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Revision 1.108 by root, Fri Jun 1 13:25:50 2007 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
… …
50 51
51=head1 DESCRIPTION 52=head1 DESCRIPTION
52 53
53This module implements asynchronous I/O using whatever means your 54This module implements asynchronous I/O using whatever means your
54operating system supports. 55operating system supports.
56
57Asynchronous means that operations that can normally block your program
58(e.g. reading from disk) will be done asynchronously: the operation
59will still block, but you can do something else in the meantime. This
60is extremely useful for programs that need to stay interactive even
61when doing heavy I/O (GUI programs, high performance network servers
62etc.), but can also be used to easily do operations in parallel that are
63normally done sequentially, e.g. stat'ing many files, which is much faster
64on a RAID volume or over NFS when you do a number of stat operations
65concurrently.
66
67While most of this works on all types of file descriptors (for
68example sockets), using these functions on file descriptors that
69support nonblocking operation (again, sockets, pipes etc.) is very
70inefficient. Use an event loop for that (such as the L<Event|Event>
71module): IO::AIO will naturally fit into such an event loop itself.
55 72
56In this version, a number of threads are started that execute your 73In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 74requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 75in 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 76to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 77functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 78not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 79files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 80aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 81using threads anyway.
65 82
66Although the module will work with in the presence of other (Perl-) 83Although the module will work in the presence of other (Perl-) threads,
67threads, it is currently not reentrant in any way, so use appropriate 84it is currently not reentrant in any way, so use appropriate locking
68locking yourself, always call C<poll_cb> from within the same thread, or 85yourself, always call C<poll_cb> from within the same thread, or never
69never call C<poll_cb> (or other C<aio_> functions) recursively. 86call C<poll_cb> (or other C<aio_> functions) recursively.
87
88=head2 EXAMPLE
89
90This is a simple example that uses the Event module and loads
91F</etc/passwd> asynchronously:
92
93 use Fcntl;
94 use Event;
95 use IO::AIO;
96
97 # register the IO::AIO callback with Event
98 Event->io (fd => IO::AIO::poll_fileno,
99 poll => 'r',
100 cb => \&IO::AIO::poll_cb);
101
102 # queue the request to open /etc/passwd
103 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 my $fh = shift
105 or die "error while opening: $!";
106
107 # stat'ing filehandles is generally non-blocking
108 my $size = -s $fh;
109
110 # queue a request to read the file
111 my $contents;
112 aio_read $fh, 0, $size, $contents, 0, sub {
113 $_[0] == $size
114 or die "short read: $!";
115
116 close $fh;
117
118 # file contents now in $contents
119 print $contents;
120
121 # exit event loop and program
122 Event::unloop;
123 };
124 };
125
126 # possibly queue up other requests, or open GUI windows,
127 # check for sockets etc. etc.
128
129 # process events as long as there are some:
130 Event::loop;
70 131
71=head1 REQUEST ANATOMY AND LIFETIME 132=head1 REQUEST ANATOMY AND LIFETIME
72 133
73Every C<aio_*> function creates a request. which is a C data structure not 134Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 135directly visible to Perl.
… …
116Request has reached the end of its lifetime and holds no resources anymore 177Request 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 178(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 179aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 180result in a runtime error).
120 181
182=back
183
121=cut 184=cut
122 185
123package IO::AIO; 186package IO::AIO;
124 187
125no warnings; 188no warnings;
126use strict 'vars'; 189use strict 'vars';
127 190
128use base 'Exporter'; 191use base 'Exporter';
129 192
130BEGIN { 193BEGIN {
131 our $VERSION = '2.0'; 194 our $VERSION = '2.4';
132 195
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 196 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
134 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 197 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 198 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
136 aio_group aio_nop); 199 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
200 aio_chown aio_chmod aio_utime);
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 203 min_parallel max_parallel max_idle
204 nreqs nready npending nthreads
205 max_poll_time max_poll_reqs);
140 206
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 207 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 208
143 require XSLoader; 209 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 210 XSLoader::load ("IO::AIO", $VERSION);
145} 211}
146 212
147=head1 FUNCTIONS 213=head1 FUNCTIONS
148 214
149=head2 AIO FUNCTIONS 215=head2 AIO REQUEST FUNCTIONS
150 216
151All the C<aio_*> calls are more or less thin wrappers around the syscall 217All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 218with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 219and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 220which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 223syscall has been executed asynchronously.
158 224
159All functions expecting a filehandle keep a copy of the filehandle 225All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 226internally until the request has finished.
161 227
162All requests return objects of type L<IO::AIO::REQ> that allow further 228All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 229further manipulation of those requests while they are in-flight.
164 230
165The pathnames you pass to these routines I<must> be absolute and 231The 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 232encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 233request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 234changed. Alternatively, you can make sure that you never change the
169current working directory. 235current working directory anywhere in the program and then use relative
236paths.
170 237
171To encode pathnames to byte form, either make sure you either: a) 238To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 239in 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 240tinkering, 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 241your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 242environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 243use something else to ensure your scalar has the correct contents.
244
245This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246handles correctly wether it is set or not.
177 247
178=over 4 248=over 4
179 249
180=item $prev_pri = aioreq_pri [$pri] 250=item $prev_pri = aioreq_pri [$pri]
181 251
… …
201 aio_read $_[0], ..., sub { 271 aio_read $_[0], ..., sub {
202 ... 272 ...
203 }; 273 };
204 }; 274 };
205 275
276
206=item aioreq_nice $pri_adjust 277=item aioreq_nice $pri_adjust
207 278
208Similar to C<aioreq_pri>, but subtracts the given value from the current 279Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 280priority, so the effect is cumulative.
281
210 282
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 283=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 284
213Asynchronously open or create a file and call the callback with a newly 285Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 286created filehandle for the file.
… …
220list. They are the same as used by C<sysopen>. 292list. They are the same as used by C<sysopen>.
221 293
222Likewise, C<$mode> specifies the mode of the newly created file, if it 294Likewise, C<$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>, 295didn'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, 296except 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). 297and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
298by the umask in effect then the request is being executed, so better never
299change the umask.
226 300
227Example: 301Example:
228 302
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 303 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 304 if ($_[0]) {
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233 } else { 307 } else {
234 die "open failed: $!\n"; 308 die "open failed: $!\n";
235 } 309 }
236 }; 310 };
237 311
312
238=item aio_close $fh, $callback->($status) 313=item aio_close $fh, $callback->($status)
239 314
240Asynchronously close a file and call the callback with the result 315Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 316code. I<WARNING:> although accepted, you should not pass in a perl
242filehandle here, as perl will likely close the file descriptor another 317filehandle here, as perl will likely close the file descriptor another
… …
244C<close> or just let filehandles go out of scope. 319C<close> or just let filehandles go out of scope.
245 320
246This is supposed to be a bug in the API, so that might change. It's 321This is supposed to be a bug in the API, so that might change. It's
247therefore best to avoid this function. 322therefore best to avoid this function.
248 323
324
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 325=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 326
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 327=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 328
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 329Reads 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 330into 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 331callback without the actual number of bytes read (or -1 on error, just
256like the syscall). 332like the syscall). If C<offset> is undefined, then the current file offset
333will be used (and updated), otherwise the file offset will not be changed
334by these calls.
257 335
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 336The C<$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 337is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 338the necessary/optional hardware is installed).
261 339
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 340Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 341offset C<0> within the scalar:
264 342
265 aio_read $fh, 7, 15, $buffer, 0, sub { 343 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 344 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 345 print "read $_[0] bytes: <$buffer>\n";
268 }; 346 };
269 347
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}
344 348
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 349=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 350
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 351Tries 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 352reading 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 366C<$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 367bytes 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 368provides 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 369value equals C<$length> one can assume that C<$length> bytes have been
366read. 370read.
371
367 372
368=item aio_readahead $fh,$offset,$length, $callback->($retval) 373=item aio_readahead $fh,$offset,$length, $callback->($retval)
369 374
370C<aio_readahead> populates the page cache with data from a file so that 375C<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> 376subsequent 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. 382file. The current file offset of the file is left unchanged.
378 383
379If that syscall doesn't exist (likely if your OS isn't Linux) it will be 384If 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. 385emulated by simply reading the data, which would have a similar effect.
381 386
387
382=item aio_stat $fh_or_path, $callback->($status) 388=item aio_stat $fh_or_path, $callback->($status)
383 389
384=item aio_lstat $fh, $callback->($status) 390=item aio_lstat $fh, $callback->($status)
385 391
386Works like perl's C<stat> or C<lstat> in void context. The callback will 392Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
399 aio_stat "/etc/passwd", sub { 405 aio_stat "/etc/passwd", sub {
400 $_[0] and die "stat failed: $!"; 406 $_[0] and die "stat failed: $!";
401 print "size is ", -s _, "\n"; 407 print "size is ", -s _, "\n";
402 }; 408 };
403 409
410
411=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
412
413Works like perl's C<utime> function (including the special case of $atime
414and $mtime being undef). Fractional times are supported if the underlying
415syscalls support them.
416
417When called with a pathname, uses utimes(2) if available, otherwise
418utime(2). If called on a file descriptor, uses futimes(2) if available,
419otherwise returns ENOSYS, so this is not portable.
420
421Examples:
422
423 # set atime and mtime to current time (basically touch(1)):
424 aio_utime "path", undef, undef;
425 # set atime to current time and mtime to beginning of the epoch:
426 aio_utime "path", time, undef; # undef==0
427
428
429=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
430
431Works like perl's C<chown> function, except that C<undef> for either $uid
432or $gid is being interpreted as "do not change" (but -1 can also be used).
433
434Examples:
435
436 # same as "chown root path" in the shell:
437 aio_chown "path", 0, -1;
438 # same as above:
439 aio_chown "path", 0, undef;
440
441
442=item aio_chmod $fh_or_path, $mode, $callback->($status)
443
444Works like perl's C<chmod> function.
445
446
404=item aio_unlink $pathname, $callback->($status) 447=item aio_unlink $pathname, $callback->($status)
405 448
406Asynchronously unlink (delete) a file and call the callback with the 449Asynchronously unlink (delete) a file and call the callback with the
407result code. 450result code.
408 451
452
453=item aio_mknod $path, $mode, $dev, $callback->($status)
454
455[EXPERIMENTAL]
456
457Asynchronously create a device node (or fifo). See mknod(2).
458
459The only (POSIX-) portable way of calling this function is:
460
461 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
462
463
409=item aio_link $srcpath, $dstpath, $callback->($status) 464=item aio_link $srcpath, $dstpath, $callback->($status)
410 465
411Asynchronously create a new link to the existing object at C<$srcpath> at 466Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 467the path C<$dstpath> and call the callback with the result code.
413 468
469
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 470=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 471
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 472Asynchronously 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. 473the path C<$dstpath> and call the callback with the result code.
418 474
475
476=item aio_readlink $path, $callback->($link)
477
478Asynchronously read the symlink specified by C<$path> and pass it to
479the callback. If an error occurs, nothing or undef gets passed to the
480callback.
481
482
419=item aio_rename $srcpath, $dstpath, $callback->($status) 483=item aio_rename $srcpath, $dstpath, $callback->($status)
420 484
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 485Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 486rename(2) and call the callback with the result code.
423 487
488
489=item aio_mkdir $pathname, $mode, $callback->($status)
490
491Asynchronously mkdir (create) a directory and call the callback with
492the result code. C<$mode> will be modified by the umask at the time the
493request is executed, so do not change your umask.
494
495
424=item aio_rmdir $pathname, $callback->($status) 496=item aio_rmdir $pathname, $callback->($status)
425 497
426Asynchronously rmdir (delete) a directory and call the callback with the 498Asynchronously rmdir (delete) a directory and call the callback with the
427result code. 499result code.
500
428 501
429=item aio_readdir $pathname, $callback->($entries) 502=item aio_readdir $pathname, $callback->($entries)
430 503
431Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 504Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432directory (i.e. opendir + readdir + closedir). The entries will not be 505directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 506sorted, and will B<NOT> include the C<.> and C<..> entries.
434 507
435The callback a single argument which is either C<undef> or an array-ref 508The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 509with the filenames.
510
511
512=item aio_load $path, $data, $callback->($status)
513
514This is a composite request that tries to fully load the given file into
515memory. Status is the same as with aio_read.
516
517=cut
518
519sub aio_load($$;$) {
520 aio_block {
521 my ($path, undef, $cb) = @_;
522 my $data = \$_[1];
523
524 my $pri = aioreq_pri;
525 my $grp = aio_group $cb;
526
527 aioreq_pri $pri;
528 add $grp aio_open $path, O_RDONLY, 0, sub {
529 my $fh = shift
530 or return $grp->result (-1);
531
532 aioreq_pri $pri;
533 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
534 $grp->result ($_[0]);
535 };
536 };
537
538 $grp
539 }
540}
541
542=item aio_copy $srcpath, $dstpath, $callback->($status)
543
544Try to copy the I<file> (directories not supported as either source or
545destination) from C<$srcpath> to C<$dstpath> and call the callback with
546the C<0> (error) or C<-1> ok.
547
548This is a composite request that it creates the destination file with
549mode 0200 and copies the contents of the source file into it using
550C<aio_sendfile>, followed by restoring atime, mtime, access mode and
551uid/gid, in that order.
552
553If an error occurs, the partial destination file will be unlinked, if
554possible, except when setting atime, mtime, access mode and uid/gid, where
555errors are being ignored.
556
557=cut
558
559sub aio_copy($$;$) {
560 aio_block {
561 my ($src, $dst, $cb) = @_;
562
563 my $pri = aioreq_pri;
564 my $grp = aio_group $cb;
565
566 aioreq_pri $pri;
567 add $grp aio_open $src, O_RDONLY, 0, sub {
568 if (my $src_fh = $_[0]) {
569 my @stat = stat $src_fh;
570
571 aioreq_pri $pri;
572 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
573 if (my $dst_fh = $_[0]) {
574 aioreq_pri $pri;
575 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
576 if ($_[0] == $stat[7]) {
577 $grp->result (0);
578 close $src_fh;
579
580 # those should not normally block. should. should.
581 utime $stat[8], $stat[9], $dst;
582 chmod $stat[2] & 07777, $dst_fh;
583 chown $stat[4], $stat[5], $dst_fh;
584 close $dst_fh;
585 } else {
586 $grp->result (-1);
587 close $src_fh;
588 close $dst_fh;
589
590 aioreq $pri;
591 add $grp aio_unlink $dst;
592 }
593 };
594 } else {
595 $grp->result (-1);
596 }
597 },
598
599 } else {
600 $grp->result (-1);
601 }
602 };
603
604 $grp
605 }
606}
607
608=item aio_move $srcpath, $dstpath, $callback->($status)
609
610Try to move the I<file> (directories not supported as either source or
611destination) from C<$srcpath> to C<$dstpath> and call the callback with
612the C<0> (error) or C<-1> ok.
613
614This is a composite request that tries to rename(2) the file first. If
615rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
616that is successful, unlinking the C<$srcpath>.
617
618=cut
619
620sub aio_move($$;$) {
621 aio_block {
622 my ($src, $dst, $cb) = @_;
623
624 my $pri = aioreq_pri;
625 my $grp = aio_group $cb;
626
627 aioreq_pri $pri;
628 add $grp aio_rename $src, $dst, sub {
629 if ($_[0] && $! == EXDEV) {
630 aioreq_pri $pri;
631 add $grp aio_copy $src, $dst, sub {
632 $grp->result ($_[0]);
633
634 if (!$_[0]) {
635 aioreq_pri $pri;
636 add $grp aio_unlink $src;
637 }
638 };
639 } else {
640 $grp->result ($_[0]);
641 }
642 };
643
644 $grp
645 }
646}
437 647
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 648=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 649
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 650Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 651efficiently separate the entries of directory C<$path> into two sets of
… …
443recurse into (everything else, including symlinks to directories). 653recurse into (everything else, including symlinks to directories).
444 654
445C<aio_scandir> is a composite request that creates of many sub requests_ 655C<aio_scandir> is a composite request that creates of many sub requests_
446C<$maxreq> specifies the maximum number of outstanding aio requests that 656C<$maxreq> specifies the maximum number of outstanding aio requests that
447this function generates. If it is C<< <= 0 >>, then a suitable default 657this function generates. If it is C<< <= 0 >>, then a suitable default
448will be chosen (currently 6). 658will be chosen (currently 4).
449 659
450On error, the callback is called without arguments, otherwise it receives 660On error, the callback is called without arguments, otherwise it receives
451two array-refs with path-relative entry names. 661two array-refs with path-relative entry names.
452 662
453Example: 663Example:
… …
487as those tend to return 0 or 1 as link counts, which disables the 697as those tend to return 0 or 1 as link counts, which disables the
488directory counting heuristic. 698directory counting heuristic.
489 699
490=cut 700=cut
491 701
492sub aio_scandir($$$) { 702sub aio_scandir($$;$) {
703 aio_block {
493 my ($path, $maxreq, $cb) = @_; 704 my ($path, $maxreq, $cb) = @_;
494 705
495 my $pri = aioreq_pri; 706 my $pri = aioreq_pri;
496 707
497 my $grp = aio_group $cb; 708 my $grp = aio_group $cb;
498 709
499 $maxreq = 6 if $maxreq <= 0; 710 $maxreq = 4 if $maxreq <= 0;
500 711
501 # stat once 712 # stat once
502 aioreq_pri $pri;
503 add $grp aio_stat $path, sub {
504 return $grp->result () if $_[0];
505 my $now = time;
506 my $hash1 = join ":", (stat _)[0,1,3,7,9];
507
508 # read the directory entries
509 aioreq_pri $pri; 713 aioreq_pri $pri;
510 add $grp aio_readdir $path, sub { 714 add $grp aio_stat $path, sub {
511 my $entries = shift
512 or return $grp->result (); 715 return $grp->result () if $_[0];
716 my $now = time;
717 my $hash1 = join ":", (stat _)[0,1,3,7,9];
513 718
514 # stat the dir another time 719 # read the directory entries
515 aioreq_pri $pri; 720 aioreq_pri $pri;
721 add $grp aio_readdir $path, sub {
722 my $entries = shift
723 or return $grp->result ();
724
725 # stat the dir another time
726 aioreq_pri $pri;
516 add $grp aio_stat $path, sub { 727 add $grp aio_stat $path, sub {
517 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 728 my $hash2 = join ":", (stat _)[0,1,3,7,9];
518 729
519 my $ndirs; 730 my $ndirs;
520 731
521 # take the slow route if anything looks fishy 732 # take the slow route if anything looks fishy
522 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 733 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523 $ndirs = -1; 734 $ndirs = -1;
524 } else { 735 } else {
525 # if nlink == 2, we are finished 736 # if nlink == 2, we are finished
526 # on non-posix-fs's, we rely on nlink < 2 737 # on non-posix-fs's, we rely on nlink < 2
527 $ndirs = (stat _)[3] - 2 738 $ndirs = (stat _)[3] - 2
528 or return $grp->result ([], $entries); 739 or return $grp->result ([], $entries);
529 } 740 }
530 741
531 # sort into likely dirs and likely nondirs 742 # sort into likely dirs and likely nondirs
532 # dirs == files without ".", short entries first 743 # dirs == files without ".", short entries first
533 $entries = [map $_->[0], 744 $entries = [map $_->[0],
534 sort { $b->[1] cmp $a->[1] } 745 sort { $b->[1] cmp $a->[1] }
535 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 746 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536 @$entries]; 747 @$entries];
537 748
538 my (@dirs, @nondirs); 749 my (@dirs, @nondirs);
539 750
540 my $statgrp = add $grp aio_group sub { 751 my $statgrp = add $grp aio_group sub {
541 $grp->result (\@dirs, \@nondirs); 752 $grp->result (\@dirs, \@nondirs);
542 }; 753 };
543 754
544 limit $statgrp $maxreq; 755 limit $statgrp $maxreq;
545 feed $statgrp sub { 756 feed $statgrp sub {
546 return unless @$entries; 757 return unless @$entries;
547 my $entry = pop @$entries; 758 my $entry = pop @$entries;
548 759
549 aioreq_pri $pri; 760 aioreq_pri $pri;
550 add $statgrp aio_stat "$path/$entry/.", sub { 761 add $statgrp aio_stat "$path/$entry/.", sub {
551 if ($_[0] < 0) { 762 if ($_[0] < 0) {
552 push @nondirs, $entry; 763 push @nondirs, $entry;
553 } else { 764 } else {
554 # need to check for real directory 765 # need to check for real directory
555 aioreq_pri $pri; 766 aioreq_pri $pri;
556 add $statgrp aio_lstat "$path/$entry", sub { 767 add $statgrp aio_lstat "$path/$entry", sub {
557 if (-d _) { 768 if (-d _) {
558 push @dirs, $entry; 769 push @dirs, $entry;
559 770
560 unless (--$ndirs) { 771 unless (--$ndirs) {
561 push @nondirs, @$entries; 772 push @nondirs, @$entries;
562 feed $statgrp; 773 feed $statgrp;
774 }
775 } else {
776 push @nondirs, $entry;
563 } 777 }
564 } else {
565 push @nondirs, $entry;
566 } 778 }
567 } 779 }
568 } 780 };
569 }; 781 };
570 }; 782 };
571 }; 783 };
572 }; 784 };
785
786 $grp
573 }; 787 }
788}
574 789
790=item aio_rmtree $path, $callback->($status)
791
792Delete a directory tree starting (and including) C<$path>, return the
793status of the final C<rmdir> only. This is a composite request that
794uses C<aio_scandir> to recurse into and rmdir directories, and unlink
795everything else.
796
797=cut
798
799sub aio_rmtree;
800sub aio_rmtree($;$) {
801 aio_block {
802 my ($path, $cb) = @_;
803
804 my $pri = aioreq_pri;
805 my $grp = aio_group $cb;
806
807 aioreq_pri $pri;
808 add $grp aio_scandir $path, 0, sub {
809 my ($dirs, $nondirs) = @_;
810
811 my $dirgrp = aio_group sub {
812 add $grp aio_rmdir $path, sub {
813 $grp->result ($_[0]);
814 };
815 };
816
817 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
818 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
819
820 add $grp $dirgrp;
821 };
822
575 $grp 823 $grp
824 }
576} 825}
577 826
578=item aio_fsync $fh, $callback->($status) 827=item aio_fsync $fh, $callback->($status)
579 828
580Asynchronously call fsync on the given filehandle and call the callback 829Asynchronously call fsync on the given filehandle and call the callback
… …
794 1043
795=back 1044=back
796 1045
797=head2 SUPPORT FUNCTIONS 1046=head2 SUPPORT FUNCTIONS
798 1047
1048=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1049
799=over 4 1050=over 4
800 1051
801=item $fileno = IO::AIO::poll_fileno 1052=item $fileno = IO::AIO::poll_fileno
802 1053
803Return the I<request result pipe file descriptor>. This filehandle must be 1054Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 1058
808See C<poll_cb> for an example. 1059See C<poll_cb> for an example.
809 1060
810=item IO::AIO::poll_cb 1061=item IO::AIO::poll_cb
811 1062
812Process all outstanding events on the result pipe. You have to call this 1063Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1064regularly. Returns the number of events processed. Returns immediately
814when no events are outstanding. 1065when no events are outstanding. The amount of events processed depends on
1066the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1067
816If not all requests were processed for whatever reason, the filehandle 1068If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1069will still be ready when C<poll_cb> returns.
818 1070
819Example: Install an Event watcher that automatically calls 1071Example: Install an Event watcher that automatically calls
… …
821 1073
822 Event->io (fd => IO::AIO::poll_fileno, 1074 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1075 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1076 cb => \&IO::AIO::poll_cb);
825 1077
826=item IO::AIO::poll_some $max_requests 1078=item IO::AIO::max_poll_reqs $nreqs
827 1079
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1080=item IO::AIO::max_poll_time $seconds
829at a time.
830 1081
831Useful if you want to ensure some level of interactiveness when perl is 1082These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1083that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1084the maximum amount of time (default C<0>, meaning infinity) spent in
1085C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1086of time C<poll_cb> is allowed to use).
1087
1088Setting C<max_poll_time> to a non-zero value creates an overhead of one
1089syscall per request processed, which is not normally a problem unless your
1090callbacks are really really fast or your OS is really really slow (I am
1091not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1092
1093Setting these is useful if you want to ensure some level of
1094interactiveness when perl is not fast enough to process all requests in
1095time.
1096
1097For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1098
834Example: Install an Event watcher that automatically calls 1099Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1100IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1101program get the CPU sometimes even under high AIO load.
837 1102
1103 # try not to spend much more than 0.1s in poll_cb
1104 IO::AIO::max_poll_time 0.1;
1105
1106 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1107 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1108 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1109 cb => &IO::AIO::poll_cb);
841 1110
842=item IO::AIO::poll_wait 1111=item IO::AIO::poll_wait
843 1112
1113If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1114phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1115does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1116synchronously wait for some requests to finish).
847 1117
848See C<nreqs> for an example. 1118See C<nreqs> for an example.
849 1119
1120=item IO::AIO::poll
1121
1122Waits until some requests have been handled.
1123
1124Returns the number of requests processed, but is otherwise strictly
1125equivalent to:
1126
1127 IO::AIO::poll_wait, IO::AIO::poll_cb
1128
850=item IO::AIO::nreqs 1129=item IO::AIO::flush
851 1130
852Returns the number of requests currently in the ready, execute or pending 1131Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1132
855Example: wait till there are no outstanding requests anymore: 1133Strictly equivalent to:
856 1134
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1135 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1136 while IO::AIO::nreqs;
859 1137
860=item IO::AIO::nready 1138=back
861 1139
862Returns the number of requests currently in the ready state (not yet 1140=head3 CONTROLLING THE NUMBER OF THREADS
863executed).
864 1141
865=item IO::AIO::npending 1142=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 1143
888=item IO::AIO::min_parallel $nthreads 1144=item IO::AIO::min_parallel $nthreads
889 1145
890Set the minimum number of AIO threads to C<$nthreads>. The current 1146Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1147default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1148concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1149however, is unlimited).
894 1150
895IO::AIO starts threads only on demand, when an AIO request is queued and 1151IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1152no free thread exists. Please note that queueing up a hundred requests can
1153create demand for a hundred threads, even if it turns out that everything
1154is in the cache and could have been processed faster by a single thread.
897 1155
898It is recommended to keep the number of threads relatively low, as some 1156It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1157Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1158(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1159versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1173This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1174that all threads are killed and that there are no outstanding requests.
917 1175
918Under normal circumstances you don't need to call this function. 1176Under normal circumstances you don't need to call this function.
919 1177
1178=item IO::AIO::max_idle $nthreads
1179
1180Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1181threads that did not get a request to process within 10 seconds). That
1182means if a thread becomes idle while C<$nthreads> other threads are also
1183idle, it will free its resources and exit.
1184
1185This is useful when you allow a large number of threads (e.g. 100 or 1000)
1186to allow for extremely high load situations, but want to free resources
1187under normal circumstances (1000 threads can easily consume 30MB of RAM).
1188
1189The default is probably ok in most situations, especially if thread
1190creation is fast. If thread creation is very slow on your system you might
1191want to use larger values.
1192
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1193=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
921 1194
922This is a very bad function to use in interactive programs because it 1195This 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 1196blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1197use an C<aio_group> together with a feed callback.
… …
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1208C<max_oustsanding> is mainly useful in simple scripts (with low values) or
936as a stop gap to shield against fatal memory overflow (with large values). 1209as a stop gap to shield against fatal memory overflow (with large values).
937 1210
938=back 1211=back
939 1212
1213=head3 STATISTICAL INFORMATION
1214
1215=over
1216
1217=item IO::AIO::nreqs
1218
1219Returns the number of requests currently in the ready, execute or pending
1220states (i.e. for which their callback has not been invoked yet).
1221
1222Example: wait till there are no outstanding requests anymore:
1223
1224 IO::AIO::poll_wait, IO::AIO::poll_cb
1225 while IO::AIO::nreqs;
1226
1227=item IO::AIO::nready
1228
1229Returns the number of requests currently in the ready state (not yet
1230executed).
1231
1232=item IO::AIO::npending
1233
1234Returns the number of requests currently in the pending state (executed,
1235but not yet processed by poll_cb).
1236
1237=back
1238
940=cut 1239=cut
941 1240
942# support function to convert a fd into a perl filehandle 1241# support function to convert a fd into a perl filehandle
943sub _fd2fh { 1242sub _fd2fh {
944 return undef if $_[0] < 0; 1243 return undef if $_[0] < 0;
… …
955 *$sym 1254 *$sym
956} 1255}
957 1256
958min_parallel 8; 1257min_parallel 8;
959 1258
960END { 1259END { flush }
961 max_parallel 0;
962}
963 1260
9641; 12611;
965 1262
966=head2 FORK BEHAVIOUR 1263=head2 FORK BEHAVIOUR
967 1264

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