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Revision 1.124 by root, Sat May 10 19:25:33 2008 UTC vs.
Revision 1.197 by root, Wed Jun 29 10:49:35 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, urxvt, pureperl...)
32 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35 # EV integration
36 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
37
38 # Event integration
39 Event->io (fd => IO::AIO::poll_fileno,
40 poll => 'r',
41 cb => \&IO::AIO::poll_cb);
42
43 # Glib/Gtk2 integration
44 add_watch Glib::IO IO::AIO::poll_fileno,
45 in => sub { IO::AIO::poll_cb; 1 };
46
47 # Tk integration
48 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
49 readable => \&IO::AIO::poll_cb);
50
51 # Danga::Socket integration
52 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
53 \&IO::AIO::poll_cb);
54
55=head1 DESCRIPTION 31=head1 DESCRIPTION
56 32
57This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
58operating system supports. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
59 36
60Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
61(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
62will 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
63is 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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67on 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
68concurrently. 45concurrently.
69 46
70While most of this works on all types of file descriptors (for 47While most of this works on all types of file descriptors (for
71example sockets), using these functions on file descriptors that 48example sockets), using these functions on file descriptors that
72support nonblocking operation (again, sockets, pipes etc.) is very 49support nonblocking operation (again, sockets, pipes etc.) is
73inefficient. 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>
74module): IO::AIO will naturally fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
75 52
76In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
77requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
78in 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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88yourself, 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
89call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
90 67
91=head2 EXAMPLE 68=head2 EXAMPLE
92 69
93This is a simple example that uses the Event module and loads 70This is a simple example that uses the EV module and loads
94F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
95 72
96 use Fcntl; 73 use Fcntl;
97 use Event; 74 use EV;
98 use IO::AIO; 75 use IO::AIO;
99 76
100 # register the IO::AIO callback with Event 77 # register the IO::AIO callback with EV
101 Event->io (fd => IO::AIO::poll_fileno, 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 poll => 'r',
103 cb => \&IO::AIO::poll_cb);
104 79
105 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
106 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
107 my $fh = shift 82 my $fh = shift
108 or die "error while opening: $!"; 83 or die "error while opening: $!";
109 84
110 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
111 my $size = -s $fh; 86 my $size = -s $fh;
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120 95
121 # file contents now in $contents 96 # file contents now in $contents
122 print $contents; 97 print $contents;
123 98
124 # exit event loop and program 99 # exit event loop and program
125 Event::unloop; 100 EV::unloop;
126 }; 101 };
127 }; 102 };
128 103
129 # possibly queue up other requests, or open GUI windows, 104 # possibly queue up other requests, or open GUI windows,
130 # check for sockets etc. etc. 105 # check for sockets etc. etc.
131 106
132 # process events as long as there are some: 107 # process events as long as there are some:
133 Event::loop; 108 EV::loop;
134 109
135=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
136 111
137Every 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
138directly visible to Perl. 113directly visible to Perl.
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188 163
189package IO::AIO; 164package IO::AIO;
190 165
191use Carp (); 166use Carp ();
192 167
193no warnings; 168use common::sense;
194use strict 'vars';
195 169
196use base 'Exporter'; 170use base 'Exporter';
197 171
198BEGIN { 172BEGIN {
199 our $VERSION = '3.0'; 173 our $VERSION = '3.9';
200 174
201 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
202 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
203 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
204 aio_fdatasync aio_pathsync aio_readahead 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
205 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
206 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
207 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);
208 184
209 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
210 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
211 min_parallel max_parallel max_idle 187 min_parallel max_parallel max_idle idle_timeout
212 nreqs nready npending nthreads 188 nreqs nready npending nthreads
213 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
214 194
215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
216 196
217 require XSLoader; 197 require XSLoader;
218 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
219} 199}
220 200
221=head1 FUNCTIONS 201=head1 FUNCTIONS
202
203=head2 QUICK OVERVIEW
204
205This section simply lists the prototypes of the most important functions
206for quick reference. See the following sections for function-by-function
207documentation.
208
209 aio_open $pathname, $flags, $mode, $callback->($fh)
210 aio_close $fh, $callback->($status)
211 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214 aio_readahead $fh,$offset,$length, $callback->($retval)
215 aio_stat $fh_or_path, $callback->($status)
216 aio_lstat $fh, $callback->($status)
217 aio_statvfs $fh_or_path, $callback->($statvfs)
218 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
220 aio_truncate $fh_or_path, $offset, $callback->($status)
221 aio_chmod $fh_or_path, $mode, $callback->($status)
222 aio_unlink $pathname, $callback->($status)
223 aio_mknod $path, $mode, $dev, $callback->($status)
224 aio_link $srcpath, $dstpath, $callback->($status)
225 aio_symlink $srcpath, $dstpath, $callback->($status)
226 aio_readlink $path, $callback->($link)
227 aio_rename $srcpath, $dstpath, $callback->($status)
228 aio_mkdir $pathname, $mode, $callback->($status)
229 aio_rmdir $pathname, $callback->($status)
230 aio_readdir $pathname, $callback->($entries)
231 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
234 aio_load $path, $data, $callback->($status)
235 aio_copy $srcpath, $dstpath, $callback->($status)
236 aio_move $srcpath, $dstpath, $callback->($status)
237 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238 aio_rmtree $path, $callback->($status)
239 aio_sync $callback->($status)
240 aio_fsync $fh, $callback->($status)
241 aio_fdatasync $fh, $callback->($status)
242 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243 aio_pathsync $path, $callback->($status)
244 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247 aio_mlockall $flags, $callback->($status)
248 aio_group $callback->(...)
249 aio_nop $callback->()
250
251 $prev_pri = aioreq_pri [$pri]
252 aioreq_nice $pri_adjust
253
254 IO::AIO::poll_wait
255 IO::AIO::poll_cb
256 IO::AIO::poll
257 IO::AIO::flush
258 IO::AIO::max_poll_reqs $nreqs
259 IO::AIO::max_poll_time $seconds
260 IO::AIO::min_parallel $nthreads
261 IO::AIO::max_parallel $nthreads
262 IO::AIO::max_idle $nthreads
263 IO::AIO::idle_timeout $seconds
264 IO::AIO::max_outstanding $maxreqs
265 IO::AIO::nreqs
266 IO::AIO::nready
267 IO::AIO::npending
268
269 IO::AIO::sendfile $ofh, $ifh, $offset, $count
270 IO::AIO::fadvise $fh, $offset, $len, $advice
271 IO::AIO::madvise $scalar, $offset, $length, $advice
272 IO::AIO::mprotect $scalar, $offset, $length, $protect
273 IO::AIO::munlock $scalar, $offset = 0, $length = undef
274 IO::AIO::munlockall
222 275
223=head2 AIO REQUEST FUNCTIONS 276=head2 AIO REQUEST FUNCTIONS
224 277
225All the C<aio_*> calls are more or less thin wrappers around the syscall 278All the C<aio_*> calls are more or less thin wrappers around the syscall
226with the same name (sans C<aio_>). The arguments are similar or identical, 279with the same name (sans C<aio_>). The arguments are similar or identical,
227and they all accept an additional (and optional) C<$callback> argument 280and they all accept an additional (and optional) C<$callback> argument
228which must be a code reference. This code reference will get called with 281which must be a code reference. This code reference will get called with
229the syscall return code (e.g. most syscalls return C<-1> on error, unlike 282the syscall return code (e.g. most syscalls return C<-1> on error, unlike
230perl, which usually delivers "false") as it's sole argument when the given 283perl, which usually delivers "false") as its sole argument after the given
231syscall has been executed asynchronously. 284syscall has been executed asynchronously.
232 285
233All functions expecting a filehandle keep a copy of the filehandle 286All functions expecting a filehandle keep a copy of the filehandle
234internally until the request has finished. 287internally until the request has finished.
235 288
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249your pathnames to the locale (or other) encoding in effect in the user 302your pathnames to the locale (or other) encoding in effect in the user
250environment, d) use Glib::filename_from_unicode on unicode filenames or e) 303environment, d) use Glib::filename_from_unicode on unicode filenames or e)
251use something else to ensure your scalar has the correct contents. 304use something else to ensure your scalar has the correct contents.
252 305
253This works, btw. independent of the internal UTF-8 bit, which IO::AIO 306This works, btw. independent of the internal UTF-8 bit, which IO::AIO
254handles correctly wether it is set or not. 307handles correctly whether it is set or not.
255 308
256=over 4 309=over 4
257 310
258=item $prev_pri = aioreq_pri [$pri] 311=item $prev_pri = aioreq_pri [$pri]
259 312
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306by the umask in effect then the request is being executed, so better never 359by the umask in effect then the request is being executed, so better never
307change the umask. 360change the umask.
308 361
309Example: 362Example:
310 363
311 aio_open "/etc/passwd", O_RDONLY, 0, sub { 364 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
312 if ($_[0]) { 365 if ($_[0]) {
313 print "open successful, fh is $_[0]\n"; 366 print "open successful, fh is $_[0]\n";
314 ... 367 ...
315 } else { 368 } else {
316 die "open failed: $!\n"; 369 die "open failed: $!\n";
317 } 370 }
318 }; 371 };
319 372
373In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
374C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
375following POSIX and non-POSIX constants are available (missing ones on
376your system are, as usual, C<0>):
377
378C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
379C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
380C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
381
320 382
321=item aio_close $fh, $callback->($status) 383=item aio_close $fh, $callback->($status)
322 384
323Asynchronously close a file and call the callback with the result 385Asynchronously close a file and call the callback with the result
324code. 386code.
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337 399
338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 400=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
339 401
340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 402=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
341 403
342Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 404Reads or writes C<$length> bytes from or to the specified C<$fh> and
343into the scalar given by C<$data> and offset C<$dataoffset> and calls the 405C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
344callback without the actual number of bytes read (or -1 on error, just 406and calls the callback without the actual number of bytes read (or -1 on
345like the syscall). 407error, just like the syscall).
408
409C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
410offset plus the actual number of bytes read.
346 411
347If C<$offset> is undefined, then the current file descriptor offset will 412If C<$offset> is undefined, then the current file descriptor offset will
348be used (and updated), otherwise the file descriptor offset will not be 413be used (and updated), otherwise the file descriptor offset will not be
349changed by these calls. 414changed by these calls.
350 415
351If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 416If C<$length> is undefined in C<aio_write>, use the remaining length of
417C<$data>.
352 418
353If C<$dataoffset> is less than zero, it will be counted from the end of 419If C<$dataoffset> is less than zero, it will be counted from the end of
354C<$data>. 420C<$data>.
355 421
356The C<$data> scalar I<MUST NOT> be modified in any way while the request 422The C<$data> scalar I<MUST NOT> be modified in any way while the request
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370 436
371Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 437Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
372reading at byte offset C<$in_offset>, and starts writing at the current 438reading at byte offset C<$in_offset>, and starts writing at the current
373file offset of C<$out_fh>. Because of that, it is not safe to issue more 439file offset of C<$out_fh>. Because of that, it is not safe to issue more
374than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 440than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
375other. 441other. The same C<$in_fh> works fine though, as this function does not
442move or use the file offset of C<$in_fh>.
376 443
444Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
445are written, and there is no way to find out how many more bytes have been
446read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
447number of bytes written to C<$out_fh>. Only if the result value equals
448C<$length> one can assume that C<$length> bytes have been read.
449
450Unlike with other C<aio_> functions, it makes a lot of sense to use
451C<aio_sendfile> on non-blocking sockets, as long as one end (typically
452the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
453the socket I/O will be non-blocking. Note, however, that you can run
454into a trap where C<aio_sendfile> reads some data with readahead, then
455fails to write all data, and when the socket is ready the next time, the
456data in the cache is already lost, forcing C<aio_sendfile> to again hit
457the disk. Explicit C<aio_read> + C<aio_write> let's you better control
458resource usage.
459
377This call tries to make use of a native C<sendfile> syscall to provide 460This call tries to make use of a native C<sendfile>-like syscall to
378zero-copy operation. For this to work, C<$out_fh> should refer to a 461provide zero-copy operation. For this to work, C<$out_fh> should refer to
379socket, and C<$in_fh> should refer to mmap'able file. 462a socket, and C<$in_fh> should refer to an mmap'able file.
380 463
381If the native sendfile call fails or is not implemented, it will be 464If a native sendfile cannot be found or it fails with C<ENOSYS>,
382emulated, so you can call C<aio_sendfile> on any type of filehandle 465C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
466C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
383regardless of the limitations of the operating system. 467type of filehandle regardless of the limitations of the operating system.
384 468
385Please note, however, that C<aio_sendfile> can read more bytes from 469As native sendfile syscalls (as practically any non-POSIX interface hacked
386C<$in_fh> than are written, and there is no way to find out how many 470together in a hurry to improve benchmark numbers) tend to be rather buggy
387bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 471on many systems, this implementation tries to work around some known bugs
388provides the number of bytes written to C<$out_fh>. Only if the result 472in Linux and FreeBSD kernels (probably others, too), but that might fail,
389value equals C<$length> one can assume that C<$length> bytes have been 473so you really really should check the return value of C<aio_sendfile> -
390read. 474fewre bytes than expected might have been transferred.
391 475
392 476
393=item aio_readahead $fh,$offset,$length, $callback->($retval) 477=item aio_readahead $fh,$offset,$length, $callback->($retval)
394 478
395C<aio_readahead> populates the page cache with data from a file so that 479C<aio_readahead> populates the page cache with data from a file so that
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418 502
419Currently, the stats are always 64-bit-stats, i.e. instead of returning an 503Currently, the stats are always 64-bit-stats, i.e. instead of returning an
420error when stat'ing a large file, the results will be silently truncated 504error when stat'ing a large file, the results will be silently truncated
421unless perl itself is compiled with large file support. 505unless perl itself is compiled with large file support.
422 506
507To help interpret the mode and dev/rdev stat values, IO::AIO offers the
508following constants and functions (if not implemented, the constants will
509be C<0> and the functions will either C<croak> or fall back on traditional
510behaviour).
511
512C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
513C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
514C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
515
423Example: Print the length of F</etc/passwd>: 516Example: Print the length of F</etc/passwd>:
424 517
425 aio_stat "/etc/passwd", sub { 518 aio_stat "/etc/passwd", sub {
426 $_[0] and die "stat failed: $!"; 519 $_[0] and die "stat failed: $!";
427 print "size is ", -s _, "\n"; 520 print "size is ", -s _, "\n";
428 }; 521 };
429 522
430 523
524=item aio_statvfs $fh_or_path, $callback->($statvfs)
525
526Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
527whether a file handle or path was passed.
528
529On success, the callback is passed a hash reference with the following
530members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
531C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
532is passed.
533
534The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
535C<ST_NOSUID>.
536
537The following non-POSIX IO::AIO::ST_* flag masks are defined to
538their correct value when available, or to C<0> on systems that do
539not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
540C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
541C<ST_NODIRATIME> and C<ST_RELATIME>.
542
543Example: stat C</wd> and dump out the data if successful.
544
545 aio_statvfs "/wd", sub {
546 my $f = $_[0]
547 or die "statvfs: $!";
548
549 use Data::Dumper;
550 say Dumper $f;
551 };
552
553 # result:
554 {
555 bsize => 1024,
556 bfree => 4333064312,
557 blocks => 10253828096,
558 files => 2050765568,
559 flag => 4096,
560 favail => 2042092649,
561 bavail => 4333064312,
562 ffree => 2042092649,
563 namemax => 255,
564 frsize => 1024,
565 fsid => 1810
566 }
567
568
431=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 569=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
432 570
433Works like perl's C<utime> function (including the special case of $atime 571Works like perl's C<utime> function (including the special case of $atime
434and $mtime being undef). Fractional times are supported if the underlying 572and $mtime being undef). Fractional times are supported if the underlying
435syscalls support them. 573syscalls support them.
… …
483 621
484The only (POSIX-) portable way of calling this function is: 622The only (POSIX-) portable way of calling this function is:
485 623
486 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 624 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
487 625
626See C<aio_stat> for info about some potentially helpful extra constants
627and functions.
488 628
489=item aio_link $srcpath, $dstpath, $callback->($status) 629=item aio_link $srcpath, $dstpath, $callback->($status)
490 630
491Asynchronously create a new link to the existing object at C<$srcpath> at 631Asynchronously create a new link to the existing object at C<$srcpath> at
492the path C<$dstpath> and call the callback with the result code. 632the path C<$dstpath> and call the callback with the result code.
… …
528 668
529Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 669Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
530directory (i.e. opendir + readdir + closedir). The entries will not be 670directory (i.e. opendir + readdir + closedir). The entries will not be
531sorted, and will B<NOT> include the C<.> and C<..> entries. 671sorted, and will B<NOT> include the C<.> and C<..> entries.
532 672
533The callback a single argument which is either C<undef> or an array-ref 673The callback is passed a single argument which is either C<undef> or an
534with the filenames. 674array-ref with the filenames.
675
676
677=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
678
679Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
680behaviour and output format. In case of an error, C<$entries> will be
681C<undef>.
682
683The flags are a combination of the following constants, ORed together (the
684flags will also be passed to the callback, possibly modified):
685
686=over 4
687
688=item IO::AIO::READDIR_DENTS
689
690When this flag is off, then the callback gets an arrayref consisting of
691names only (as with C<aio_readdir>), otherwise it gets an arrayref with
692C<[$name, $type, $inode]> arrayrefs, each describing a single directory
693entry in more detail.
694
695C<$name> is the name of the entry.
696
697C<$type> is one of the C<IO::AIO::DT_xxx> constants:
698
699C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
700C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
701C<IO::AIO::DT_WHT>.
702
703C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
704know, you have to run stat yourself. Also, for speed reasons, the C<$type>
705scalars are read-only: you can not modify them.
706
707C<$inode> is the inode number (which might not be exact on systems with 64
708bit inode numbers and 32 bit perls). This field has unspecified content on
709systems that do not deliver the inode information.
710
711=item IO::AIO::READDIR_DIRS_FIRST
712
713When this flag is set, then the names will be returned in an order where
714likely directories come first, in optimal stat order. This is useful when
715you need to quickly find directories, or you want to find all directories
716while avoiding to stat() each entry.
717
718If the system returns type information in readdir, then this is used
719to find directories directly. Otherwise, likely directories are names
720beginning with ".", or otherwise names with no dots, of which names with
721short names are tried first.
722
723=item IO::AIO::READDIR_STAT_ORDER
724
725When this flag is set, then the names will be returned in an order
726suitable for stat()'ing each one. That is, when you plan to stat()
727all files in the given directory, then the returned order will likely
728be fastest.
729
730If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
731the likely dirs come first, resulting in a less optimal stat order.
732
733=item IO::AIO::READDIR_FOUND_UNKNOWN
734
735This flag should not be set when calling C<aio_readdirx>. Instead, it
736is being set by C<aio_readdirx>, when any of the C<$type>'s found were
737C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
738C<$type>'s are known, which can be used to speed up some algorithms.
739
740=back
535 741
536 742
537=item aio_load $path, $data, $callback->($status) 743=item aio_load $path, $data, $callback->($status)
538 744
539This is a composite request that tries to fully load the given file into 745This is a composite request that tries to fully load the given file into
… …
564 770
565=item aio_copy $srcpath, $dstpath, $callback->($status) 771=item aio_copy $srcpath, $dstpath, $callback->($status)
566 772
567Try to copy the I<file> (directories not supported as either source or 773Try to copy the I<file> (directories not supported as either source or
568destination) from C<$srcpath> to C<$dstpath> and call the callback with 774destination) from C<$srcpath> to C<$dstpath> and call the callback with
569the C<0> (error) or C<-1> ok. 775a status of C<0> (ok) or C<-1> (error, see C<$!>).
570 776
571This is a composite request that it creates the destination file with 777This is a composite request that creates the destination file with
572mode 0200 and copies the contents of the source file into it using 778mode 0200 and copies the contents of the source file into it using
573C<aio_sendfile>, followed by restoring atime, mtime, access mode and 779C<aio_sendfile>, followed by restoring atime, mtime, access mode and
574uid/gid, in that order. 780uid/gid, in that order.
575 781
576If an error occurs, the partial destination file will be unlinked, if 782If an error occurs, the partial destination file will be unlinked, if
… …
586 my $grp = aio_group $cb; 792 my $grp = aio_group $cb;
587 793
588 aioreq_pri $pri; 794 aioreq_pri $pri;
589 add $grp aio_open $src, O_RDONLY, 0, sub { 795 add $grp aio_open $src, O_RDONLY, 0, sub {
590 if (my $src_fh = $_[0]) { 796 if (my $src_fh = $_[0]) {
591 my @stat = stat $src_fh; 797 my @stat = stat $src_fh; # hmm, might block over nfs?
592 798
593 aioreq_pri $pri; 799 aioreq_pri $pri;
594 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 800 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
595 if (my $dst_fh = $_[0]) { 801 if (my $dst_fh = $_[0]) {
596 aioreq_pri $pri; 802 aioreq_pri $pri;
597 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 803 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
598 if ($_[0] == $stat[7]) { 804 if ($_[0] == $stat[7]) {
599 $grp->result (0); 805 $grp->result (0);
600 close $src_fh; 806 close $src_fh;
601 807
602 # those should not normally block. should. should. 808 my $ch = sub {
603 utime $stat[8], $stat[9], $dst; 809 aioreq_pri $pri;
604 chmod $stat[2] & 07777, $dst_fh; 810 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
605 chown $stat[4], $stat[5], $dst_fh; 811 aioreq_pri $pri;
812 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
813 aioreq_pri $pri;
814 add $grp aio_close $dst_fh;
815 }
816 };
817 };
606 818
607 aioreq_pri $pri; 819 aioreq_pri $pri;
608 add $grp aio_close $dst_fh; 820 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
821 if ($_[0] < 0 && $! == ENOSYS) {
822 aioreq_pri $pri;
823 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
824 } else {
825 $ch->();
826 }
827 };
609 } else { 828 } else {
610 $grp->result (-1); 829 $grp->result (-1);
611 close $src_fh; 830 close $src_fh;
612 close $dst_fh; 831 close $dst_fh;
613 832
… …
630 849
631=item aio_move $srcpath, $dstpath, $callback->($status) 850=item aio_move $srcpath, $dstpath, $callback->($status)
632 851
633Try to move the I<file> (directories not supported as either source or 852Try to move the I<file> (directories not supported as either source or
634destination) from C<$srcpath> to C<$dstpath> and call the callback with 853destination) from C<$srcpath> to C<$dstpath> and call the callback with
635the C<0> (error) or C<-1> ok. 854a status of C<0> (ok) or C<-1> (error, see C<$!>).
636 855
637This is a composite request that tries to rename(2) the file first. If 856This is a composite request that tries to rename(2) the file first; if
638rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 857rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
639that is successful, unlinking the C<$srcpath>. 858that is successful, unlinks the C<$srcpath>.
640 859
641=cut 860=cut
642 861
643sub aio_move($$;$) { 862sub aio_move($$;$) {
644 my ($src, $dst, $cb) = @_; 863 my ($src, $dst, $cb) = @_;
… …
651 if ($_[0] && $! == EXDEV) { 870 if ($_[0] && $! == EXDEV) {
652 aioreq_pri $pri; 871 aioreq_pri $pri;
653 add $grp aio_copy $src, $dst, sub { 872 add $grp aio_copy $src, $dst, sub {
654 $grp->result ($_[0]); 873 $grp->result ($_[0]);
655 874
656 if (!$_[0]) { 875 unless ($_[0]) {
657 aioreq_pri $pri; 876 aioreq_pri $pri;
658 add $grp aio_unlink $src; 877 add $grp aio_unlink $src;
659 } 878 }
660 }; 879 };
661 } else { 880 } else {
… …
691 910
692Implementation notes. 911Implementation notes.
693 912
694The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 913The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
695 914
915If readdir returns file type information, then this is used directly to
916find directories.
917
696After reading the directory, the modification time, size etc. of the 918Otherwise, after reading the directory, the modification time, size etc.
697directory before and after the readdir is checked, and if they match (and 919of the directory before and after the readdir is checked, and if they
698isn't the current time), the link count will be used to decide how many 920match (and isn't the current time), the link count will be used to decide
699entries are directories (if >= 2). Otherwise, no knowledge of the number 921how many entries are directories (if >= 2). Otherwise, no knowledge of the
700of subdirectories will be assumed. 922number of subdirectories will be assumed.
701 923
702Then entries will be sorted into likely directories (everything without 924Then entries will be sorted into likely directories a non-initial dot
703a non-initial dot currently) and likely non-directories (everything 925currently) and likely non-directories (see C<aio_readdirx>). Then every
704else). Then every entry plus an appended C</.> will be C<stat>'ed, 926entry plus an appended C</.> will be C<stat>'ed, likely directories first,
705likely directories first. If that succeeds, it assumes that the entry 927in order of their inode numbers. If that succeeds, it assumes that the
706is a directory or a symlink to directory (which will be checked 928entry is a directory or a symlink to directory (which will be checked
707seperately). This is often faster than stat'ing the entry itself because 929seperately). This is often faster than stat'ing the entry itself because
708filesystems might detect the type of the entry without reading the inode 930filesystems might detect the type of the entry without reading the inode
709data (e.g. ext2fs filetype feature). 931data (e.g. ext2fs filetype feature), even on systems that cannot return
932the filetype information on readdir.
710 933
711If the known number of directories (link count - 2) has been reached, the 934If the known number of directories (link count - 2) has been reached, the
712rest of the entries is assumed to be non-directories. 935rest of the entries is assumed to be non-directories.
713 936
714This only works with certainty on POSIX (= UNIX) filesystems, which 937This only works with certainty on POSIX (= UNIX) filesystems, which
… …
736 my $now = time; 959 my $now = time;
737 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 960 my $hash1 = join ":", (stat _)[0,1,3,7,9];
738 961
739 # read the directory entries 962 # read the directory entries
740 aioreq_pri $pri; 963 aioreq_pri $pri;
741 add $grp aio_readdir $path, sub { 964 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
742 my $entries = shift 965 my $entries = shift
743 or return $grp->result (); 966 or return $grp->result ();
744 967
745 # stat the dir another time 968 # stat the dir another time
746 aioreq_pri $pri; 969 aioreq_pri $pri;
… …
752 # take the slow route if anything looks fishy 975 # take the slow route if anything looks fishy
753 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 976 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
754 $ndirs = -1; 977 $ndirs = -1;
755 } else { 978 } else {
756 # if nlink == 2, we are finished 979 # if nlink == 2, we are finished
757 # on non-posix-fs's, we rely on nlink < 2 980 # for non-posix-fs's, we rely on nlink < 2
758 $ndirs = (stat _)[3] - 2 981 $ndirs = (stat _)[3] - 2
759 or return $grp->result ([], $entries); 982 or return $grp->result ([], $entries);
760 } 983 }
761 984
762 # sort into likely dirs and likely nondirs
763 # dirs == files without ".", short entries first
764 $entries = [map $_->[0],
765 sort { $b->[1] cmp $a->[1] }
766 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
767 @$entries];
768
769 my (@dirs, @nondirs); 985 my (@dirs, @nondirs);
770 986
771 my $statgrp = add $grp aio_group sub { 987 my $statgrp = add $grp aio_group sub {
772 $grp->result (\@dirs, \@nondirs); 988 $grp->result (\@dirs, \@nondirs);
773 }; 989 };
774 990
775 limit $statgrp $maxreq; 991 limit $statgrp $maxreq;
776 feed $statgrp sub { 992 feed $statgrp sub {
777 return unless @$entries; 993 return unless @$entries;
778 my $entry = pop @$entries; 994 my $entry = shift @$entries;
779 995
780 aioreq_pri $pri; 996 aioreq_pri $pri;
781 add $statgrp aio_stat "$path/$entry/.", sub { 997 add $statgrp aio_stat "$path/$entry/.", sub {
782 if ($_[0] < 0) { 998 if ($_[0] < 0) {
783 push @nondirs, $entry; 999 push @nondirs, $entry;
… …
856callback with the fdatasync result code. 1072callback with the fdatasync result code.
857 1073
858If this call isn't available because your OS lacks it or it couldn't be 1074If this call isn't available because your OS lacks it or it couldn't be
859detected, it will be emulated by calling C<fsync> instead. 1075detected, it will be emulated by calling C<fsync> instead.
860 1076
1077=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1078
1079Sync the data portion of the file specified by C<$offset> and C<$length>
1080to disk (but NOT the metadata), by calling the Linux-specific
1081sync_file_range call. If sync_file_range is not available or it returns
1082ENOSYS, then fdatasync or fsync is being substituted.
1083
1084C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1085C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1086C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1087manpage for details.
1088
861=item aio_pathsync $path, $callback->($status) 1089=item aio_pathsync $path, $callback->($status)
862 1090
863This request tries to open, fsync and close the given path. This is a 1091This request tries to open, fsync and close the given path. This is a
864composite request intended tosync directories after directory operations 1092composite request intended to sync directories after directory operations
865(E.g. rename). This might not work on all operating systems or have any 1093(E.g. rename). This might not work on all operating systems or have any
866specific effect, but usually it makes sure that directory changes get 1094specific effect, but usually it makes sure that directory changes get
867written to disc. It works for anything that can be opened for read-only, 1095written to disc. It works for anything that can be opened for read-only,
868not just directories. 1096not just directories.
1097
1098Future versions of this function might fall back to other methods when
1099C<fsync> on the directory fails (such as calling C<sync>).
869 1100
870Passes C<0> when everything went ok, and C<-1> on error. 1101Passes C<0> when everything went ok, and C<-1> on error.
871 1102
872=cut 1103=cut
873 1104
… …
894 }; 1125 };
895 1126
896 $grp 1127 $grp
897} 1128}
898 1129
1130=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1131
1132This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1133scalars (see the C<IO::AIO::mmap> function, although it also works on data
1134scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1135scalar must only be modified in-place while an aio operation is pending on
1136it).
1137
1138It calls the C<msync> function of your OS, if available, with the memory
1139area starting at C<$offset> in the string and ending C<$length> bytes
1140later. If C<$length> is negative, counts from the end, and if C<$length>
1141is C<undef>, then it goes till the end of the string. The flags can be
1142a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1143C<IO::AIO::MS_SYNC>.
1144
1145=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1146
1147This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1148scalars.
1149
1150It touches (reads or writes) all memory pages in the specified
1151range inside the scalar. All caveats and parameters are the same
1152as for C<aio_msync>, above, except for flags, which must be either
1153C<0> (which reads all pages and ensures they are instantiated) or
1154C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1155writing an octet from it, which dirties the page).
1156
1157=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1158
1159This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1160scalars.
1161
1162It reads in all the pages of the underlying storage into memory (if any)
1163and locks them, so they are not getting swapped/paged out or removed.
1164
1165If C<$length> is undefined, then the scalar will be locked till the end.
1166
1167On systems that do not implement C<mlock>, this function returns C<-1>
1168and sets errno to C<ENOSYS>.
1169
1170Note that the corresponding C<munlock> is synchronous and is
1171documented under L<MISCELLANEOUS FUNCTIONS>.
1172
1173Example: open a file, mmap and mlock it - both will be undone when
1174C<$data> gets destroyed.
1175
1176 open my $fh, "<", $path or die "$path: $!";
1177 my $data;
1178 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1179 aio_mlock $data; # mlock in background
1180
1181=item aio_mlockall $flags, $callback->($status)
1182
1183Calls the C<mlockall> function with the given C<$flags> (a combination of
1184C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1185
1186On systems that do not implement C<mlockall>, this function returns C<-1>
1187and sets errno to C<ENOSYS>.
1188
1189Note that the corresponding C<munlockall> is synchronous and is
1190documented under L<MISCELLANEOUS FUNCTIONS>.
1191
1192Example: asynchronously lock all current and future pages into memory.
1193
1194 aio_mlockall IO::AIO::MCL_FUTURE;
1195
899=item aio_group $callback->(...) 1196=item aio_group $callback->(...)
900 1197
901This is a very special aio request: Instead of doing something, it is a 1198This is a very special aio request: Instead of doing something, it is a
902container for other aio requests, which is useful if you want to bundle 1199container for other aio requests, which is useful if you want to bundle
903many requests into a single, composite, request with a definite callback 1200many requests into a single, composite, request with a definite callback
… …
952=item cancel $req 1249=item cancel $req
953 1250
954Cancels the request, if possible. Has the effect of skipping execution 1251Cancels the request, if possible. Has the effect of skipping execution
955when entering the B<execute> state and skipping calling the callback when 1252when entering the B<execute> state and skipping calling the callback when
956entering the the B<result> state, but will leave the request otherwise 1253entering the the B<result> state, but will leave the request otherwise
957untouched. That means that requests that currently execute will not be 1254untouched (with the exception of readdir). That means that requests that
958stopped and resources held by the request will not be freed prematurely. 1255currently execute will not be stopped and resources held by the request
1256will not be freed prematurely.
959 1257
960=item cb $req $callback->(...) 1258=item cb $req $callback->(...)
961 1259
962Replace (or simply set) the callback registered to the request. 1260Replace (or simply set) the callback registered to the request.
963 1261
… …
1014Their lifetime, simplified, looks like this: when they are empty, they 1312Their lifetime, simplified, looks like this: when they are empty, they
1015will finish very quickly. If they contain only requests that are in the 1313will finish very quickly. If they contain only requests that are in the
1016C<done> state, they will also finish. Otherwise they will continue to 1314C<done> state, they will also finish. Otherwise they will continue to
1017exist. 1315exist.
1018 1316
1019That means after creating a group you have some time to add requests. And 1317That means after creating a group you have some time to add requests
1020in the callbacks of those requests, you can add further requests to the 1318(precisely before the callback has been invoked, which is only done within
1021group. And only when all those requests have finished will the the group 1319the C<poll_cb>). And in the callbacks of those requests, you can add
1022itself finish. 1320further requests to the group. And only when all those requests have
1321finished will the the group itself finish.
1023 1322
1024=over 4 1323=over 4
1025 1324
1026=item add $grp ... 1325=item add $grp ...
1027 1326
… …
1035 1334
1036=item $grp->cancel_subs 1335=item $grp->cancel_subs
1037 1336
1038Cancel all subrequests and clears any feeder, but not the group request 1337Cancel all subrequests and clears any feeder, but not the group request
1039itself. Useful when you queued a lot of events but got a result early. 1338itself. Useful when you queued a lot of events but got a result early.
1339
1340The group request will finish normally (you cannot add requests to the
1341group).
1040 1342
1041=item $grp->result (...) 1343=item $grp->result (...)
1042 1344
1043Set the result value(s) that will be passed to the group callback when all 1345Set the result value(s) that will be passed to the group callback when all
1044subrequests have finished and set the groups errno to the current value 1346subrequests have finished and set the groups errno to the current value
… …
1060=item feed $grp $callback->($grp) 1362=item feed $grp $callback->($grp)
1061 1363
1062Sets a feeder/generator on this group: every group can have an attached 1364Sets a feeder/generator on this group: every group can have an attached
1063generator that generates requests if idle. The idea behind this is that, 1365generator that generates requests if idle. The idea behind this is that,
1064although you could just queue as many requests as you want in a group, 1366although you could just queue as many requests as you want in a group,
1065this might starve other requests for a potentially long time. For 1367this might starve other requests for a potentially long time. For example,
1066example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1368C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1067requests, delaying any later requests for a long time. 1369delaying any later requests for a long time.
1068 1370
1069To avoid this, and allow incremental generation of requests, you can 1371To avoid this, and allow incremental generation of requests, you can
1070instead a group and set a feeder on it that generates those requests. The 1372instead a group and set a feeder on it that generates those requests. The
1071feed callback will be called whenever there are few enough (see C<limit>, 1373feed callback will be called whenever there are few enough (see C<limit>,
1072below) requests active in the group itself and is expected to queue more 1374below) requests active in the group itself and is expected to queue more
… …
1076not impose any limits). 1378not impose any limits).
1077 1379
1078If the feed does not queue more requests when called, it will be 1380If the feed does not queue more requests when called, it will be
1079automatically removed from the group. 1381automatically removed from the group.
1080 1382
1081If the feed limit is C<0>, it will be set to C<2> automatically. 1383If the feed limit is C<0> when this method is called, it will be set to
1384C<2> automatically.
1082 1385
1083Example: 1386Example:
1084 1387
1085 # stat all files in @files, but only ever use four aio requests concurrently: 1388 # stat all files in @files, but only ever use four aio requests concurrently:
1086 1389
… …
1098Sets the feeder limit for the group: The feeder will be called whenever 1401Sets the feeder limit for the group: The feeder will be called whenever
1099the group contains less than this many requests. 1402the group contains less than this many requests.
1100 1403
1101Setting the limit to C<0> will pause the feeding process. 1404Setting the limit to C<0> will pause the feeding process.
1102 1405
1406The default value for the limit is C<0>, but note that setting a feeder
1407automatically bumps it up to C<2>.
1408
1103=back 1409=back
1104 1410
1105=head2 SUPPORT FUNCTIONS 1411=head2 SUPPORT FUNCTIONS
1106 1412
1107=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1413=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1109=over 4 1415=over 4
1110 1416
1111=item $fileno = IO::AIO::poll_fileno 1417=item $fileno = IO::AIO::poll_fileno
1112 1418
1113Return the I<request result pipe file descriptor>. This filehandle must be 1419Return the I<request result pipe file descriptor>. This filehandle must be
1114polled for reading by some mechanism outside this module (e.g. Event or 1420polled for reading by some mechanism outside this module (e.g. EV, Glib,
1115select, see below or the SYNOPSIS). If the pipe becomes readable you have 1421select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1116to call C<poll_cb> to check the results. 1422you have to call C<poll_cb> to check the results.
1117 1423
1118See C<poll_cb> for an example. 1424See C<poll_cb> for an example.
1119 1425
1120=item IO::AIO::poll_cb 1426=item IO::AIO::poll_cb
1121 1427
1122Process some outstanding events on the result pipe. You have to call this 1428Process some outstanding events on the result pipe. You have to call
1123regularly. Returns the number of events processed. Returns immediately 1429this regularly. Returns C<0> if all events could be processed (or there
1124when no events are outstanding. The amount of events processed depends on 1430were no events to process), or C<-1> if it returned earlier for whatever
1125the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1431reason. Returns immediately when no events are outstanding. The amount of
1432events processed depends on the settings of C<IO::AIO::max_poll_req> and
1433C<IO::AIO::max_poll_time>.
1126 1434
1127If not all requests were processed for whatever reason, the filehandle 1435If not all requests were processed for whatever reason, the filehandle
1128will still be ready when C<poll_cb> returns. 1436will still be ready when C<poll_cb> returns, so normally you don't have to
1437do anything special to have it called later.
1438
1439Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1440ready, it can be beneficial to call this function from loops which submit
1441a lot of requests, to make sure the results get processed when they become
1442available and not just when the loop is finished and the event loop takes
1443over again. This function returns very fast when there are no outstanding
1444requests.
1129 1445
1130Example: Install an Event watcher that automatically calls 1446Example: Install an Event watcher that automatically calls
1131IO::AIO::poll_cb with high priority: 1447IO::AIO::poll_cb with high priority (more examples can be found in the
1448SYNOPSIS section, at the top of this document):
1132 1449
1133 Event->io (fd => IO::AIO::poll_fileno, 1450 Event->io (fd => IO::AIO::poll_fileno,
1134 poll => 'r', async => 1, 1451 poll => 'r', async => 1,
1135 cb => \&IO::AIO::poll_cb); 1452 cb => \&IO::AIO::poll_cb);
1453
1454=item IO::AIO::poll_wait
1455
1456If there are any outstanding requests and none of them in the result
1457phase, wait till the result filehandle becomes ready for reading (simply
1458does a C<select> on the filehandle. This is useful if you want to
1459synchronously wait for some requests to finish).
1460
1461See C<nreqs> for an example.
1462
1463=item IO::AIO::poll
1464
1465Waits until some requests have been handled.
1466
1467Returns the number of requests processed, but is otherwise strictly
1468equivalent to:
1469
1470 IO::AIO::poll_wait, IO::AIO::poll_cb
1471
1472=item IO::AIO::flush
1473
1474Wait till all outstanding AIO requests have been handled.
1475
1476Strictly equivalent to:
1477
1478 IO::AIO::poll_wait, IO::AIO::poll_cb
1479 while IO::AIO::nreqs;
1136 1480
1137=item IO::AIO::max_poll_reqs $nreqs 1481=item IO::AIO::max_poll_reqs $nreqs
1138 1482
1139=item IO::AIO::max_poll_time $seconds 1483=item IO::AIO::max_poll_time $seconds
1140 1484
… …
1165 # use a low priority so other tasks have priority 1509 # use a low priority so other tasks have priority
1166 Event->io (fd => IO::AIO::poll_fileno, 1510 Event->io (fd => IO::AIO::poll_fileno,
1167 poll => 'r', nice => 1, 1511 poll => 'r', nice => 1,
1168 cb => &IO::AIO::poll_cb); 1512 cb => &IO::AIO::poll_cb);
1169 1513
1170=item IO::AIO::poll_wait
1171
1172If there are any outstanding requests and none of them in the result
1173phase, wait till the result filehandle becomes ready for reading (simply
1174does a C<select> on the filehandle. This is useful if you want to
1175synchronously wait for some requests to finish).
1176
1177See C<nreqs> for an example.
1178
1179=item IO::AIO::poll
1180
1181Waits until some requests have been handled.
1182
1183Returns the number of requests processed, but is otherwise strictly
1184equivalent to:
1185
1186 IO::AIO::poll_wait, IO::AIO::poll_cb
1187
1188=item IO::AIO::flush
1189
1190Wait till all outstanding AIO requests have been handled.
1191
1192Strictly equivalent to:
1193
1194 IO::AIO::poll_wait, IO::AIO::poll_cb
1195 while IO::AIO::nreqs;
1196
1197=back 1514=back
1198 1515
1199=head3 CONTROLLING THE NUMBER OF THREADS 1516=head3 CONTROLLING THE NUMBER OF THREADS
1200 1517
1201=over 1518=over
… …
1234 1551
1235Under normal circumstances you don't need to call this function. 1552Under normal circumstances you don't need to call this function.
1236 1553
1237=item IO::AIO::max_idle $nthreads 1554=item IO::AIO::max_idle $nthreads
1238 1555
1239Limit the number of threads (default: 4) that are allowed to idle (i.e., 1556Limit the number of threads (default: 4) that are allowed to idle
1240threads that did not get a request to process within 10 seconds). That 1557(i.e., threads that did not get a request to process within the idle
1241means if a thread becomes idle while C<$nthreads> other threads are also 1558timeout (default: 10 seconds). That means if a thread becomes idle while
1242idle, it will free its resources and exit. 1559C<$nthreads> other threads are also idle, it will free its resources and
1560exit.
1243 1561
1244This is useful when you allow a large number of threads (e.g. 100 or 1000) 1562This is useful when you allow a large number of threads (e.g. 100 or 1000)
1245to allow for extremely high load situations, but want to free resources 1563to allow for extremely high load situations, but want to free resources
1246under normal circumstances (1000 threads can easily consume 30MB of RAM). 1564under normal circumstances (1000 threads can easily consume 30MB of RAM).
1247 1565
1248The default is probably ok in most situations, especially if thread 1566The default is probably ok in most situations, especially if thread
1249creation is fast. If thread creation is very slow on your system you might 1567creation is fast. If thread creation is very slow on your system you might
1250want to use larger values. 1568want to use larger values.
1251 1569
1570=item IO::AIO::idle_timeout $seconds
1571
1572Sets the minimum idle timeout (default 10) after which worker threads are
1573allowed to exit. SEe C<IO::AIO::max_idle>.
1574
1252=item IO::AIO::max_outstanding $maxreqs 1575=item IO::AIO::max_outstanding $maxreqs
1576
1577Sets the maximum number of outstanding requests to C<$nreqs>. If
1578you do queue up more than this number of requests, the next call to
1579C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1580C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1581longer exceeded.
1582
1583In other words, this setting does not enforce a queue limit, but can be
1584used to make poll functions block if the limit is exceeded.
1253 1585
1254This is a very bad function to use in interactive programs because it 1586This is a very bad function to use in interactive programs because it
1255blocks, and a bad way to reduce concurrency because it is inexact: Better 1587blocks, and a bad way to reduce concurrency because it is inexact: Better
1256use an C<aio_group> together with a feed callback. 1588use an C<aio_group> together with a feed callback.
1257 1589
1258Sets the maximum number of outstanding requests to C<$nreqs>. If you 1590It's main use is in scripts without an event loop - when you want to stat
1259do queue up more than this number of requests, the next call to the 1591a lot of files, you can write somehting like this:
1260C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1261function will block until the limit is no longer exceeded.
1262 1592
1263The default value is very large, so there is no practical limit on the 1593 IO::AIO::max_outstanding 32;
1264number of outstanding requests.
1265 1594
1266You can still queue as many requests as you want. Therefore, 1595 for my $path (...) {
1267C<max_outstanding> is mainly useful in simple scripts (with low values) or 1596 aio_stat $path , ...;
1268as a stop gap to shield against fatal memory overflow (with large values). 1597 IO::AIO::poll_cb;
1598 }
1599
1600 IO::AIO::flush;
1601
1602The call to C<poll_cb> inside the loop will normally return instantly, but
1603as soon as more thna C<32> reqeusts are in-flight, it will block until
1604some requests have been handled. This keeps the loop from pushing a large
1605number of C<aio_stat> requests onto the queue.
1606
1607The default value for C<max_outstanding> is very large, so there is no
1608practical limit on the number of outstanding requests.
1269 1609
1270=back 1610=back
1271 1611
1272=head3 STATISTICAL INFORMATION 1612=head3 STATISTICAL INFORMATION
1273 1613
… …
1293Returns the number of requests currently in the pending state (executed, 1633Returns the number of requests currently in the pending state (executed,
1294but not yet processed by poll_cb). 1634but not yet processed by poll_cb).
1295 1635
1296=back 1636=back
1297 1637
1638=head3 MISCELLANEOUS FUNCTIONS
1639
1640IO::AIO implements some functions that might be useful, but are not
1641asynchronous.
1642
1643=over 4
1644
1645=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1646
1647Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1648but is blocking (this makes most sense if you know the input data is
1649likely cached already and the output filehandle is set to non-blocking
1650operations).
1651
1652Returns the number of bytes copied, or C<-1> on error.
1653
1654=item IO::AIO::fadvise $fh, $offset, $len, $advice
1655
1656Simply calls the C<posix_fadvise> function (see its
1657manpage for details). The following advice constants are
1658avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1659C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1660C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1661
1662On systems that do not implement C<posix_fadvise>, this function returns
1663ENOSYS, otherwise the return value of C<posix_fadvise>.
1664
1665=item IO::AIO::madvise $scalar, $offset, $len, $advice
1666
1667Simply calls the C<posix_madvise> function (see its
1668manpage for details). The following advice constants are
1669avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1670C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1671
1672On systems that do not implement C<posix_madvise>, this function returns
1673ENOSYS, otherwise the return value of C<posix_madvise>.
1674
1675=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1676
1677Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1678$scalar (see its manpage for details). The following protect
1679constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1680C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1681
1682On systems that do not implement C<mprotect>, this function returns
1683ENOSYS, otherwise the return value of C<mprotect>.
1684
1685=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1686
1687Memory-maps a file (or anonymous memory range) and attaches it to the
1688given C<$scalar>, which will act like a string scalar.
1689
1690The only operations allowed on the scalar are C<substr>/C<vec> that don't
1691change the string length, and most read-only operations such as copying it
1692or searching it with regexes and so on.
1693
1694Anything else is unsafe and will, at best, result in memory leaks.
1695
1696The memory map associated with the C<$scalar> is automatically removed
1697when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1698C<IO::AIO::munmap> functions are called.
1699
1700This calls the C<mmap>(2) function internally. See your system's manual
1701page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1702
1703The C<$length> must be larger than zero and smaller than the actual
1704filesize.
1705
1706C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1707C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1708
1709C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1710C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1711not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1712(which is set to C<MAP_ANON> if your system only provides this
1713constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1714C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1715C<IO::AIO::MAP_NONBLOCK>
1716
1717If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1718
1719C<$offset> is the offset from the start of the file - it generally must be
1720a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1721
1722Example:
1723
1724 use Digest::MD5;
1725 use IO::AIO;
1726
1727 open my $fh, "<verybigfile"
1728 or die "$!";
1729
1730 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1731 or die "verybigfile: $!";
1732
1733 my $fast_md5 = md5 $data;
1734
1735=item IO::AIO::munmap $scalar
1736
1737Removes a previous mmap and undefines the C<$scalar>.
1738
1739=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1740
1741Calls the C<munlock> function, undoing the effects of a previous
1742C<aio_mlock> call (see its description for details).
1743
1744=item IO::AIO::munlockall
1745
1746Calls the C<munlockall> function.
1747
1748On systems that do not implement C<munlockall>, this function returns
1749ENOSYS, otherwise the return value of C<munlockall>.
1750
1751=back
1752
1298=cut 1753=cut
1299 1754
1300min_parallel 8; 1755min_parallel 8;
1301 1756
1302END { flush } 1757END { flush }
1303 1758
13041; 17591;
1305 1760
1761=head1 EVENT LOOP INTEGRATION
1762
1763It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1764automatically into many event loops:
1765
1766 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1767 use AnyEvent::AIO;
1768
1769You can also integrate IO::AIO manually into many event loops, here are
1770some examples of how to do this:
1771
1772 # EV integration
1773 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1774
1775 # Event integration
1776 Event->io (fd => IO::AIO::poll_fileno,
1777 poll => 'r',
1778 cb => \&IO::AIO::poll_cb);
1779
1780 # Glib/Gtk2 integration
1781 add_watch Glib::IO IO::AIO::poll_fileno,
1782 in => sub { IO::AIO::poll_cb; 1 };
1783
1784 # Tk integration
1785 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1786 readable => \&IO::AIO::poll_cb);
1787
1788 # Danga::Socket integration
1789 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1790 \&IO::AIO::poll_cb);
1791
1306=head2 FORK BEHAVIOUR 1792=head2 FORK BEHAVIOUR
1307 1793
1308This module should do "the right thing" when the process using it forks: 1794Usage of pthreads in a program changes the semantics of fork
1795considerably. Specifically, only async-safe functions can be called after
1796fork. Perl doesn't know about this, so in general, you cannot call fork
1797with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1798but many other extensions and (for inexplicable reasons) perl itself often
1799is linked against pthreads, so this limitation applies.
1309 1800
1310Before the fork, IO::AIO enters a quiescent state where no requests 1801Some operating systems have extensions that allow safe use of fork, and
1311can be added in other threads and no results will be processed. After 1802this module should do "the right thing" on those, and tries on others. At
1312the fork the parent simply leaves the quiescent state and continues 1803the time of this writing (2011) only GNU/Linux supports these extensions
1313request/result processing, while the child frees the request/result queue 1804to POSIX.
1314(so that the requests started before the fork will only be handled in the
1315parent). Threads will be started on demand until the limit set in the
1316parent process has been reached again.
1317
1318In short: the parent will, after a short pause, continue as if fork had
1319not been called, while the child will act as if IO::AIO has not been used
1320yet.
1321 1805
1322=head2 MEMORY USAGE 1806=head2 MEMORY USAGE
1323 1807
1324Per-request usage: 1808Per-request usage:
1325 1809
… …
1342 1826
1343Known bugs will be fixed in the next release. 1827Known bugs will be fixed in the next release.
1344 1828
1345=head1 SEE ALSO 1829=head1 SEE ALSO
1346 1830
1347L<Coro::AIO>. 1831L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1832more natural syntax.
1348 1833
1349=head1 AUTHOR 1834=head1 AUTHOR
1350 1835
1351 Marc Lehmann <schmorp@schmorp.de> 1836 Marc Lehmann <schmorp@schmorp.de>
1352 http://home.schmorp.de/ 1837 http://home.schmorp.de/

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