ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/IO-AIO/AIO.pm
(Generate patch)

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.124 by root, Sat May 10 19:25:33 2008 UTC vs.
Revision 1.201 by root, Tue Jul 5 09:24:11 2011 UTC

… …
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
… …
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
… …
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
… …
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;
… …
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.
… …
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 = '3.93';
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_realpath 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_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, $length = undef
275 IO::AIO::munlockall
222 276
223=head2 AIO REQUEST FUNCTIONS 277=head2 AIO REQUEST FUNCTIONS
224 278
225All the C<aio_*> calls are more or less thin wrappers around the syscall 279All the C<aio_*> calls are more or less thin wrappers around the syscall
226with the same name (sans C<aio_>). The arguments are similar or identical, 280with the same name (sans C<aio_>). The arguments are similar or identical,
227and they all accept an additional (and optional) C<$callback> argument 281and they all accept an additional (and optional) C<$callback> argument
228which 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
229the 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
230perl, which usually delivers "false") as it's sole argument when the given 284perl, which usually delivers "false") as its sole argument after the given
231syscall has been executed asynchronously. 285syscall has been executed asynchronously.
232 286
233All functions expecting a filehandle keep a copy of the filehandle 287All functions expecting a filehandle keep a copy of the filehandle
234internally until the request has finished. 288internally until the request has finished.
235 289
… …
249your 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
250environment, d) use Glib::filename_from_unicode on unicode filenames or e) 304environment, d) use Glib::filename_from_unicode on unicode filenames or e)
251use something else to ensure your scalar has the correct contents. 305use something else to ensure your scalar has the correct contents.
252 306
253This 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
254handles correctly wether it is set or not. 308handles correctly whether it is set or not.
255 309
256=over 4 310=over 4
257 311
258=item $prev_pri = aioreq_pri [$pri] 312=item $prev_pri = aioreq_pri [$pri]
259 313
… …
306by 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
307change the umask. 361change the umask.
308 362
309Example: 363Example:
310 364
311 aio_open "/etc/passwd", O_RDONLY, 0, sub { 365 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
312 if ($_[0]) { 366 if ($_[0]) {
313 print "open successful, fh is $_[0]\n"; 367 print "open successful, fh is $_[0]\n";
314 ... 368 ...
315 } else { 369 } else {
316 die "open failed: $!\n"; 370 die "open failed: $!\n";
317 } 371 }
318 }; 372 };
319 373
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
320 383
321=item aio_close $fh, $callback->($status) 384=item aio_close $fh, $callback->($status)
322 385
323Asynchronously close a file and call the callback with the result 386Asynchronously close a file and call the callback with the result
324code. 387code.
… …
337 400
338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 401=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
339 402
340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 403=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
341 404
342Reads 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<$fh> and
343into the scalar given by C<$data> and offset C<$dataoffset> and calls the 406C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
344callback 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
345like the syscall). 408error, just like the syscall).
409
410C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
411offset plus the actual number of bytes read.
346 412
347If C<$offset> is undefined, then the current file descriptor offset will 413If C<$offset> is undefined, then the current file descriptor offset will
348be used (and updated), otherwise the file descriptor offset will not be 414be used (and updated), otherwise the file descriptor offset will not be
349changed by these calls. 415changed by these calls.
350 416
351If C<$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<$data>.
352 419
353If C<$dataoffset> is less than zero, it will be counted from the end of 420If C<$dataoffset> is less than zero, it will be counted from the end of
354C<$data>. 421C<$data>.
355 422
356The C<$data> scalar I<MUST NOT> be modified in any way while the request 423The C<$data> scalar I<MUST NOT> be modified in any way while the request
… …
370 437
371Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 438Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
372reading at byte offset C<$in_offset>, and starts writing at the current 439reading at byte offset C<$in_offset>, and starts writing at the current
373file offset of C<$out_fh>. Because of that, it is not safe to issue more 440file offset of C<$out_fh>. Because of that, it is not safe to issue more
374than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 441than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
375other. 442other. The same C<$in_fh> works fine though, as this function does not
443move or use the file offset of C<$in_fh>.
376 444
445Please note that C<aio_sendfile> can read more bytes from C<$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
377This 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
378zero-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
379socket, and C<$in_fh> should refer to mmap'able file. 463a socket, and C<$in_fh> should refer to an mmap'able file.
380 464
381If 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>,
382emulated, 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
383regardless of the limitations of the operating system. 468type of filehandle regardless of the limitations of the operating system.
384 469
385Please note, however, that C<aio_sendfile> can read more bytes from 470As native sendfile syscalls (as practically any non-POSIX interface hacked
386C<$in_fh> than are written, and there is no way to find out how many 471together in a hurry to improve benchmark numbers) tend to be rather buggy
387bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 472on many systems, this implementation tries to work around some known bugs
388provides the number of bytes written to C<$out_fh>. Only if the result 473in Linux and FreeBSD kernels (probably others, too), but that might fail,
389value 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> -
390read. 475fewre bytes than expected might have been transferred.
391 476
392 477
393=item aio_readahead $fh,$offset,$length, $callback->($retval) 478=item aio_readahead $fh,$offset,$length, $callback->($retval)
394 479
395C<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
… …
418 503
419Currently, 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
420error 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
421unless perl itself is compiled with large file support. 506unless perl itself is compiled with large file support.
422 507
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
423Example: Print the length of F</etc/passwd>: 517Example: Print the length of F</etc/passwd>:
424 518
425 aio_stat "/etc/passwd", sub { 519 aio_stat "/etc/passwd", sub {
426 $_[0] and die "stat failed: $!"; 520 $_[0] and die "stat failed: $!";
427 print "size is ", -s _, "\n"; 521 print "size is ", -s _, "\n";
428 }; 522 };
429 523
430 524
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
431=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 570=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
432 571
433Works 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
434and $mtime being undef). Fractional times are supported if the underlying 573and $mtime being undef). Fractional times are supported if the underlying
435syscalls support them. 574syscalls support them.
… …
483 622
484The only (POSIX-) portable way of calling this function is: 623The only (POSIX-) portable way of calling this function is:
485 624
486 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 625 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
487 626
627See C<aio_stat> for info about some potentially helpful extra constants
628and functions.
488 629
489=item aio_link $srcpath, $dstpath, $callback->($status) 630=item aio_link $srcpath, $dstpath, $callback->($status)
490 631
491Asynchronously 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
492the path C<$dstpath> and call the callback with the result code. 633the path C<$dstpath> and call the callback with the result code.
… …
503Asynchronously read the symlink specified by C<$path> and pass it to 644Asynchronously read the symlink specified by C<$path> and pass it to
504the 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
505callback. 646callback.
506 647
507 648
649=item aio_realpath $path, $callback->($path)
650
651Asynchronously make the path absolute and resolve any symlinks in
652C<$path>. The resulting path only consists of directories.
653
654This request can be used to get the absolute path of the current working
655directory by passing it a path of F<.> (a single dot).
656
657
508=item aio_rename $srcpath, $dstpath, $callback->($status) 658=item aio_rename $srcpath, $dstpath, $callback->($status)
509 659
510Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 660Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
511rename(2) and call the callback with the result code. 661rename(2) and call the callback with the result code.
512 662
… …
528 678
529Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 679Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
530directory (i.e. opendir + readdir + closedir). The entries will not be 680directory (i.e. opendir + readdir + closedir). The entries will not be
531sorted, and will B<NOT> include the C<.> and C<..> entries. 681sorted, and will B<NOT> include the C<.> and C<..> entries.
532 682
533The callback a single argument which is either C<undef> or an array-ref 683The callback is passed a single argument which is either C<undef> or an
534with the filenames. 684array-ref with the filenames.
685
686
687=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
688
689Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
690behaviour and output format. In case of an error, C<$entries> will be
691C<undef>.
692
693The flags are a combination of the following constants, ORed together (the
694flags will also be passed to the callback, possibly modified):
695
696=over 4
697
698=item IO::AIO::READDIR_DENTS
699
700When this flag is off, then the callback gets an arrayref consisting of
701names only (as with C<aio_readdir>), otherwise it gets an arrayref with
702C<[$name, $type, $inode]> arrayrefs, each describing a single directory
703entry in more detail.
704
705C<$name> is the name of the entry.
706
707C<$type> is one of the C<IO::AIO::DT_xxx> constants:
708
709C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
710C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
711C<IO::AIO::DT_WHT>.
712
713C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
714know, you have to run stat yourself. Also, for speed reasons, the C<$type>
715scalars are read-only: you can not modify them.
716
717C<$inode> is the inode number (which might not be exact on systems with 64
718bit inode numbers and 32 bit perls). This field has unspecified content on
719systems that do not deliver the inode information.
720
721=item IO::AIO::READDIR_DIRS_FIRST
722
723When this flag is set, then the names will be returned in an order where
724likely directories come first, in optimal stat order. This is useful when
725you need to quickly find directories, or you want to find all directories
726while avoiding to stat() each entry.
727
728If the system returns type information in readdir, then this is used
729to find directories directly. Otherwise, likely directories are names
730beginning with ".", or otherwise names with no dots, of which names with
731short names are tried first.
732
733=item IO::AIO::READDIR_STAT_ORDER
734
735When this flag is set, then the names will be returned in an order
736suitable for stat()'ing each one. That is, when you plan to stat()
737all files in the given directory, then the returned order will likely
738be fastest.
739
740If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
741the likely dirs come first, resulting in a less optimal stat order.
742
743=item IO::AIO::READDIR_FOUND_UNKNOWN
744
745This flag should not be set when calling C<aio_readdirx>. Instead, it
746is being set by C<aio_readdirx>, when any of the C<$type>'s found were
747C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
748C<$type>'s are known, which can be used to speed up some algorithms.
749
750=back
535 751
536 752
537=item aio_load $path, $data, $callback->($status) 753=item aio_load $path, $data, $callback->($status)
538 754
539This is a composite request that tries to fully load the given file into 755This is a composite request that tries to fully load the given file into
… …
564 780
565=item aio_copy $srcpath, $dstpath, $callback->($status) 781=item aio_copy $srcpath, $dstpath, $callback->($status)
566 782
567Try to copy the I<file> (directories not supported as either source or 783Try to copy the I<file> (directories not supported as either source or
568destination) from C<$srcpath> to C<$dstpath> and call the callback with 784destination) from C<$srcpath> to C<$dstpath> and call the callback with
569the C<0> (error) or C<-1> ok. 785a status of C<0> (ok) or C<-1> (error, see C<$!>).
570 786
571This is a composite request that it creates the destination file with 787This is a composite request that creates the destination file with
572mode 0200 and copies the contents of the source file into it using 788mode 0200 and copies the contents of the source file into it using
573C<aio_sendfile>, followed by restoring atime, mtime, access mode and 789C<aio_sendfile>, followed by restoring atime, mtime, access mode and
574uid/gid, in that order. 790uid/gid, in that order.
575 791
576If an error occurs, the partial destination file will be unlinked, if 792If an error occurs, the partial destination file will be unlinked, if
… …
586 my $grp = aio_group $cb; 802 my $grp = aio_group $cb;
587 803
588 aioreq_pri $pri; 804 aioreq_pri $pri;
589 add $grp aio_open $src, O_RDONLY, 0, sub { 805 add $grp aio_open $src, O_RDONLY, 0, sub {
590 if (my $src_fh = $_[0]) { 806 if (my $src_fh = $_[0]) {
591 my @stat = stat $src_fh; 807 my @stat = stat $src_fh; # hmm, might block over nfs?
592 808
593 aioreq_pri $pri; 809 aioreq_pri $pri;
594 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 810 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
595 if (my $dst_fh = $_[0]) { 811 if (my $dst_fh = $_[0]) {
596 aioreq_pri $pri; 812 aioreq_pri $pri;
597 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 813 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
598 if ($_[0] == $stat[7]) { 814 if ($_[0] == $stat[7]) {
599 $grp->result (0); 815 $grp->result (0);
600 close $src_fh; 816 close $src_fh;
601 817
602 # those should not normally block. should. should. 818 my $ch = sub {
603 utime $stat[8], $stat[9], $dst; 819 aioreq_pri $pri;
604 chmod $stat[2] & 07777, $dst_fh; 820 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
605 chown $stat[4], $stat[5], $dst_fh; 821 aioreq_pri $pri;
822 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
823 aioreq_pri $pri;
824 add $grp aio_close $dst_fh;
825 }
826 };
827 };
606 828
607 aioreq_pri $pri; 829 aioreq_pri $pri;
608 add $grp aio_close $dst_fh; 830 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
831 if ($_[0] < 0 && $! == ENOSYS) {
832 aioreq_pri $pri;
833 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
834 } else {
835 $ch->();
836 }
837 };
609 } else { 838 } else {
610 $grp->result (-1); 839 $grp->result (-1);
611 close $src_fh; 840 close $src_fh;
612 close $dst_fh; 841 close $dst_fh;
613 842
… …
630 859
631=item aio_move $srcpath, $dstpath, $callback->($status) 860=item aio_move $srcpath, $dstpath, $callback->($status)
632 861
633Try to move the I<file> (directories not supported as either source or 862Try to move the I<file> (directories not supported as either source or
634destination) from C<$srcpath> to C<$dstpath> and call the callback with 863destination) from C<$srcpath> to C<$dstpath> and call the callback with
635the C<0> (error) or C<-1> ok. 864a status of C<0> (ok) or C<-1> (error, see C<$!>).
636 865
637This is a composite request that tries to rename(2) the file first. If 866This is a composite request that tries to rename(2) the file first; if
638rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 867rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
639that is successful, unlinking the C<$srcpath>. 868that is successful, unlinks the C<$srcpath>.
640 869
641=cut 870=cut
642 871
643sub aio_move($$;$) { 872sub aio_move($$;$) {
644 my ($src, $dst, $cb) = @_; 873 my ($src, $dst, $cb) = @_;
… …
651 if ($_[0] && $! == EXDEV) { 880 if ($_[0] && $! == EXDEV) {
652 aioreq_pri $pri; 881 aioreq_pri $pri;
653 add $grp aio_copy $src, $dst, sub { 882 add $grp aio_copy $src, $dst, sub {
654 $grp->result ($_[0]); 883 $grp->result ($_[0]);
655 884
656 if (!$_[0]) { 885 unless ($_[0]) {
657 aioreq_pri $pri; 886 aioreq_pri $pri;
658 add $grp aio_unlink $src; 887 add $grp aio_unlink $src;
659 } 888 }
660 }; 889 };
661 } else { 890 } else {
… …
691 920
692Implementation notes. 921Implementation notes.
693 922
694The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 923The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
695 924
925If readdir returns file type information, then this is used directly to
926find directories.
927
696After reading the directory, the modification time, size etc. of the 928Otherwise, after reading the directory, the modification time, size etc.
697directory before and after the readdir is checked, and if they match (and 929of the directory before and after the readdir is checked, and if they
698isn't the current time), the link count will be used to decide how many 930match (and isn't the current time), the link count will be used to decide
699entries are directories (if >= 2). Otherwise, no knowledge of the number 931how many entries are directories (if >= 2). Otherwise, no knowledge of the
700of subdirectories will be assumed. 932number of subdirectories will be assumed.
701 933
702Then entries will be sorted into likely directories (everything without 934Then entries will be sorted into likely directories a non-initial dot
703a non-initial dot currently) and likely non-directories (everything 935currently) and likely non-directories (see C<aio_readdirx>). Then every
704else). Then every entry plus an appended C</.> will be C<stat>'ed, 936entry plus an appended C</.> will be C<stat>'ed, likely directories first,
705likely directories first. If that succeeds, it assumes that the entry 937in order of their inode numbers. If that succeeds, it assumes that the
706is a directory or a symlink to directory (which will be checked 938entry is a directory or a symlink to directory (which will be checked
707seperately). This is often faster than stat'ing the entry itself because 939seperately). This is often faster than stat'ing the entry itself because
708filesystems might detect the type of the entry without reading the inode 940filesystems might detect the type of the entry without reading the inode
709data (e.g. ext2fs filetype feature). 941data (e.g. ext2fs filetype feature), even on systems that cannot return
942the filetype information on readdir.
710 943
711If the known number of directories (link count - 2) has been reached, the 944If the known number of directories (link count - 2) has been reached, the
712rest of the entries is assumed to be non-directories. 945rest of the entries is assumed to be non-directories.
713 946
714This only works with certainty on POSIX (= UNIX) filesystems, which 947This only works with certainty on POSIX (= UNIX) filesystems, which
… …
736 my $now = time; 969 my $now = time;
737 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 970 my $hash1 = join ":", (stat _)[0,1,3,7,9];
738 971
739 # read the directory entries 972 # read the directory entries
740 aioreq_pri $pri; 973 aioreq_pri $pri;
741 add $grp aio_readdir $path, sub { 974 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
742 my $entries = shift 975 my $entries = shift
743 or return $grp->result (); 976 or return $grp->result ();
744 977
745 # stat the dir another time 978 # stat the dir another time
746 aioreq_pri $pri; 979 aioreq_pri $pri;
… …
752 # take the slow route if anything looks fishy 985 # take the slow route if anything looks fishy
753 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 986 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
754 $ndirs = -1; 987 $ndirs = -1;
755 } else { 988 } else {
756 # if nlink == 2, we are finished 989 # if nlink == 2, we are finished
757 # on non-posix-fs's, we rely on nlink < 2 990 # for non-posix-fs's, we rely on nlink < 2
758 $ndirs = (stat _)[3] - 2 991 $ndirs = (stat _)[3] - 2
759 or return $grp->result ([], $entries); 992 or return $grp->result ([], $entries);
760 } 993 }
761 994
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); 995 my (@dirs, @nondirs);
770 996
771 my $statgrp = add $grp aio_group sub { 997 my $statgrp = add $grp aio_group sub {
772 $grp->result (\@dirs, \@nondirs); 998 $grp->result (\@dirs, \@nondirs);
773 }; 999 };
774 1000
775 limit $statgrp $maxreq; 1001 limit $statgrp $maxreq;
776 feed $statgrp sub { 1002 feed $statgrp sub {
777 return unless @$entries; 1003 return unless @$entries;
778 my $entry = pop @$entries; 1004 my $entry = shift @$entries;
779 1005
780 aioreq_pri $pri; 1006 aioreq_pri $pri;
781 add $statgrp aio_stat "$path/$entry/.", sub { 1007 add $statgrp aio_stat "$path/$entry/.", sub {
782 if ($_[0] < 0) { 1008 if ($_[0] < 0) {
783 push @nondirs, $entry; 1009 push @nondirs, $entry;
… …
856callback with the fdatasync result code. 1082callback with the fdatasync result code.
857 1083
858If this call isn't available because your OS lacks it or it couldn't be 1084If this call isn't available because your OS lacks it or it couldn't be
859detected, it will be emulated by calling C<fsync> instead. 1085detected, it will be emulated by calling C<fsync> instead.
860 1086
1087=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1088
1089Sync the data portion of the file specified by C<$offset> and C<$length>
1090to disk (but NOT the metadata), by calling the Linux-specific
1091sync_file_range call. If sync_file_range is not available or it returns
1092ENOSYS, then fdatasync or fsync is being substituted.
1093
1094C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1095C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1096C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1097manpage for details.
1098
861=item aio_pathsync $path, $callback->($status) 1099=item aio_pathsync $path, $callback->($status)
862 1100
863This request tries to open, fsync and close the given path. This is a 1101This request tries to open, fsync and close the given path. This is a
864composite request intended tosync directories after directory operations 1102composite request intended to sync directories after directory operations
865(E.g. rename). This might not work on all operating systems or have any 1103(E.g. rename). This might not work on all operating systems or have any
866specific effect, but usually it makes sure that directory changes get 1104specific effect, but usually it makes sure that directory changes get
867written to disc. It works for anything that can be opened for read-only, 1105written to disc. It works for anything that can be opened for read-only,
868not just directories. 1106not just directories.
1107
1108Future versions of this function might fall back to other methods when
1109C<fsync> on the directory fails (such as calling C<sync>).
869 1110
870Passes C<0> when everything went ok, and C<-1> on error. 1111Passes C<0> when everything went ok, and C<-1> on error.
871 1112
872=cut 1113=cut
873 1114
… …
894 }; 1135 };
895 1136
896 $grp 1137 $grp
897} 1138}
898 1139
1140=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1141
1142This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1143scalars (see the C<IO::AIO::mmap> function, although it also works on data
1144scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1145scalar must only be modified in-place while an aio operation is pending on
1146it).
1147
1148It calls the C<msync> function of your OS, if available, with the memory
1149area starting at C<$offset> in the string and ending C<$length> bytes
1150later. If C<$length> is negative, counts from the end, and if C<$length>
1151is C<undef>, then it goes till the end of the string. The flags can be
1152a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1153C<IO::AIO::MS_SYNC>.
1154
1155=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1156
1157This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1158scalars.
1159
1160It touches (reads or writes) all memory pages in the specified
1161range inside the scalar. All caveats and parameters are the same
1162as for C<aio_msync>, above, except for flags, which must be either
1163C<0> (which reads all pages and ensures they are instantiated) or
1164C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1165writing an octet from it, which dirties the page).
1166
1167=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1168
1169This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170scalars.
1171
1172It reads in all the pages of the underlying storage into memory (if any)
1173and locks them, so they are not getting swapped/paged out or removed.
1174
1175If C<$length> is undefined, then the scalar will be locked till the end.
1176
1177On systems that do not implement C<mlock>, this function returns C<-1>
1178and sets errno to C<ENOSYS>.
1179
1180Note that the corresponding C<munlock> is synchronous and is
1181documented under L<MISCELLANEOUS FUNCTIONS>.
1182
1183Example: open a file, mmap and mlock it - both will be undone when
1184C<$data> gets destroyed.
1185
1186 open my $fh, "<", $path or die "$path: $!";
1187 my $data;
1188 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1189 aio_mlock $data; # mlock in background
1190
1191=item aio_mlockall $flags, $callback->($status)
1192
1193Calls the C<mlockall> function with the given C<$flags> (a combination of
1194C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1195
1196On systems that do not implement C<mlockall>, this function returns C<-1>
1197and sets errno to C<ENOSYS>.
1198
1199Note that the corresponding C<munlockall> is synchronous and is
1200documented under L<MISCELLANEOUS FUNCTIONS>.
1201
1202Example: asynchronously lock all current and future pages into memory.
1203
1204 aio_mlockall IO::AIO::MCL_FUTURE;
1205
899=item aio_group $callback->(...) 1206=item aio_group $callback->(...)
900 1207
901This is a very special aio request: Instead of doing something, it is a 1208This is a very special aio request: Instead of doing something, it is a
902container for other aio requests, which is useful if you want to bundle 1209container for other aio requests, which is useful if you want to bundle
903many requests into a single, composite, request with a definite callback 1210many requests into a single, composite, request with a definite callback
… …
952=item cancel $req 1259=item cancel $req
953 1260
954Cancels the request, if possible. Has the effect of skipping execution 1261Cancels the request, if possible. Has the effect of skipping execution
955when entering the B<execute> state and skipping calling the callback when 1262when entering the B<execute> state and skipping calling the callback when
956entering the the B<result> state, but will leave the request otherwise 1263entering the the B<result> state, but will leave the request otherwise
957untouched. That means that requests that currently execute will not be 1264untouched (with the exception of readdir). That means that requests that
958stopped and resources held by the request will not be freed prematurely. 1265currently execute will not be stopped and resources held by the request
1266will not be freed prematurely.
959 1267
960=item cb $req $callback->(...) 1268=item cb $req $callback->(...)
961 1269
962Replace (or simply set) the callback registered to the request. 1270Replace (or simply set) the callback registered to the request.
963 1271
… …
1014Their lifetime, simplified, looks like this: when they are empty, they 1322Their lifetime, simplified, looks like this: when they are empty, they
1015will finish very quickly. If they contain only requests that are in the 1323will finish very quickly. If they contain only requests that are in the
1016C<done> state, they will also finish. Otherwise they will continue to 1324C<done> state, they will also finish. Otherwise they will continue to
1017exist. 1325exist.
1018 1326
1019That means after creating a group you have some time to add requests. And 1327That means after creating a group you have some time to add requests
1020in the callbacks of those requests, you can add further requests to the 1328(precisely before the callback has been invoked, which is only done within
1021group. And only when all those requests have finished will the the group 1329the C<poll_cb>). And in the callbacks of those requests, you can add
1022itself finish. 1330further requests to the group. And only when all those requests have
1331finished will the the group itself finish.
1023 1332
1024=over 4 1333=over 4
1025 1334
1026=item add $grp ... 1335=item add $grp ...
1027 1336
… …
1035 1344
1036=item $grp->cancel_subs 1345=item $grp->cancel_subs
1037 1346
1038Cancel all subrequests and clears any feeder, but not the group request 1347Cancel 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. 1348itself. Useful when you queued a lot of events but got a result early.
1349
1350The group request will finish normally (you cannot add requests to the
1351group).
1040 1352
1041=item $grp->result (...) 1353=item $grp->result (...)
1042 1354
1043Set the result value(s) that will be passed to the group callback when all 1355Set the result value(s) that will be passed to the group callback when all
1044subrequests have finished and set the groups errno to the current value 1356subrequests have finished and set the groups errno to the current value
… …
1060=item feed $grp $callback->($grp) 1372=item feed $grp $callback->($grp)
1061 1373
1062Sets a feeder/generator on this group: every group can have an attached 1374Sets a feeder/generator on this group: every group can have an attached
1063generator that generates requests if idle. The idea behind this is that, 1375generator 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, 1376although you could just queue as many requests as you want in a group,
1065this might starve other requests for a potentially long time. For 1377this might starve other requests for a potentially long time. For example,
1066example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1378C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1067requests, delaying any later requests for a long time. 1379delaying any later requests for a long time.
1068 1380
1069To avoid this, and allow incremental generation of requests, you can 1381To avoid this, and allow incremental generation of requests, you can
1070instead a group and set a feeder on it that generates those requests. The 1382instead a group and set a feeder on it that generates those requests. The
1071feed callback will be called whenever there are few enough (see C<limit>, 1383feed callback will be called whenever there are few enough (see C<limit>,
1072below) requests active in the group itself and is expected to queue more 1384below) requests active in the group itself and is expected to queue more
… …
1076not impose any limits). 1388not impose any limits).
1077 1389
1078If the feed does not queue more requests when called, it will be 1390If the feed does not queue more requests when called, it will be
1079automatically removed from the group. 1391automatically removed from the group.
1080 1392
1081If the feed limit is C<0>, it will be set to C<2> automatically. 1393If the feed limit is C<0> when this method is called, it will be set to
1394C<2> automatically.
1082 1395
1083Example: 1396Example:
1084 1397
1085 # stat all files in @files, but only ever use four aio requests concurrently: 1398 # stat all files in @files, but only ever use four aio requests concurrently:
1086 1399
… …
1098Sets the feeder limit for the group: The feeder will be called whenever 1411Sets the feeder limit for the group: The feeder will be called whenever
1099the group contains less than this many requests. 1412the group contains less than this many requests.
1100 1413
1101Setting the limit to C<0> will pause the feeding process. 1414Setting the limit to C<0> will pause the feeding process.
1102 1415
1416The default value for the limit is C<0>, but note that setting a feeder
1417automatically bumps it up to C<2>.
1418
1103=back 1419=back
1104 1420
1105=head2 SUPPORT FUNCTIONS 1421=head2 SUPPORT FUNCTIONS
1106 1422
1107=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1423=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1109=over 4 1425=over 4
1110 1426
1111=item $fileno = IO::AIO::poll_fileno 1427=item $fileno = IO::AIO::poll_fileno
1112 1428
1113Return the I<request result pipe file descriptor>. This filehandle must be 1429Return the I<request result pipe file descriptor>. This filehandle must be
1114polled for reading by some mechanism outside this module (e.g. Event or 1430polled for reading by some mechanism outside this module (e.g. EV, Glib,
1115select, see below or the SYNOPSIS). If the pipe becomes readable you have 1431select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1116to call C<poll_cb> to check the results. 1432you have to call C<poll_cb> to check the results.
1117 1433
1118See C<poll_cb> for an example. 1434See C<poll_cb> for an example.
1119 1435
1120=item IO::AIO::poll_cb 1436=item IO::AIO::poll_cb
1121 1437
1122Process some outstanding events on the result pipe. You have to call this 1438Process some outstanding events on the result pipe. You have to call
1123regularly. Returns the number of events processed. Returns immediately 1439this regularly. Returns C<0> if all events could be processed (or there
1124when no events are outstanding. The amount of events processed depends on 1440were no events to process), or C<-1> if it returned earlier for whatever
1125the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1441reason. Returns immediately when no events are outstanding. The amount of
1442events processed depends on the settings of C<IO::AIO::max_poll_req> and
1443C<IO::AIO::max_poll_time>.
1126 1444
1127If not all requests were processed for whatever reason, the filehandle 1445If not all requests were processed for whatever reason, the filehandle
1128will still be ready when C<poll_cb> returns. 1446will still be ready when C<poll_cb> returns, so normally you don't have to
1447do anything special to have it called later.
1448
1449Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1450ready, it can be beneficial to call this function from loops which submit
1451a lot of requests, to make sure the results get processed when they become
1452available and not just when the loop is finished and the event loop takes
1453over again. This function returns very fast when there are no outstanding
1454requests.
1129 1455
1130Example: Install an Event watcher that automatically calls 1456Example: Install an Event watcher that automatically calls
1131IO::AIO::poll_cb with high priority: 1457IO::AIO::poll_cb with high priority (more examples can be found in the
1458SYNOPSIS section, at the top of this document):
1132 1459
1133 Event->io (fd => IO::AIO::poll_fileno, 1460 Event->io (fd => IO::AIO::poll_fileno,
1134 poll => 'r', async => 1, 1461 poll => 'r', async => 1,
1135 cb => \&IO::AIO::poll_cb); 1462 cb => \&IO::AIO::poll_cb);
1463
1464=item IO::AIO::poll_wait
1465
1466If there are any outstanding requests and none of them in the result
1467phase, wait till the result filehandle becomes ready for reading (simply
1468does a C<select> on the filehandle. This is useful if you want to
1469synchronously wait for some requests to finish).
1470
1471See C<nreqs> for an example.
1472
1473=item IO::AIO::poll
1474
1475Waits until some requests have been handled.
1476
1477Returns the number of requests processed, but is otherwise strictly
1478equivalent to:
1479
1480 IO::AIO::poll_wait, IO::AIO::poll_cb
1481
1482=item IO::AIO::flush
1483
1484Wait till all outstanding AIO requests have been handled.
1485
1486Strictly equivalent to:
1487
1488 IO::AIO::poll_wait, IO::AIO::poll_cb
1489 while IO::AIO::nreqs;
1136 1490
1137=item IO::AIO::max_poll_reqs $nreqs 1491=item IO::AIO::max_poll_reqs $nreqs
1138 1492
1139=item IO::AIO::max_poll_time $seconds 1493=item IO::AIO::max_poll_time $seconds
1140 1494
… …
1165 # use a low priority so other tasks have priority 1519 # use a low priority so other tasks have priority
1166 Event->io (fd => IO::AIO::poll_fileno, 1520 Event->io (fd => IO::AIO::poll_fileno,
1167 poll => 'r', nice => 1, 1521 poll => 'r', nice => 1,
1168 cb => &IO::AIO::poll_cb); 1522 cb => &IO::AIO::poll_cb);
1169 1523
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 1524=back
1198 1525
1199=head3 CONTROLLING THE NUMBER OF THREADS 1526=head3 CONTROLLING THE NUMBER OF THREADS
1200 1527
1201=over 1528=over
… …
1234 1561
1235Under normal circumstances you don't need to call this function. 1562Under normal circumstances you don't need to call this function.
1236 1563
1237=item IO::AIO::max_idle $nthreads 1564=item IO::AIO::max_idle $nthreads
1238 1565
1239Limit the number of threads (default: 4) that are allowed to idle (i.e., 1566Limit the number of threads (default: 4) that are allowed to idle
1240threads that did not get a request to process within 10 seconds). That 1567(i.e., threads that did not get a request to process within the idle
1241means if a thread becomes idle while C<$nthreads> other threads are also 1568timeout (default: 10 seconds). That means if a thread becomes idle while
1242idle, it will free its resources and exit. 1569C<$nthreads> other threads are also idle, it will free its resources and
1570exit.
1243 1571
1244This is useful when you allow a large number of threads (e.g. 100 or 1000) 1572This is useful when you allow a large number of threads (e.g. 100 or 1000)
1245to allow for extremely high load situations, but want to free resources 1573to allow for extremely high load situations, but want to free resources
1246under normal circumstances (1000 threads can easily consume 30MB of RAM). 1574under normal circumstances (1000 threads can easily consume 30MB of RAM).
1247 1575
1248The default is probably ok in most situations, especially if thread 1576The default is probably ok in most situations, especially if thread
1249creation is fast. If thread creation is very slow on your system you might 1577creation is fast. If thread creation is very slow on your system you might
1250want to use larger values. 1578want to use larger values.
1251 1579
1580=item IO::AIO::idle_timeout $seconds
1581
1582Sets the minimum idle timeout (default 10) after which worker threads are
1583allowed to exit. SEe C<IO::AIO::max_idle>.
1584
1252=item IO::AIO::max_outstanding $maxreqs 1585=item IO::AIO::max_outstanding $maxreqs
1586
1587Sets the maximum number of outstanding requests to C<$nreqs>. If
1588you do queue up more than this number of requests, the next call to
1589C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1590C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1591longer exceeded.
1592
1593In other words, this setting does not enforce a queue limit, but can be
1594used to make poll functions block if the limit is exceeded.
1253 1595
1254This is a very bad function to use in interactive programs because it 1596This is a very bad function to use in interactive programs because it
1255blocks, and a bad way to reduce concurrency because it is inexact: Better 1597blocks, and a bad way to reduce concurrency because it is inexact: Better
1256use an C<aio_group> together with a feed callback. 1598use an C<aio_group> together with a feed callback.
1257 1599
1258Sets the maximum number of outstanding requests to C<$nreqs>. If you 1600It's main use is in scripts without an event loop - when you want to stat
1259do queue up more than this number of requests, the next call to the 1601a 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 1602
1263The default value is very large, so there is no practical limit on the 1603 IO::AIO::max_outstanding 32;
1264number of outstanding requests.
1265 1604
1266You can still queue as many requests as you want. Therefore, 1605 for my $path (...) {
1267C<max_outstanding> is mainly useful in simple scripts (with low values) or 1606 aio_stat $path , ...;
1268as a stop gap to shield against fatal memory overflow (with large values). 1607 IO::AIO::poll_cb;
1608 }
1609
1610 IO::AIO::flush;
1611
1612The call to C<poll_cb> inside the loop will normally return instantly, but
1613as soon as more thna C<32> reqeusts are in-flight, it will block until
1614some requests have been handled. This keeps the loop from pushing a large
1615number of C<aio_stat> requests onto the queue.
1616
1617The default value for C<max_outstanding> is very large, so there is no
1618practical limit on the number of outstanding requests.
1269 1619
1270=back 1620=back
1271 1621
1272=head3 STATISTICAL INFORMATION 1622=head3 STATISTICAL INFORMATION
1273 1623
… …
1293Returns the number of requests currently in the pending state (executed, 1643Returns the number of requests currently in the pending state (executed,
1294but not yet processed by poll_cb). 1644but not yet processed by poll_cb).
1295 1645
1296=back 1646=back
1297 1647
1648=head3 MISCELLANEOUS FUNCTIONS
1649
1650IO::AIO implements some functions that might be useful, but are not
1651asynchronous.
1652
1653=over 4
1654
1655=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1656
1657Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1658but is blocking (this makes most sense if you know the input data is
1659likely cached already and the output filehandle is set to non-blocking
1660operations).
1661
1662Returns the number of bytes copied, or C<-1> on error.
1663
1664=item IO::AIO::fadvise $fh, $offset, $len, $advice
1665
1666Simply calls the C<posix_fadvise> function (see its
1667manpage for details). The following advice constants are
1668avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1669C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1670C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1671
1672On systems that do not implement C<posix_fadvise>, this function returns
1673ENOSYS, otherwise the return value of C<posix_fadvise>.
1674
1675=item IO::AIO::madvise $scalar, $offset, $len, $advice
1676
1677Simply calls the C<posix_madvise> function (see its
1678manpage for details). The following advice constants are
1679avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1680C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1681
1682On systems that do not implement C<posix_madvise>, this function returns
1683ENOSYS, otherwise the return value of C<posix_madvise>.
1684
1685=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1686
1687Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1688$scalar (see its manpage for details). The following protect
1689constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1690C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1691
1692On systems that do not implement C<mprotect>, this function returns
1693ENOSYS, otherwise the return value of C<mprotect>.
1694
1695=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1696
1697Memory-maps a file (or anonymous memory range) and attaches it to the
1698given C<$scalar>, which will act like a string scalar.
1699
1700The only operations allowed on the scalar are C<substr>/C<vec> that don't
1701change the string length, and most read-only operations such as copying it
1702or searching it with regexes and so on.
1703
1704Anything else is unsafe and will, at best, result in memory leaks.
1705
1706The memory map associated with the C<$scalar> is automatically removed
1707when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1708C<IO::AIO::munmap> functions are called.
1709
1710This calls the C<mmap>(2) function internally. See your system's manual
1711page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1712
1713The C<$length> must be larger than zero and smaller than the actual
1714filesize.
1715
1716C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1717C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1718
1719C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1720C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1721not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1722(which is set to C<MAP_ANON> if your system only provides this
1723constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1724C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1725C<IO::AIO::MAP_NONBLOCK>
1726
1727If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1728
1729C<$offset> is the offset from the start of the file - it generally must be
1730a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1731
1732Example:
1733
1734 use Digest::MD5;
1735 use IO::AIO;
1736
1737 open my $fh, "<verybigfile"
1738 or die "$!";
1739
1740 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1741 or die "verybigfile: $!";
1742
1743 my $fast_md5 = md5 $data;
1744
1745=item IO::AIO::munmap $scalar
1746
1747Removes a previous mmap and undefines the C<$scalar>.
1748
1749=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1750
1751Calls the C<munlock> function, undoing the effects of a previous
1752C<aio_mlock> call (see its description for details).
1753
1754=item IO::AIO::munlockall
1755
1756Calls the C<munlockall> function.
1757
1758On systems that do not implement C<munlockall>, this function returns
1759ENOSYS, otherwise the return value of C<munlockall>.
1760
1761=back
1762
1298=cut 1763=cut
1299 1764
1300min_parallel 8; 1765min_parallel 8;
1301 1766
1302END { flush } 1767END { flush }
1303 1768
13041; 17691;
1305 1770
1771=head1 EVENT LOOP INTEGRATION
1772
1773It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1774automatically into many event loops:
1775
1776 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1777 use AnyEvent::AIO;
1778
1779You can also integrate IO::AIO manually into many event loops, here are
1780some examples of how to do this:
1781
1782 # EV integration
1783 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1784
1785 # Event integration
1786 Event->io (fd => IO::AIO::poll_fileno,
1787 poll => 'r',
1788 cb => \&IO::AIO::poll_cb);
1789
1790 # Glib/Gtk2 integration
1791 add_watch Glib::IO IO::AIO::poll_fileno,
1792 in => sub { IO::AIO::poll_cb; 1 };
1793
1794 # Tk integration
1795 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1796 readable => \&IO::AIO::poll_cb);
1797
1798 # Danga::Socket integration
1799 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1800 \&IO::AIO::poll_cb);
1801
1306=head2 FORK BEHAVIOUR 1802=head2 FORK BEHAVIOUR
1307 1803
1308This module should do "the right thing" when the process using it forks: 1804Usage of pthreads in a program changes the semantics of fork
1805considerably. Specifically, only async-safe functions can be called after
1806fork. Perl doesn't know about this, so in general, you cannot call fork
1807with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1808but many other extensions and (for inexplicable reasons) perl itself often
1809is linked against pthreads, so this limitation applies.
1309 1810
1310Before the fork, IO::AIO enters a quiescent state where no requests 1811Some operating systems have extensions that allow safe use of fork, and
1311can be added in other threads and no results will be processed. After 1812this module should do "the right thing" on those, and tries on others. At
1312the fork the parent simply leaves the quiescent state and continues 1813the time of this writing (2011) only GNU/Linux supports these extensions
1313request/result processing, while the child frees the request/result queue 1814to 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 1815
1322=head2 MEMORY USAGE 1816=head2 MEMORY USAGE
1323 1817
1324Per-request usage: 1818Per-request usage:
1325 1819
… …
1342 1836
1343Known bugs will be fixed in the next release. 1837Known bugs will be fixed in the next release.
1344 1838
1345=head1 SEE ALSO 1839=head1 SEE ALSO
1346 1840
1347L<Coro::AIO>. 1841L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1842more natural syntax.
1348 1843
1349=head1 AUTHOR 1844=head1 AUTHOR
1350 1845
1351 Marc Lehmann <schmorp@schmorp.de> 1846 Marc Lehmann <schmorp@schmorp.de>
1352 http://home.schmorp.de/ 1847 http://home.schmorp.de/

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines