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Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC vs.
Revision 1.135 by root, Tue Sep 30 03:50:59 2008 UTC

… …
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", O_RDONLY, 0, sub {
10 my ($fh) = @_; 10 my $fh = shift
11 or die "/etc/passwd: $!";
11 ... 12 ...
12 }; 13 };
13 14
14 aio_unlink "/tmp/file", sub { }; 15 aio_unlink "/tmp/file", sub { };
15 16
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25 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
26 27
27 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
28 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
29 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
30 # AnyEvent integration 34 # EV integration
31 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 35 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
32 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33 36
34 # Event integration 37 # Event integration
35 Event->io (fd => IO::AIO::poll_fileno, 38 Event->io (fd => IO::AIO::poll_fileno,
36 poll => 'r', 39 poll => 'r',
37 cb => \&IO::AIO::poll_cb); 40 cb => \&IO::AIO::poll_cb);
… …
50 53
51=head1 DESCRIPTION 54=head1 DESCRIPTION
52 55
53This module implements asynchronous I/O using whatever means your 56This module implements asynchronous I/O using whatever means your
54operating system supports. 57operating system supports.
58
59Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even
63when doing heavy I/O (GUI programs, high performance network servers
64etc.), but can also be used to easily do operations in parallel that are
65normally done sequentially, e.g. stat'ing many files, which is much faster
66on a RAID volume or over NFS when you do a number of stat operations
67concurrently.
68
69While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very
72inefficient. Use an event loop for that (such as the L<Event|Event>
73module): IO::AIO will naturally fit into such an event loop itself.
55 74
56In this version, a number of threads are started that execute your 75In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 76requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 77in perl, and the threads created by this module will not be visible
59to perl. In the future, this module might make use of the native aio 78to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 79functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 80not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 81files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 82aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 83using threads anyway.
65 84
66Although the module will work with in the presence of other (Perl-) 85Although the module will work in the presence of other (Perl-) threads,
67threads, it is currently not reentrant in any way, so use appropriate 86it is currently not reentrant in any way, so use appropriate locking
68locking yourself, always call C<poll_cb> from within the same thread, or 87yourself, always call C<poll_cb> from within the same thread, or never
69never call C<poll_cb> (or other C<aio_> functions) recursively. 88call C<poll_cb> (or other C<aio_> functions) recursively.
89
90=head2 EXAMPLE
91
92This is a simple example that uses the Event module and loads
93F</etc/passwd> asynchronously:
94
95 use Fcntl;
96 use Event;
97 use IO::AIO;
98
99 # register the IO::AIO callback with Event
100 Event->io (fd => IO::AIO::poll_fileno,
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103
104 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub {
106 my $fh = shift
107 or die "error while opening: $!";
108
109 # stat'ing filehandles is generally non-blocking
110 my $size = -s $fh;
111
112 # queue a request to read the file
113 my $contents;
114 aio_read $fh, 0, $size, $contents, 0, sub {
115 $_[0] == $size
116 or die "short read: $!";
117
118 close $fh;
119
120 # file contents now in $contents
121 print $contents;
122
123 # exit event loop and program
124 Event::unloop;
125 };
126 };
127
128 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc.
130
131 # process events as long as there are some:
132 Event::loop;
70 133
71=head1 REQUEST ANATOMY AND LIFETIME 134=head1 REQUEST ANATOMY AND LIFETIME
72 135
73Every C<aio_*> function creates a request. which is a C data structure not 136Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 137directly visible to Perl.
… …
116Request has reached the end of its lifetime and holds no resources anymore 179Request has reached the end of its lifetime and holds no resources anymore
117(except possibly for the Perl object, but its connection to the actual 180(except possibly for the Perl object, but its connection to the actual
118aio request is severed and calling its methods will either do nothing or 181aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 182result in a runtime error).
120 183
184=back
185
121=cut 186=cut
122 187
123package IO::AIO; 188package IO::AIO;
189
190use Carp ();
124 191
125no warnings; 192no warnings;
126use strict 'vars'; 193use strict 'vars';
127 194
128use base 'Exporter'; 195use base 'Exporter';
129 196
130BEGIN { 197BEGIN {
131 our $VERSION = '2.0'; 198 our $VERSION = '3.07';
132 199
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 200 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 201 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136 aio_group aio_nop); 203 aio_fdatasync aio_pathsync aio_readahead
204 aio_rename aio_link aio_move aio_copy aio_group
205 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
206 aio_chmod aio_utime aio_truncate);
207
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 210 min_parallel max_parallel max_idle
211 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs);
140 213
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 214 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 215
143 require XSLoader; 216 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 217 XSLoader::load ("IO::AIO", $VERSION);
145} 218}
146 219
147=head1 FUNCTIONS 220=head1 FUNCTIONS
148 221
149=head2 AIO FUNCTIONS 222=head2 AIO REQUEST FUNCTIONS
150 223
151All the C<aio_*> calls are more or less thin wrappers around the syscall 224All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 225with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 226and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 227which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 230syscall has been executed asynchronously.
158 231
159All functions expecting a filehandle keep a copy of the filehandle 232All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 233internally until the request has finished.
161 234
162All requests return objects of type L<IO::AIO::REQ> that allow further 235All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 236further manipulation of those requests while they are in-flight.
164 237
165The pathnames you pass to these routines I<must> be absolute and 238The pathnames you pass to these routines I<must> be absolute and
166encoded in byte form. The reason for the former is that at the time the 239encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 240request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 241changed. Alternatively, you can make sure that you never change the
169current working directory. 242current working directory anywhere in the program and then use relative
243paths.
170 244
171To encode pathnames to byte form, either make sure you either: a) 245To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 246in filenames you got from outside (command line, readdir etc.) without
173etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode 247tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174your pathnames to the locale (or other) encoding in effect in the user 248your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 249environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 250use something else to ensure your scalar has the correct contents.
251
252This works, btw. independent of the internal UTF-8 bit, which IO::AIO
253handles correctly wether it is set or not.
177 254
178=over 4 255=over 4
179 256
180=item $prev_pri = aioreq_pri [$pri] 257=item $prev_pri = aioreq_pri [$pri]
181 258
… …
201 aio_read $_[0], ..., sub { 278 aio_read $_[0], ..., sub {
202 ... 279 ...
203 }; 280 };
204 }; 281 };
205 282
283
206=item aioreq_nice $pri_adjust 284=item aioreq_nice $pri_adjust
207 285
208Similar to C<aioreq_pri>, but subtracts the given value from the current 286Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 287priority, so the effect is cumulative.
288
210 289
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 290=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 291
213Asynchronously open or create a file and call the callback with a newly 292Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 293created filehandle for the file.
… …
220list. They are the same as used by C<sysopen>. 299list. They are the same as used by C<sysopen>.
221 300
222Likewise, C<$mode> specifies the mode of the newly created file, if it 301Likewise, C<$mode> specifies the mode of the newly created file, if it
223didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 302didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224except that it is mandatory (i.e. use C<0> if you don't create new files, 303except that it is mandatory (i.e. use C<0> if you don't create new files,
225and C<0666> or C<0777> if you do). 304and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
305by the umask in effect then the request is being executed, so better never
306change the umask.
226 307
227Example: 308Example:
228 309
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 310 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 311 if ($_[0]) {
… …
233 } else { 314 } else {
234 die "open failed: $!\n"; 315 die "open failed: $!\n";
235 } 316 }
236 }; 317 };
237 318
319
238=item aio_close $fh, $callback->($status) 320=item aio_close $fh, $callback->($status)
239 321
240Asynchronously close a file and call the callback with the result 322Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 323code.
242filehandle here, as perl will likely close the file descriptor another
243time when the filehandle is destroyed. Normally, you can safely call perls
244C<close> or just let filehandles go out of scope.
245 324
246This is supposed to be a bug in the API, so that might change. It's 325Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247therefore best to avoid this function. 326closing the file descriptor associated with the filehandle itself.
327
328Therefore, C<aio_close> will not close the filehandle - instead it will
329use dup2 to overwrite the file descriptor with the write-end of a pipe
330(the pipe fd will be created on demand and will be cached).
331
332Or in other words: the file descriptor will be closed, but it will not be
333free for reuse until the perl filehandle is closed.
334
335=cut
248 336
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 337=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 338
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 339=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 340
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 341Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254into the scalar given by C<data> and offset C<dataoffset> and calls the 342into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255callback without the actual number of bytes read (or -1 on error, just 343callback without the actual number of bytes read (or -1 on error, just
256like the syscall). 344like the syscall).
257 345
346If C<$offset> is undefined, then the current file descriptor offset will
347be used (and updated), otherwise the file descriptor offset will not be
348changed by these calls.
349
350If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
351
352If C<$dataoffset> is less than zero, it will be counted from the end of
353C<$data>.
354
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 355The C<$data> scalar I<MUST NOT> be modified in any way while the request
259is outstanding. Modifying it can result in segfaults or WW3 (if the 356is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 357the necessary/optional hardware is installed).
261 358
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 359Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 360offset C<0> within the scalar:
264 361
265 aio_read $fh, 7, 15, $buffer, 0, sub { 362 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 363 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 364 print "read $_[0] bytes: <$buffer>\n";
268 }; 365 };
269 366
270=item aio_move $srcpath, $dstpath, $callback->($status)
271
272Try to move the I<file> (directories not supported as either source or
273destination) from C<$srcpath> to C<$dstpath> and call the callback with
274the C<0> (error) or C<-1> ok.
275
276This is a composite request that tries to rename(2) the file first. If
277rename files with C<EXDEV>, it creates the destination file with mode 0200
278and copies the contents of the source file into it using C<aio_sendfile>,
279followed by restoring atime, mtime, access mode and uid/gid, in that
280order, and unlinking the C<$srcpath>.
281
282If an error occurs, the partial destination file will be unlinked, if
283possible, except when setting atime, mtime, access mode and uid/gid, where
284errors are being ignored.
285
286=cut
287
288sub aio_move($$$) {
289 my ($src, $dst, $cb) = @_;
290
291 my $pri = aioreq_pri;
292 my $grp = aio_group $cb;
293
294 aioreq_pri $pri;
295 add $grp aio_rename $src, $dst, sub {
296 if ($_[0] && $! == EXDEV) {
297 aioreq_pri $pri;
298 add $grp aio_open $src, O_RDONLY, 0, sub {
299 if (my $src_fh = $_[0]) {
300 my @stat = stat $src_fh;
301
302 aioreq_pri $pri;
303 add $grp aio_open $dst, O_WRONLY, 0200, sub {
304 if (my $dst_fh = $_[0]) {
305 aioreq_pri $pri;
306 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
307 close $src_fh;
308
309 if ($_[0] == $stat[7]) {
310 utime $stat[8], $stat[9], $dst;
311 chmod $stat[2] & 07777, $dst_fh;
312 chown $stat[4], $stat[5], $dst_fh;
313 close $dst_fh;
314
315 aioreq_pri $pri;
316 add $grp aio_unlink $src, sub {
317 $grp->result ($_[0]);
318 };
319 } else {
320 my $errno = $!;
321 aioreq_pri $pri;
322 add $grp aio_unlink $dst, sub {
323 $! = $errno;
324 $grp->result (-1);
325 };
326 }
327 };
328 } else {
329 $grp->result (-1);
330 }
331 },
332
333 } else {
334 $grp->result (-1);
335 }
336 };
337 } else {
338 $grp->result ($_[0]);
339 }
340 };
341
342 $grp
343}
344 367
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 368=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 369
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 370Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
348reading at byte offset C<$in_offset>, and starts writing at the current 371reading at byte offset C<$in_offset>, and starts writing at the current
… …
362C<$in_fh> than are written, and there is no way to find out how many 385C<$in_fh> than are written, and there is no way to find out how many
363bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 386bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
364provides the number of bytes written to C<$out_fh>. Only if the result 387provides the number of bytes written to C<$out_fh>. Only if the result
365value equals C<$length> one can assume that C<$length> bytes have been 388value equals C<$length> one can assume that C<$length> bytes have been
366read. 389read.
390
367 391
368=item aio_readahead $fh,$offset,$length, $callback->($retval) 392=item aio_readahead $fh,$offset,$length, $callback->($retval)
369 393
370C<aio_readahead> populates the page cache with data from a file so that 394C<aio_readahead> populates the page cache with data from a file so that
371subsequent reads from that file will not block on disk I/O. The C<$offset> 395subsequent reads from that file will not block on disk I/O. The C<$offset>
… …
377file. The current file offset of the file is left unchanged. 401file. The current file offset of the file is left unchanged.
378 402
379If that syscall doesn't exist (likely if your OS isn't Linux) it will be 403If that syscall doesn't exist (likely if your OS isn't Linux) it will be
380emulated by simply reading the data, which would have a similar effect. 404emulated by simply reading the data, which would have a similar effect.
381 405
406
382=item aio_stat $fh_or_path, $callback->($status) 407=item aio_stat $fh_or_path, $callback->($status)
383 408
384=item aio_lstat $fh, $callback->($status) 409=item aio_lstat $fh, $callback->($status)
385 410
386Works like perl's C<stat> or C<lstat> in void context. The callback will 411Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
399 aio_stat "/etc/passwd", sub { 424 aio_stat "/etc/passwd", sub {
400 $_[0] and die "stat failed: $!"; 425 $_[0] and die "stat failed: $!";
401 print "size is ", -s _, "\n"; 426 print "size is ", -s _, "\n";
402 }; 427 };
403 428
429
430=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
431
432Works like perl's C<utime> function (including the special case of $atime
433and $mtime being undef). Fractional times are supported if the underlying
434syscalls support them.
435
436When called with a pathname, uses utimes(2) if available, otherwise
437utime(2). If called on a file descriptor, uses futimes(2) if available,
438otherwise returns ENOSYS, so this is not portable.
439
440Examples:
441
442 # set atime and mtime to current time (basically touch(1)):
443 aio_utime "path", undef, undef;
444 # set atime to current time and mtime to beginning of the epoch:
445 aio_utime "path", time, undef; # undef==0
446
447
448=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
449
450Works like perl's C<chown> function, except that C<undef> for either $uid
451or $gid is being interpreted as "do not change" (but -1 can also be used).
452
453Examples:
454
455 # same as "chown root path" in the shell:
456 aio_chown "path", 0, -1;
457 # same as above:
458 aio_chown "path", 0, undef;
459
460
461=item aio_truncate $fh_or_path, $offset, $callback->($status)
462
463Works like truncate(2) or ftruncate(2).
464
465
466=item aio_chmod $fh_or_path, $mode, $callback->($status)
467
468Works like perl's C<chmod> function.
469
470
404=item aio_unlink $pathname, $callback->($status) 471=item aio_unlink $pathname, $callback->($status)
405 472
406Asynchronously unlink (delete) a file and call the callback with the 473Asynchronously unlink (delete) a file and call the callback with the
407result code. 474result code.
408 475
476
477=item aio_mknod $path, $mode, $dev, $callback->($status)
478
479[EXPERIMENTAL]
480
481Asynchronously create a device node (or fifo). See mknod(2).
482
483The only (POSIX-) portable way of calling this function is:
484
485 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
486
487
409=item aio_link $srcpath, $dstpath, $callback->($status) 488=item aio_link $srcpath, $dstpath, $callback->($status)
410 489
411Asynchronously create a new link to the existing object at C<$srcpath> at 490Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 491the path C<$dstpath> and call the callback with the result code.
413 492
493
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 494=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 495
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 496Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
417the path C<$dstpath> and call the callback with the result code. 497the path C<$dstpath> and call the callback with the result code.
418 498
499
500=item aio_readlink $path, $callback->($link)
501
502Asynchronously read the symlink specified by C<$path> and pass it to
503the callback. If an error occurs, nothing or undef gets passed to the
504callback.
505
506
419=item aio_rename $srcpath, $dstpath, $callback->($status) 507=item aio_rename $srcpath, $dstpath, $callback->($status)
420 508
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 509Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 510rename(2) and call the callback with the result code.
423 511
512
513=item aio_mkdir $pathname, $mode, $callback->($status)
514
515Asynchronously mkdir (create) a directory and call the callback with
516the result code. C<$mode> will be modified by the umask at the time the
517request is executed, so do not change your umask.
518
519
424=item aio_rmdir $pathname, $callback->($status) 520=item aio_rmdir $pathname, $callback->($status)
425 521
426Asynchronously rmdir (delete) a directory and call the callback with the 522Asynchronously rmdir (delete) a directory and call the callback with the
427result code. 523result code.
524
428 525
429=item aio_readdir $pathname, $callback->($entries) 526=item aio_readdir $pathname, $callback->($entries)
430 527
431Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 528Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432directory (i.e. opendir + readdir + closedir). The entries will not be 529directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 530sorted, and will B<NOT> include the C<.> and C<..> entries.
434 531
435The callback a single argument which is either C<undef> or an array-ref 532The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 533with the filenames.
534
535
536=item aio_load $path, $data, $callback->($status)
537
538This is a composite request that tries to fully load the given file into
539memory. Status is the same as with aio_read.
540
541=cut
542
543sub aio_load($$;$) {
544 my ($path, undef, $cb) = @_;
545 my $data = \$_[1];
546
547 my $pri = aioreq_pri;
548 my $grp = aio_group $cb;
549
550 aioreq_pri $pri;
551 add $grp aio_open $path, O_RDONLY, 0, sub {
552 my $fh = shift
553 or return $grp->result (-1);
554
555 aioreq_pri $pri;
556 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
557 $grp->result ($_[0]);
558 };
559 };
560
561 $grp
562}
563
564=item aio_copy $srcpath, $dstpath, $callback->($status)
565
566Try to copy the I<file> (directories not supported as either source or
567destination) from C<$srcpath> to C<$dstpath> and call the callback with
568the C<0> (error) or C<-1> ok.
569
570This is a composite request that creates the destination file with
571mode 0200 and copies the contents of the source file into it using
572C<aio_sendfile>, followed by restoring atime, mtime, access mode and
573uid/gid, in that order.
574
575If an error occurs, the partial destination file will be unlinked, if
576possible, except when setting atime, mtime, access mode and uid/gid, where
577errors are being ignored.
578
579=cut
580
581sub aio_copy($$;$) {
582 my ($src, $dst, $cb) = @_;
583
584 my $pri = aioreq_pri;
585 my $grp = aio_group $cb;
586
587 aioreq_pri $pri;
588 add $grp aio_open $src, O_RDONLY, 0, sub {
589 if (my $src_fh = $_[0]) {
590 my @stat = stat $src_fh;
591
592 aioreq_pri $pri;
593 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
594 if (my $dst_fh = $_[0]) {
595 aioreq_pri $pri;
596 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
597 if ($_[0] == $stat[7]) {
598 $grp->result (0);
599 close $src_fh;
600
601 # those should not normally block. should. should.
602 utime $stat[8], $stat[9], $dst;
603 chmod $stat[2] & 07777, $dst_fh;
604 chown $stat[4], $stat[5], $dst_fh;
605
606 aioreq_pri $pri;
607 add $grp aio_close $dst_fh;
608 } else {
609 $grp->result (-1);
610 close $src_fh;
611 close $dst_fh;
612
613 aioreq $pri;
614 add $grp aio_unlink $dst;
615 }
616 };
617 } else {
618 $grp->result (-1);
619 }
620 },
621
622 } else {
623 $grp->result (-1);
624 }
625 };
626
627 $grp
628}
629
630=item aio_move $srcpath, $dstpath, $callback->($status)
631
632Try to move the I<file> (directories not supported as either source or
633destination) from C<$srcpath> to C<$dstpath> and call the callback with
634the C<0> (error) or C<-1> ok.
635
636This is a composite request that tries to rename(2) the file first. If
637rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
638that is successful, unlinking the C<$srcpath>.
639
640=cut
641
642sub aio_move($$;$) {
643 my ($src, $dst, $cb) = @_;
644
645 my $pri = aioreq_pri;
646 my $grp = aio_group $cb;
647
648 aioreq_pri $pri;
649 add $grp aio_rename $src, $dst, sub {
650 if ($_[0] && $! == EXDEV) {
651 aioreq_pri $pri;
652 add $grp aio_copy $src, $dst, sub {
653 $grp->result ($_[0]);
654
655 if (!$_[0]) {
656 aioreq_pri $pri;
657 add $grp aio_unlink $src;
658 }
659 };
660 } else {
661 $grp->result ($_[0]);
662 }
663 };
664
665 $grp
666}
437 667
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 668=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 669
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 670Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 671efficiently separate the entries of directory C<$path> into two sets of
… …
487as those tend to return 0 or 1 as link counts, which disables the 717as those tend to return 0 or 1 as link counts, which disables the
488directory counting heuristic. 718directory counting heuristic.
489 719
490=cut 720=cut
491 721
492sub aio_scandir($$$) { 722sub aio_scandir($$;$) {
493 my ($path, $maxreq, $cb) = @_; 723 my ($path, $maxreq, $cb) = @_;
494 724
495 my $pri = aioreq_pri; 725 my $pri = aioreq_pri;
496 726
497 my $grp = aio_group $cb; 727 my $grp = aio_group $cb;
… …
573 }; 803 };
574 804
575 $grp 805 $grp
576} 806}
577 807
808=item aio_rmtree $path, $callback->($status)
809
810Delete a directory tree starting (and including) C<$path>, return the
811status of the final C<rmdir> only. This is a composite request that
812uses C<aio_scandir> to recurse into and rmdir directories, and unlink
813everything else.
814
815=cut
816
817sub aio_rmtree;
818sub aio_rmtree($;$) {
819 my ($path, $cb) = @_;
820
821 my $pri = aioreq_pri;
822 my $grp = aio_group $cb;
823
824 aioreq_pri $pri;
825 add $grp aio_scandir $path, 0, sub {
826 my ($dirs, $nondirs) = @_;
827
828 my $dirgrp = aio_group sub {
829 add $grp aio_rmdir $path, sub {
830 $grp->result ($_[0]);
831 };
832 };
833
834 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
835 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
836
837 add $grp $dirgrp;
838 };
839
840 $grp
841}
842
843=item aio_sync $callback->($status)
844
845Asynchronously call sync and call the callback when finished.
846
578=item aio_fsync $fh, $callback->($status) 847=item aio_fsync $fh, $callback->($status)
579 848
580Asynchronously call fsync on the given filehandle and call the callback 849Asynchronously call fsync on the given filehandle and call the callback
581with the fsync result code. 850with the fsync result code.
582 851
… …
585Asynchronously call fdatasync on the given filehandle and call the 854Asynchronously call fdatasync on the given filehandle and call the
586callback with the fdatasync result code. 855callback with the fdatasync result code.
587 856
588If this call isn't available because your OS lacks it or it couldn't be 857If this call isn't available because your OS lacks it or it couldn't be
589detected, it will be emulated by calling C<fsync> instead. 858detected, it will be emulated by calling C<fsync> instead.
859
860=item aio_pathsync $path, $callback->($status)
861
862This request tries to open, fsync and close the given path. This is a
863composite request intended to sync directories after directory operations
864(E.g. rename). This might not work on all operating systems or have any
865specific effect, but usually it makes sure that directory changes get
866written to disc. It works for anything that can be opened for read-only,
867not just directories.
868
869Passes C<0> when everything went ok, and C<-1> on error.
870
871=cut
872
873sub aio_pathsync($;$) {
874 my ($path, $cb) = @_;
875
876 my $pri = aioreq_pri;
877 my $grp = aio_group $cb;
878
879 aioreq_pri $pri;
880 add $grp aio_open $path, O_RDONLY, 0, sub {
881 my ($fh) = @_;
882 if ($fh) {
883 aioreq_pri $pri;
884 add $grp aio_fsync $fh, sub {
885 $grp->result ($_[0]);
886
887 aioreq_pri $pri;
888 add $grp aio_close $fh;
889 };
890 } else {
891 $grp->result (-1);
892 }
893 };
894
895 $grp
896}
590 897
591=item aio_group $callback->(...) 898=item aio_group $callback->(...)
592 899
593This is a very special aio request: Instead of doing something, it is a 900This is a very special aio request: Instead of doing something, it is a
594container for other aio requests, which is useful if you want to bundle 901container for other aio requests, which is useful if you want to bundle
… …
706Their lifetime, simplified, looks like this: when they are empty, they 1013Their lifetime, simplified, looks like this: when they are empty, they
707will finish very quickly. If they contain only requests that are in the 1014will finish very quickly. If they contain only requests that are in the
708C<done> state, they will also finish. Otherwise they will continue to 1015C<done> state, they will also finish. Otherwise they will continue to
709exist. 1016exist.
710 1017
711That means after creating a group you have some time to add requests. And 1018That means after creating a group you have some time to add requests
712in the callbacks of those requests, you can add further requests to the 1019(precisely before the callback has been invoked, which is only done within
713group. And only when all those requests have finished will the the group 1020the C<poll_cb>). And in the callbacks of those requests, you can add
714itself finish. 1021further requests to the group. And only when all those requests have
1022finished will the the group itself finish.
715 1023
716=over 4 1024=over 4
717 1025
718=item add $grp ... 1026=item add $grp ...
719 1027
… …
731itself. Useful when you queued a lot of events but got a result early. 1039itself. Useful when you queued a lot of events but got a result early.
732 1040
733=item $grp->result (...) 1041=item $grp->result (...)
734 1042
735Set the result value(s) that will be passed to the group callback when all 1043Set the result value(s) that will be passed to the group callback when all
736subrequests have finished and set thre groups errno to the current value 1044subrequests have finished and set the groups errno to the current value
737of errno (just like calling C<errno> without an error number). By default, 1045of errno (just like calling C<errno> without an error number). By default,
738no argument will be passed and errno is zero. 1046no argument will be passed and errno is zero.
739 1047
740=item $grp->errno ([$errno]) 1048=item $grp->errno ([$errno])
741 1049
… …
794 1102
795=back 1103=back
796 1104
797=head2 SUPPORT FUNCTIONS 1105=head2 SUPPORT FUNCTIONS
798 1106
1107=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1108
799=over 4 1109=over 4
800 1110
801=item $fileno = IO::AIO::poll_fileno 1111=item $fileno = IO::AIO::poll_fileno
802 1112
803Return the I<request result pipe file descriptor>. This filehandle must be 1113Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 1117
808See C<poll_cb> for an example. 1118See C<poll_cb> for an example.
809 1119
810=item IO::AIO::poll_cb 1120=item IO::AIO::poll_cb
811 1121
812Process all outstanding events on the result pipe. You have to call this 1122Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1123regularly. Returns C<0> if all events could be processed, or C<-1> if it
814when no events are outstanding. 1124returned earlier for whatever reason. Returns immediately when no events
1125are outstanding. The amount of events processed depends on the settings of
1126C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1127
816If not all requests were processed for whatever reason, the filehandle 1128If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1129will still be ready when C<poll_cb> returns, so normally you don't have to
1130do anything special to have it called later.
818 1131
819Example: Install an Event watcher that automatically calls 1132Example: Install an Event watcher that automatically calls
820IO::AIO::poll_cb with high priority: 1133IO::AIO::poll_cb with high priority:
821 1134
822 Event->io (fd => IO::AIO::poll_fileno, 1135 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1136 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1137 cb => \&IO::AIO::poll_cb);
825 1138
826=item IO::AIO::poll_some $max_requests 1139=item IO::AIO::max_poll_reqs $nreqs
827 1140
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1141=item IO::AIO::max_poll_time $seconds
829at a time.
830 1142
831Useful if you want to ensure some level of interactiveness when perl is 1143These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1144that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1145the maximum amount of time (default C<0>, meaning infinity) spent in
1146C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1147of time C<poll_cb> is allowed to use).
1148
1149Setting C<max_poll_time> to a non-zero value creates an overhead of one
1150syscall per request processed, which is not normally a problem unless your
1151callbacks are really really fast or your OS is really really slow (I am
1152not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1153
1154Setting these is useful if you want to ensure some level of
1155interactiveness when perl is not fast enough to process all requests in
1156time.
1157
1158For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1159
834Example: Install an Event watcher that automatically calls 1160Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1161IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1162program get the CPU sometimes even under high AIO load.
837 1163
1164 # try not to spend much more than 0.1s in poll_cb
1165 IO::AIO::max_poll_time 0.1;
1166
1167 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1168 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1169 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1170 cb => &IO::AIO::poll_cb);
841 1171
842=item IO::AIO::poll_wait 1172=item IO::AIO::poll_wait
843 1173
1174If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1175phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1176does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1177synchronously wait for some requests to finish).
847 1178
848See C<nreqs> for an example. 1179See C<nreqs> for an example.
849 1180
1181=item IO::AIO::poll
1182
1183Waits until some requests have been handled.
1184
1185Returns the number of requests processed, but is otherwise strictly
1186equivalent to:
1187
1188 IO::AIO::poll_wait, IO::AIO::poll_cb
1189
850=item IO::AIO::nreqs 1190=item IO::AIO::flush
851 1191
852Returns the number of requests currently in the ready, execute or pending 1192Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1193
855Example: wait till there are no outstanding requests anymore: 1194Strictly equivalent to:
856 1195
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1196 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1197 while IO::AIO::nreqs;
859 1198
860=item IO::AIO::nready 1199=back
861 1200
862Returns the number of requests currently in the ready state (not yet 1201=head3 CONTROLLING THE NUMBER OF THREADS
863executed).
864 1202
865=item IO::AIO::npending 1203=over
866
867Returns the number of requests currently in the pending state (executed,
868but not yet processed by poll_cb).
869
870=item IO::AIO::flush
871
872Wait till all outstanding AIO requests have been handled.
873
874Strictly equivalent to:
875
876 IO::AIO::poll_wait, IO::AIO::poll_cb
877 while IO::AIO::nreqs;
878
879=item IO::AIO::poll
880
881Waits until some requests have been handled.
882
883Strictly equivalent to:
884
885 IO::AIO::poll_wait, IO::AIO::poll_cb
886 if IO::AIO::nreqs;
887 1204
888=item IO::AIO::min_parallel $nthreads 1205=item IO::AIO::min_parallel $nthreads
889 1206
890Set the minimum number of AIO threads to C<$nthreads>. The current 1207Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1208default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1209concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1210however, is unlimited).
894 1211
895IO::AIO starts threads only on demand, when an AIO request is queued and 1212IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1213no free thread exists. Please note that queueing up a hundred requests can
1214create demand for a hundred threads, even if it turns out that everything
1215is in the cache and could have been processed faster by a single thread.
897 1216
898It is recommended to keep the number of threads relatively low, as some 1217It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1218Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1219(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1220versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1234This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1235that all threads are killed and that there are no outstanding requests.
917 1236
918Under normal circumstances you don't need to call this function. 1237Under normal circumstances you don't need to call this function.
919 1238
1239=item IO::AIO::max_idle $nthreads
1240
1241Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1242threads that did not get a request to process within 10 seconds). That
1243means if a thread becomes idle while C<$nthreads> other threads are also
1244idle, it will free its resources and exit.
1245
1246This is useful when you allow a large number of threads (e.g. 100 or 1000)
1247to allow for extremely high load situations, but want to free resources
1248under normal circumstances (1000 threads can easily consume 30MB of RAM).
1249
1250The default is probably ok in most situations, especially if thread
1251creation is fast. If thread creation is very slow on your system you might
1252want to use larger values.
1253
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1254=item IO::AIO::max_outstanding $maxreqs
921 1255
922This is a very bad function to use in interactive programs because it 1256This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1257blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1258use an C<aio_group> together with a feed callback.
925 1259
926Sets the maximum number of outstanding requests to C<$nreqs>. If you 1260Sets the maximum number of outstanding requests to C<$nreqs>. If you
927to queue up more than this number of requests, the next call to the 1261do queue up more than this number of requests, the next call to the
928C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) 1262C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
929function will block until the limit is no longer exceeded. 1263function will block until the limit is no longer exceeded.
930 1264
931The default value is very large, so there is no practical limit on the 1265The default value is very large, so there is no practical limit on the
932number of outstanding requests. 1266number of outstanding requests.
933 1267
934You can still queue as many requests as you want. Therefore, 1268You can still queue as many requests as you want. Therefore,
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1269C<max_outstanding> is mainly useful in simple scripts (with low values) or
936as a stop gap to shield against fatal memory overflow (with large values). 1270as a stop gap to shield against fatal memory overflow (with large values).
937 1271
938=back 1272=back
939 1273
1274=head3 STATISTICAL INFORMATION
1275
1276=over
1277
1278=item IO::AIO::nreqs
1279
1280Returns the number of requests currently in the ready, execute or pending
1281states (i.e. for which their callback has not been invoked yet).
1282
1283Example: wait till there are no outstanding requests anymore:
1284
1285 IO::AIO::poll_wait, IO::AIO::poll_cb
1286 while IO::AIO::nreqs;
1287
1288=item IO::AIO::nready
1289
1290Returns the number of requests currently in the ready state (not yet
1291executed).
1292
1293=item IO::AIO::npending
1294
1295Returns the number of requests currently in the pending state (executed,
1296but not yet processed by poll_cb).
1297
1298=back
1299
940=cut 1300=cut
941 1301
942# support function to convert a fd into a perl filehandle
943sub _fd2fh {
944 return undef if $_[0] < 0;
945
946 # try to generate nice filehandles
947 my $sym = "IO::AIO::fd#$_[0]";
948 local *$sym;
949
950 open *$sym, "+<&=$_[0]" # usually works under any unix
951 or open *$sym, "<&=$_[0]" # cygwin needs this
952 or open *$sym, ">&=$_[0]" # or this
953 or return undef;
954
955 *$sym
956}
957
958min_parallel 8; 1302min_parallel 8;
1303
1304END { flush }
959 1305
9601; 13061;
961 1307
962=head2 FORK BEHAVIOUR 1308=head2 FORK BEHAVIOUR
963 1309
… …
983bytes of memory. In addition, stat requests need a stat buffer (possibly 1329bytes of memory. In addition, stat requests need a stat buffer (possibly
984a few hundred bytes), readdir requires a result buffer and so on. Perl 1330a few hundred bytes), readdir requires a result buffer and so on. Perl
985scalars and other data passed into aio requests will also be locked and 1331scalars and other data passed into aio requests will also be locked and
986will consume memory till the request has entered the done state. 1332will consume memory till the request has entered the done state.
987 1333
988This is now awfully much, so queuing lots of requests is not usually a 1334This is not awfully much, so queuing lots of requests is not usually a
989problem. 1335problem.
990 1336
991Per-thread usage: 1337Per-thread usage:
992 1338
993In the execution phase, some aio requests require more memory for 1339In the execution phase, some aio requests require more memory for
… …
998 1344
999Known bugs will be fixed in the next release. 1345Known bugs will be fixed in the next release.
1000 1346
1001=head1 SEE ALSO 1347=head1 SEE ALSO
1002 1348
1003L<Coro::AIO>. 1349L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1350more natural syntax.
1004 1351
1005=head1 AUTHOR 1352=head1 AUTHOR
1006 1353
1007 Marc Lehmann <schmorp@schmorp.de> 1354 Marc Lehmann <schmorp@schmorp.de>
1008 http://home.schmorp.de/ 1355 http://home.schmorp.de/

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