]) {
656 aioreq_pri $pri; 887 aioreq_pri $pri;
657 add $grp aio_unlink $src; 888 add $grp aio_unlink $src;
658 } 889 }
659 }; 890 };
660 } else { 891 } else {
… …
690 921
691Implementation notes. 922Implementation notes.
692 923
693The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 924The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
694 925
926If readdir returns file type information, then this is used directly to
927find directories.
928
695After reading the directory, the modification time, size etc. of the 929Otherwise, after reading the directory, the modification time, size etc.
696directory before and after the readdir is checked, and if they match (and 930of 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 931match (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 932how many entries are directories (if >= 2). Otherwise, no knowledge of the
699of subdirectories will be assumed. 933number of subdirectories will be assumed.
700 934
701Then entries will be sorted into likely directories (everything without 935Then entries will be sorted into likely directories a non-initial dot
702a non-initial dot currently) and likely non-directories (everything 936currently) and likely non-directories (see C<aio_readdirx>). Then every
703else). Then every entry plus an appended C</.> will be C<stat>'ed, 937entry plus an appended C</.> will be C<stat>'ed, likely directories first,
704likely directories first. If that succeeds, it assumes that the entry 938in order of their inode numbers. If that succeeds, it assumes that the
705is a directory or a symlink to directory (which will be checked 939entry is a directory or a symlink to directory (which will be checked
706seperately). This is often faster than stat'ing the entry itself because 940seperately). This is often faster than stat'ing the entry itself because
707filesystems might detect the type of the entry without reading the inode 941filesystems might detect the type of the entry without reading the inode
708data (e.g. ext2fs filetype feature). 942data (e.g. ext2fs filetype feature), even on systems that cannot return
943the filetype information on readdir.
709 944
710If the known number of directories (link count - 2) has been reached, the 945If the known number of directories (link count - 2) has been reached, the
711rest of the entries is assumed to be non-directories. 946rest of the entries is assumed to be non-directories.
712 947
713This only works with certainty on POSIX (= UNIX) filesystems, which 948This only works with certainty on POSIX (= UNIX) filesystems, which
… …
735 my $now = time; 970 my $now = time;
736 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 971 my $hash1 = join ":", (stat _)[0,1,3,7,9];
737 972
738 # read the directory entries 973 # read the directory entries
739 aioreq_pri $pri; 974 aioreq_pri $pri;
740 add $grp aio_readdir $path, sub { 975 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
741 my $entries = shift 976 my $entries = shift
742 or return $grp->result (); 977 or return $grp->result ();
743 978
744 # stat the dir another time 979 # stat the dir another time
745 aioreq_pri $pri; 980 aioreq_pri $pri;
… …
751 # take the slow route if anything looks fishy 986 # take the slow route if anything looks fishy
752 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 987 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
753 $ndirs = -1; 988 $ndirs = -1;
754 } else { 989 } else {
755 # if nlink == 2, we are finished 990 # if nlink == 2, we are finished
756 # on non-posix-fs's, we rely on nlink < 2 991 # for non-posix-fs's, we rely on nlink < 2
757 $ndirs = (stat _)[3] - 2 992 $ndirs = (stat _)[3] - 2
758 or return $grp->result ([], $entries); 993 or return $grp->result ([], $entries);
759 } 994 }
760 995
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); 996 my (@dirs, @nondirs);
769 997
770 my $statgrp = add $grp aio_group sub { 998 my $statgrp = add $grp aio_group sub {
771 $grp->result (\@dirs, \@nondirs); 999 $grp->result (\@dirs, \@nondirs);
772 }; 1000 };
773 1001
774 limit $statgrp $maxreq; 1002 limit $statgrp $maxreq;
775 feed $statgrp sub { 1003 feed $statgrp sub {
776 return unless @$entries; 1004 return unless @$entries;
777 my $entry = pop @$entries; 1005 my $entry = shift @$entries;
778 1006
779 aioreq_pri $pri; 1007 aioreq_pri $pri;
780 add $statgrp aio_stat "$path/$entry/.", sub { 1008 add $statgrp aio_stat "$path/$entry/.", sub {
781 if ($_[0] < 0) { 1009 if ($_[0] < 0) {
782 push @nondirs, $entry; 1010 push @nondirs, $entry;
… …
855callback with the fdatasync result code. 1083callback with the fdatasync result code.
856 1084
857If this call isn't available because your OS lacks it or it couldn't be 1085If 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. 1086detected, it will be emulated by calling C<fsync> instead.
859 1087
1088=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1089
1090Sync the data portion of the file specified by C<$offset> and C<$length>
1091to disk (but NOT the metadata), by calling the Linux-specific
1092sync_file_range call. If sync_file_range is not available or it returns
1093ENOSYS, then fdatasync or fsync is being substituted.
1094
1095C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1096C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1097C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1098manpage for details.
1099
860=item aio_pathsync $path, $callback->($status) 1100=item aio_pathsync $path, $callback->($status)
861 1101
862This request tries to open, fsync and close the given path. This is a 1102This request tries to open, fsync and close the given path. This is a
863composite request intended tosync directories after directory operations 1103composite request intended to sync directories after directory operations
864(E.g. rename). This might not work on all operating systems or have any 1104(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 1105specific effect, but usually it makes sure that directory changes get
866written to disc. It works for anything that can be opened for read-only, 1106written to disc. It works for anything that can be opened for read-only,
867not just directories. 1107not just directories.
1108
1109Future versions of this function might fall back to other methods when
1110C<fsync> on the directory fails (such as calling C<sync>).
868 1111
869Passes C<0> when everything went ok, and C<-1> on error. 1112Passes C<0> when everything went ok, and C<-1> on error.
870 1113
871=cut 1114=cut
872 1115
… …
893 }; 1136 };
894 1137
895 $grp 1138 $grp
896} 1139}
897 1140
1141=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1142
1143This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1144scalars (see the C<IO::AIO::mmap> function, although it also works on data
1145scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1146scalar must only be modified in-place while an aio operation is pending on
1147it).
1148
1149It calls the C<msync> function of your OS, if available, with the memory
1150area starting at C<$offset> in the string and ending C<$length> bytes
1151later. If C<$length> is negative, counts from the end, and if C<$length>
1152is C<undef>, then it goes till the end of the string. The flags can be
1153a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1154C<IO::AIO::MS_SYNC>.
1155
1156=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1157
1158This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1159scalars.
1160
1161It touches (reads or writes) all memory pages in the specified
1162range inside the scalar. All caveats and parameters are the same
1163as for C<aio_msync>, above, except for flags, which must be either
1164C<0> (which reads all pages and ensures they are instantiated) or
1165C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1166writing an octet from it, which dirties the page).
1167
1168=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1169
1170This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1171scalars.
1172
1173It reads in all the pages of the underlying storage into memory (if any)
1174and locks them, so they are not getting swapped/paged out or removed.
1175
1176If C<$length> is undefined, then the scalar will be locked till the end.
1177
1178On systems that do not implement C<mlock>, this function returns C<-1>
1179and sets errno to C<ENOSYS>.
1180
1181Note that the corresponding C<munlock> is synchronous and is
1182documented under L<MISCELLANEOUS FUNCTIONS>.
1183
1184Example: open a file, mmap and mlock it - both will be undone when
1185C<$data> gets destroyed.
1186
1187 open my $fh, "<", $path or die "$path: $!";
1188 my $data;
1189 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1190 aio_mlock $data; # mlock in background
1191
1192=item aio_mlockall $flags, $callback->($status)
1193
1194Calls the C<mlockall> function with the given C<$flags> (a combination of
1195C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1196
1197On systems that do not implement C<mlockall>, this function returns C<-1>
1198and sets errno to C<ENOSYS>.
1199
1200Note that the corresponding C<munlockall> is synchronous and is
1201documented under L<MISCELLANEOUS FUNCTIONS>.
1202
1203Example: asynchronously lock all current and future pages into memory.
1204
1205 aio_mlockall IO::AIO::MCL_FUTURE;
1206
898=item aio_group $callback->(...) 1207=item aio_group $callback->(...)
899 1208
900This is a very special aio request: Instead of doing something, it is a 1209This 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 1210container for other aio requests, which is useful if you want to bundle
902many requests into a single, composite, request with a definite callback 1211many requests into a single, composite, request with a definite callback
… …
951=item cancel $req 1260=item cancel $req
952 1261
953Cancels the request, if possible. Has the effect of skipping execution 1262Cancels the request, if possible. Has the effect of skipping execution
954when entering the B<execute> state and skipping calling the callback when 1263when entering the B<execute> state and skipping calling the callback when
955entering the the B<result> state, but will leave the request otherwise 1264entering the the B<result> state, but will leave the request otherwise
956untouched. That means that requests that currently execute will not be 1265untouched (with the exception of readdir). That means that requests that
957stopped and resources held by the request will not be freed prematurely. 1266currently execute will not be stopped and resources held by the request
1267will not be freed prematurely.
958 1268
959=item cb $req $callback->(...) 1269=item cb $req $callback->(...)
960 1270
961Replace (or simply set) the callback registered to the request. 1271Replace (or simply set) the callback registered to the request.
962 1272
… …
1013Their lifetime, simplified, looks like this: when they are empty, they 1323Their lifetime, simplified, looks like this: when they are empty, they
1014will finish very quickly. If they contain only requests that are in the 1324will finish very quickly. If they contain only requests that are in the
1015C<done> state, they will also finish. Otherwise they will continue to 1325C<done> state, they will also finish. Otherwise they will continue to
1016exist. 1326exist.
1017 1327
1018That means after creating a group you have some time to add requests. And 1328That 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 1329(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 1330the C<poll_cb>). And in the callbacks of those requests, you can add
1021itself finish. 1331further requests to the group. And only when all those requests have
1332finished will the the group itself finish.
1022 1333
1023=over 4 1334=over 4
1024 1335
1025=item add $grp ... 1336=item add $grp ...
1026 1337
… …
1034 1345
1035=item $grp->cancel_subs 1346=item $grp->cancel_subs
1036 1347
1037Cancel all subrequests and clears any feeder, but not the group request 1348Cancel 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. 1349itself. Useful when you queued a lot of events but got a result early.
1350
1351The group request will finish normally (you cannot add requests to the
1352group).
1039 1353
1040=item $grp->result (...) 1354=item $grp->result (...)
1041 1355
1042Set the result value(s) that will be passed to the group callback when all 1356Set 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 1357subrequests have finished and set the groups errno to the current value
… …
1059=item feed $grp $callback->($grp) 1373=item feed $grp $callback->($grp)
1060 1374
1061Sets a feeder/generator on this group: every group can have an attached 1375Sets a feeder/generator on this group: every group can have an attached
1062generator that generates requests if idle. The idea behind this is that, 1376generator 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, 1377although you could just queue as many requests as you want in a group,
1064this might starve other requests for a potentially long time. For 1378this might starve other requests for a potentially long time. For example,
1065example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1379C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1066requests, delaying any later requests for a long time. 1380delaying any later requests for a long time.
1067 1381
1068To avoid this, and allow incremental generation of requests, you can 1382To avoid this, and allow incremental generation of requests, you can
1069instead a group and set a feeder on it that generates those requests. The 1383instead 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>, 1384feed 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 1385below) requests active in the group itself and is expected to queue more
… …
1075not impose any limits). 1389not impose any limits).
1076 1390
1077If the feed does not queue more requests when called, it will be 1391If the feed does not queue more requests when called, it will be
1078automatically removed from the group. 1392automatically removed from the group.
1079 1393
1080If the feed limit is C<0>, it will be set to C<2> automatically. 1394If the feed limit is C<0> when this method is called, it will be set to
1395C<2> automatically.
1081 1396
1082Example: 1397Example:
1083 1398
1084 # stat all files in @files, but only ever use four aio requests concurrently: 1399 # stat all files in @files, but only ever use four aio requests concurrently:
1085 1400
… …
1097Sets the feeder limit for the group: The feeder will be called whenever 1412Sets the feeder limit for the group: The feeder will be called whenever
1098the group contains less than this many requests. 1413the group contains less than this many requests.
1099 1414
1100Setting the limit to C<0> will pause the feeding process. 1415Setting the limit to C<0> will pause the feeding process.
1101 1416
1417The default value for the limit is C<0>, but note that setting a feeder
1418automatically bumps it up to C<2>.
1419
1102=back 1420=back
1103 1421
1104=head2 SUPPORT FUNCTIONS 1422=head2 SUPPORT FUNCTIONS
1105 1423
1106=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1424=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1108=over 4 1426=over 4
1109 1427
1110=item $fileno = IO::AIO::poll_fileno 1428=item $fileno = IO::AIO::poll_fileno
1111 1429
1112Return the I<request result pipe file descriptor>. This filehandle must be 1430Return the I<request result pipe file descriptor>. This filehandle must be
1113polled for reading by some mechanism outside this module (e.g. Event or 1431polled 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 1432select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1115to call C<poll_cb> to check the results. 1433you have to call C<poll_cb> to check the results.
1116 1434
1117See C<poll_cb> for an example. 1435See C<poll_cb> for an example.
1118 1436
1119=item IO::AIO::poll_cb 1437=item IO::AIO::poll_cb
1120 1438
1121Process some outstanding events on the result pipe. You have to call this 1439Process some outstanding events on the result pipe. You have to call
1122regularly. Returns C<0> if all events could be processed, or C<-1> if it 1440this regularly. Returns C<0> if all events could be processed (or there
1123returned earlier for whatever reason. Returns immediately when no events 1441were no events to process), or C<-1> if it returned earlier for whatever
1124are outstanding. The amount of events processed depends on the settings of 1442reason. Returns immediately when no events are outstanding. The amount of
1125C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1443events processed depends on the settings of C<IO::AIO::max_poll_req> and
1444C<IO::AIO::max_poll_time>.
1126 1445
1127If not all requests were processed for whatever reason, the filehandle 1446If not all requests were processed for whatever reason, the filehandle
1128will still be ready when C<poll_cb> returns, so normally you don't have to 1447will still be ready when C<poll_cb> returns, so normally you don't have to
1129do anything special to have it called later. 1448do anything special to have it called later.
1130 1449
1450Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1451ready, it can be beneficial to call this function from loops which submit
1452a lot of requests, to make sure the results get processed when they become
1453available and not just when the loop is finished and the event loop takes
1454over again. This function returns very fast when there are no outstanding
1455requests.
1456
1131Example: Install an Event watcher that automatically calls 1457Example: Install an Event watcher that automatically calls
1132IO::AIO::poll_cb with high priority: 1458IO::AIO::poll_cb with high priority (more examples can be found in the
1459SYNOPSIS section, at the top of this document):
1133 1460
1134 Event->io (fd => IO::AIO::poll_fileno, 1461 Event->io (fd => IO::AIO::poll_fileno,
1135 poll => 'r', async => 1, 1462 poll => 'r', async => 1,
1136 cb => \&IO::AIO::poll_cb); 1463 cb => \&IO::AIO::poll_cb);
1464
1465=item IO::AIO::poll_wait
1466
1467If there are any outstanding requests and none of them in the result
1468phase, wait till the result filehandle becomes ready for reading (simply
1469does a C<select> on the filehandle. This is useful if you want to
1470synchronously wait for some requests to finish).
1471
1472See C<nreqs> for an example.
1473
1474=item IO::AIO::poll
1475
1476Waits until some requests have been handled.
1477
1478Returns the number of requests processed, but is otherwise strictly
1479equivalent to:
1480
1481 IO::AIO::poll_wait, IO::AIO::poll_cb
1482
1483=item IO::AIO::flush
1484
1485Wait till all outstanding AIO requests have been handled.
1486
1487Strictly equivalent to:
1488
1489 IO::AIO::poll_wait, IO::AIO::poll_cb
1490 while IO::AIO::nreqs;
1137 1491
1138=item IO::AIO::max_poll_reqs $nreqs 1492=item IO::AIO::max_poll_reqs $nreqs
1139 1493
1140=item IO::AIO::max_poll_time $seconds 1494=item IO::AIO::max_poll_time $seconds
1141 1495
… …
1166 # use a low priority so other tasks have priority 1520 # use a low priority so other tasks have priority
1167 Event->io (fd => IO::AIO::poll_fileno, 1521 Event->io (fd => IO::AIO::poll_fileno,
1168 poll => 'r', nice => 1, 1522 poll => 'r', nice => 1,
1169 cb => &IO::AIO::poll_cb); 1523 cb => &IO::AIO::poll_cb);
1170 1524
1171=item IO::AIO::poll_wait
1172
1173If there are any outstanding requests and none of them in the result
1174phase, wait till the result filehandle becomes ready for reading (simply
1175does a C<select> on the filehandle. This is useful if you want to
1176synchronously wait for some requests to finish).
1177
1178See C<nreqs> for an example.
1179
1180=item IO::AIO::poll
1181
1182Waits until some requests have been handled.
1183
1184Returns the number of requests processed, but is otherwise strictly
1185equivalent to:
1186
1187 IO::AIO::poll_wait, IO::AIO::poll_cb
1188
1189=item IO::AIO::flush
1190
1191Wait till all outstanding AIO requests have been handled.
1192
1193Strictly equivalent to:
1194
1195 IO::AIO::poll_wait, IO::AIO::poll_cb
1196 while IO::AIO::nreqs;
1197
1198=back 1525=back
1199 1526
1200=head3 CONTROLLING THE NUMBER OF THREADS 1527=head3 CONTROLLING THE NUMBER OF THREADS
1201 1528
1202=over 1529=over
… …
1235 1562
1236Under normal circumstances you don't need to call this function. 1563Under normal circumstances you don't need to call this function.
1237 1564
1238=item IO::AIO::max_idle $nthreads 1565=item IO::AIO::max_idle $nthreads
1239 1566
1240Limit the number of threads (default: 4) that are allowed to idle (i.e., 1567Limit the number of threads (default: 4) that are allowed to idle
1241threads that did not get a request to process within 10 seconds). That 1568(i.e., threads that did not get a request to process within the idle
1242means if a thread becomes idle while C<$nthreads> other threads are also 1569timeout (default: 10 seconds). That means if a thread becomes idle while
1243idle, it will free its resources and exit. 1570C<$nthreads> other threads are also idle, it will free its resources and
1571exit.
1244 1572
1245This is useful when you allow a large number of threads (e.g. 100 or 1000) 1573This is useful when you allow a large number of threads (e.g. 100 or 1000)
1246to allow for extremely high load situations, but want to free resources 1574to allow for extremely high load situations, but want to free resources
1247under normal circumstances (1000 threads can easily consume 30MB of RAM). 1575under normal circumstances (1000 threads can easily consume 30MB of RAM).
1248 1576
1249The default is probably ok in most situations, especially if thread 1577The default is probably ok in most situations, especially if thread
1250creation is fast. If thread creation is very slow on your system you might 1578creation is fast. If thread creation is very slow on your system you might
1251want to use larger values. 1579want to use larger values.
1252 1580
1581=item IO::AIO::idle_timeout $seconds
1582
1583Sets the minimum idle timeout (default 10) after which worker threads are
1584allowed to exit. SEe C<IO::AIO::max_idle>.
1585
1253=item IO::AIO::max_outstanding $maxreqs 1586=item IO::AIO::max_outstanding $maxreqs
1587
1588Sets the maximum number of outstanding requests to C<$nreqs>. If
1589you do queue up more than this number of requests, the next call to
1590C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1591C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1592longer exceeded.
1593
1594In other words, this setting does not enforce a queue limit, but can be
1595used to make poll functions block if the limit is exceeded.
1254 1596
1255This is a very bad function to use in interactive programs because it 1597This is a very bad function to use in interactive programs because it
1256blocks, and a bad way to reduce concurrency because it is inexact: Better 1598blocks, and a bad way to reduce concurrency because it is inexact: Better
1257use an C<aio_group> together with a feed callback. 1599use an C<aio_group> together with a feed callback.
1258 1600
1259Sets the maximum number of outstanding requests to C<$nreqs>. If you 1601It's main use is in scripts without an event loop - when you want to stat
1260do queue up more than this number of requests, the next call to the 1602a lot of files, you can write somehting like this:
1261C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1262function will block until the limit is no longer exceeded.
1263 1603
1264The default value is very large, so there is no practical limit on the 1604 IO::AIO::max_outstanding 32;
1265number of outstanding requests.
1266 1605
1267You can still queue as many requests as you want. Therefore, 1606 for my $path (...) {
1268C<max_outstanding> is mainly useful in simple scripts (with low values) or 1607 aio_stat $path , ...;
1269as a stop gap to shield against fatal memory overflow (with large values). 1608 IO::AIO::poll_cb;
1609 }
1610
1611 IO::AIO::flush;
1612
1613The call to C<poll_cb> inside the loop will normally return instantly, but
1614as soon as more thna C<32> reqeusts are in-flight, it will block until
1615some requests have been handled. This keeps the loop from pushing a large
1616number of C<aio_stat> requests onto the queue.
1617
1618The default value for C<max_outstanding> is very large, so there is no
1619practical limit on the number of outstanding requests.
1270 1620
1271=back 1621=back
1272 1622
1273=head3 STATISTICAL INFORMATION 1623=head3 STATISTICAL INFORMATION
1274 1624
… …
1294Returns the number of requests currently in the pending state (executed, 1644Returns the number of requests currently in the pending state (executed,
1295but not yet processed by poll_cb). 1645but not yet processed by poll_cb).
1296 1646
1297=back 1647=back
1298 1648
1649=head3 MISCELLANEOUS FUNCTIONS
1650
1651IO::AIO implements some functions that might be useful, but are not
1652asynchronous.
1653
1654=over 4
1655
1656=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1657
1658Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1659but is blocking (this makes most sense if you know the input data is
1660likely cached already and the output filehandle is set to non-blocking
1661operations).
1662
1663Returns the number of bytes copied, or C<-1> on error.
1664
1665=item IO::AIO::fadvise $fh, $offset, $len, $advice
1666
1667Simply calls the C<posix_fadvise> function (see its
1668manpage for details). The following advice constants are
1669avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1670C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1671C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1672
1673On systems that do not implement C<posix_fadvise>, this function returns
1674ENOSYS, otherwise the return value of C<posix_fadvise>.
1675
1676=item IO::AIO::madvise $scalar, $offset, $len, $advice
1677
1678Simply calls the C<posix_madvise> function (see its
1679manpage for details). The following advice constants are
1680avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1681C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1682
1683On systems that do not implement C<posix_madvise>, this function returns
1684ENOSYS, otherwise the return value of C<posix_madvise>.
1685
1686=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1687
1688Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1689$scalar (see its manpage for details). The following protect
1690constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1691C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1692
1693On systems that do not implement C<mprotect>, this function returns
1694ENOSYS, otherwise the return value of C<mprotect>.
1695
1696=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1697
1698Memory-maps a file (or anonymous memory range) and attaches it to the
1699given C<$scalar>, which will act like a string scalar.
1700
1701The only operations allowed on the scalar are C<substr>/C<vec> that don't
1702change the string length, and most read-only operations such as copying it
1703or searching it with regexes and so on.
1704
1705Anything else is unsafe and will, at best, result in memory leaks.
1706
1707The memory map associated with the C<$scalar> is automatically removed
1708when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1709C<IO::AIO::munmap> functions are called.
1710
1711This calls the C<mmap>(2) function internally. See your system's manual
1712page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1713
1714The C<$length> must be larger than zero and smaller than the actual
1715filesize.
1716
1717C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1718C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1719
1720C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1721C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1722not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1723(which is set to C<MAP_ANON> if your system only provides this
1724constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1725C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1726C<IO::AIO::MAP_NONBLOCK>
1727
1728If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1729
1730C<$offset> is the offset from the start of the file - it generally must be
1731a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1732
1733Example:
1734
1735 use Digest::MD5;
1736 use IO::AIO;
1737
1738 open my $fh, "<verybigfile"
1739 or die "$!";
1740
1741 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1742 or die "verybigfile: $!";
1743
1744 my $fast_md5 = md5 $data;
1745
1746=item IO::AIO::munmap $scalar
1747
1748Removes a previous mmap and undefines the C<$scalar>.
1749
1750=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1751
1752Calls the C<munlock> function, undoing the effects of a previous
1753C<aio_mlock> call (see its description for details).
1754
1755=item IO::AIO::munlockall
1756
1757Calls the C<munlockall> function.
1758
1759On systems that do not implement C<munlockall>, this function returns
1760ENOSYS, otherwise the return value of C<munlockall>.
1761
1762=back
1763
1299=cut 1764=cut
1300 1765
1301min_parallel 8; 1766min_parallel 8;
1302 1767
1303END { flush } 1768END { flush }
1304 1769
13051; 17701;
1306 1771
1772=head1 EVENT LOOP INTEGRATION
1773
1774It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1775automatically into many event loops:
1776
1777 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1778 use AnyEvent::AIO;
1779
1780You can also integrate IO::AIO manually into many event loops, here are
1781some examples of how to do this:
1782
1783 # EV integration
1784 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1785
1786 # Event integration
1787 Event->io (fd => IO::AIO::poll_fileno,
1788 poll => 'r',
1789 cb => \&IO::AIO::poll_cb);
1790
1791 # Glib/Gtk2 integration
1792 add_watch Glib::IO IO::AIO::poll_fileno,
1793 in => sub { IO::AIO::poll_cb; 1 };
1794
1795 # Tk integration
1796 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1797 readable => \&IO::AIO::poll_cb);
1798
1799 # Danga::Socket integration
1800 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1801 \&IO::AIO::poll_cb);
1802
1307=head2 FORK BEHAVIOUR 1803=head2 FORK BEHAVIOUR
1308 1804
1309This module should do "the right thing" when the process using it forks: 1805Usage of pthreads in a program changes the semantics of fork
1806considerably. Specifically, only async-safe functions can be called after
1807fork. Perl doesn't know about this, so in general, you cannot call fork
1808with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1809but many other extensions and (for inexplicable reasons) perl itself often
1810is linked against pthreads, so this limitation applies.
1310 1811
1311Before the fork, IO::AIO enters a quiescent state where no requests 1812Some operating systems have extensions that allow safe use of fork, and
1312can be added in other threads and no results will be processed. After 1813this module should do "the right thing" on those, and tries on others. At
1313the fork the parent simply leaves the quiescent state and continues 1814the time of this writing (2011) only GNU/Linux supports these extensions
1314request/result processing, while the child frees the request/result queue 1815to POSIX.
1315(so that the requests started before the fork will only be handled in the
1316parent). Threads will be started on demand until the limit set in the
1317parent process has been reached again.
1318
1319In short: the parent will, after a short pause, continue as if fork had
1320not been called, while the child will act as if IO::AIO has not been used
1321yet.
1322 1816
1323=head2 MEMORY USAGE 1817=head2 MEMORY USAGE
1324 1818
1325Per-request usage: 1819Per-request usage:
1326 1820

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