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Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC vs.
Revision 1.121 by root, Wed Apr 16 16:45:18 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
… …
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
30 # AnyEvent integration 31 # AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...)
31 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 32 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); 33 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35 # EV integration
36 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
33 37
34 # Event integration 38 # Event integration
35 Event->io (fd => IO::AIO::poll_fileno, 39 Event->io (fd => IO::AIO::poll_fileno,
36 poll => 'r', 40 poll => 'r',
37 cb => \&IO::AIO::poll_cb); 41 cb => \&IO::AIO::poll_cb);
… …
50 54
51=head1 DESCRIPTION 55=head1 DESCRIPTION
52 56
53This module implements asynchronous I/O using whatever means your 57This module implements asynchronous I/O using whatever means your
54operating system supports. 58operating system supports.
59
60Asynchronous means that operations that can normally block your program
61(e.g. reading from disk) will be done asynchronously: the operation
62will still block, but you can do something else in the meantime. This
63is extremely useful for programs that need to stay interactive even
64when doing heavy I/O (GUI programs, high performance network servers
65etc.), but can also be used to easily do operations in parallel that are
66normally done sequentially, e.g. stat'ing many files, which is much faster
67on a RAID volume or over NFS when you do a number of stat operations
68concurrently.
69
70While most of this works on all types of file descriptors (for
71example sockets), using these functions on file descriptors that
72support nonblocking operation (again, sockets, pipes etc.) is very
73inefficient. Use an event loop for that (such as the L<Event|Event>
74module): IO::AIO will naturally fit into such an event loop itself.
55 75
56In this version, a number of threads are started that execute your 76In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 77requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 78in 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 79to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 80functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 81not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 82files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 83aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 84using threads anyway.
65 85
66Although the module will work with in the presence of other (Perl-) 86Although the module will work in the presence of other (Perl-) threads,
67threads, it is currently not reentrant in any way, so use appropriate 87it is currently not reentrant in any way, so use appropriate locking
68locking yourself, always call C<poll_cb> from within the same thread, or 88yourself, always call C<poll_cb> from within the same thread, or never
69never call C<poll_cb> (or other C<aio_> functions) recursively. 89call C<poll_cb> (or other C<aio_> functions) recursively.
90
91=head2 EXAMPLE
92
93This is a simple example that uses the Event module and loads
94F</etc/passwd> asynchronously:
95
96 use Fcntl;
97 use Event;
98 use IO::AIO;
99
100 # register the IO::AIO callback with Event
101 Event->io (fd => IO::AIO::poll_fileno,
102 poll => 'r',
103 cb => \&IO::AIO::poll_cb);
104
105 # queue the request to open /etc/passwd
106 aio_open "/etc/passwd", O_RDONLY, 0, sub {
107 my $fh = shift
108 or die "error while opening: $!";
109
110 # stat'ing filehandles is generally non-blocking
111 my $size = -s $fh;
112
113 # queue a request to read the file
114 my $contents;
115 aio_read $fh, 0, $size, $contents, 0, sub {
116 $_[0] == $size
117 or die "short read: $!";
118
119 close $fh;
120
121 # file contents now in $contents
122 print $contents;
123
124 # exit event loop and program
125 Event::unloop;
126 };
127 };
128
129 # possibly queue up other requests, or open GUI windows,
130 # check for sockets etc. etc.
131
132 # process events as long as there are some:
133 Event::loop;
70 134
71=head1 REQUEST ANATOMY AND LIFETIME 135=head1 REQUEST ANATOMY AND LIFETIME
72 136
73Every C<aio_*> function creates a request. which is a C data structure not 137Every C<aio_*> function creates a request. which is a C data structure not
74directly visible to Perl. 138directly visible to Perl.
… …
116Request has reached the end of its lifetime and holds no resources anymore 180Request 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 181(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 182aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 183result in a runtime error).
120 184
185=back
186
121=cut 187=cut
122 188
123package IO::AIO; 189package IO::AIO;
190
191use Carp ();
124 192
125no warnings; 193no warnings;
126use strict 'vars'; 194use strict 'vars';
127 195
128use base 'Exporter'; 196use base 'Exporter';
129 197
130BEGIN { 198BEGIN {
131 our $VERSION = '2.0'; 199 our $VERSION = '2.61';
132 200
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 201 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 202 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 203 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136 aio_group aio_nop); 204 aio_fdatasync aio_pathsync aio_readahead
205 aio_rename aio_link aio_move aio_copy aio_group
206 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
207 aio_chmod aio_utime aio_truncate);
208
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 209 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 210 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 211 min_parallel max_parallel max_idle
212 nreqs nready npending nthreads
213 max_poll_time max_poll_reqs);
140 214
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 216
143 require XSLoader; 217 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 218 XSLoader::load ("IO::AIO", $VERSION);
145} 219}
146 220
147=head1 FUNCTIONS 221=head1 FUNCTIONS
148 222
149=head2 AIO FUNCTIONS 223=head2 AIO REQUEST FUNCTIONS
150 224
151All the C<aio_*> calls are more or less thin wrappers around the syscall 225All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 226with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 227and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 228which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 231syscall has been executed asynchronously.
158 232
159All functions expecting a filehandle keep a copy of the filehandle 233All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 234internally until the request has finished.
161 235
162All requests return objects of type L<IO::AIO::REQ> that allow further 236All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 237further manipulation of those requests while they are in-flight.
164 238
165The pathnames you pass to these routines I<must> be absolute and 239The 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 240encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 241request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 242changed. Alternatively, you can make sure that you never change the
169current working directory. 243current working directory anywhere in the program and then use relative
244paths.
170 245
171To encode pathnames to byte form, either make sure you either: a) 246To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 247in 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 248tinkering, 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 249your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 250environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 251use something else to ensure your scalar has the correct contents.
252
253This works, btw. independent of the internal UTF-8 bit, which IO::AIO
254handles correctly wether it is set or not.
177 255
178=over 4 256=over 4
179 257
180=item $prev_pri = aioreq_pri [$pri] 258=item $prev_pri = aioreq_pri [$pri]
181 259
… …
201 aio_read $_[0], ..., sub { 279 aio_read $_[0], ..., sub {
202 ... 280 ...
203 }; 281 };
204 }; 282 };
205 283
284
206=item aioreq_nice $pri_adjust 285=item aioreq_nice $pri_adjust
207 286
208Similar to C<aioreq_pri>, but subtracts the given value from the current 287Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 288priority, so the effect is cumulative.
289
210 290
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 291=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 292
213Asynchronously open or create a file and call the callback with a newly 293Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 294created filehandle for the file.
… …
220list. They are the same as used by C<sysopen>. 300list. They are the same as used by C<sysopen>.
221 301
222Likewise, C<$mode> specifies the mode of the newly created file, if it 302Likewise, C<$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>, 303didn'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, 304except 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). 305and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
306by the umask in effect then the request is being executed, so better never
307change the umask.
226 308
227Example: 309Example:
228 310
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 311 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 312 if ($_[0]) {
… …
233 } else { 315 } else {
234 die "open failed: $!\n"; 316 die "open failed: $!\n";
235 } 317 }
236 }; 318 };
237 319
320
238=item aio_close $fh, $callback->($status) 321=item aio_close $fh, $callback->($status)
239 322
240Asynchronously close a file and call the callback with the result 323Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 324code.
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.
245 325
246This is supposed to be a bug in the API, so that might change. It's 326Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247therefore best to avoid this function. 327closing the file descriptor associated with the filehandle itself.
328
329Therefore, C<aio_close> will not close the filehandle - instead it will
330use dup2 to overwrite the file descriptor with the write-end of a pipe
331(the pipe fd will be created on demand and will be cached).
332
333Or in other words: the file descriptor will be closed, but it will not be
334free for reuse until the perl filehandle is closed.
335
336=cut
248 337
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 339
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 341
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 342Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254into the scalar given by C<data> and offset C<dataoffset> and calls the 343into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255callback without the actual number of bytes read (or -1 on error, just 344callback without the actual number of bytes read (or -1 on error, just
256like the syscall). 345like the syscall).
257 346
347If C<$offset> is undefined, then the current file descriptor offset will
348be used (and updated), otherwise the file descriptor offset will not be
349changed by these calls.
350
351If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
352
353If C<$dataoffset> is less than zero, it will be counted from the end of
354C<$data>.
355
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 356The C<$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 357is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 358the necessary/optional hardware is installed).
261 359
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 360Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 361offset C<0> within the scalar:
264 362
265 aio_read $fh, 7, 15, $buffer, 0, sub { 363 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 364 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 365 print "read $_[0] bytes: <$buffer>\n";
268 }; 366 };
269 367
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}
344 368
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 369=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 370
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 371Tries 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 372reading 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 386C<$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 387bytes 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 388provides 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 389value equals C<$length> one can assume that C<$length> bytes have been
366read. 390read.
391
367 392
368=item aio_readahead $fh,$offset,$length, $callback->($retval) 393=item aio_readahead $fh,$offset,$length, $callback->($retval)
369 394
370C<aio_readahead> populates the page cache with data from a file so that 395C<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> 396subsequent 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. 402file. The current file offset of the file is left unchanged.
378 403
379If that syscall doesn't exist (likely if your OS isn't Linux) it will be 404If 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. 405emulated by simply reading the data, which would have a similar effect.
381 406
407
382=item aio_stat $fh_or_path, $callback->($status) 408=item aio_stat $fh_or_path, $callback->($status)
383 409
384=item aio_lstat $fh, $callback->($status) 410=item aio_lstat $fh, $callback->($status)
385 411
386Works like perl's C<stat> or C<lstat> in void context. The callback will 412Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
399 aio_stat "/etc/passwd", sub { 425 aio_stat "/etc/passwd", sub {
400 $_[0] and die "stat failed: $!"; 426 $_[0] and die "stat failed: $!";
401 print "size is ", -s _, "\n"; 427 print "size is ", -s _, "\n";
402 }; 428 };
403 429
430
431=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
432
433Works like perl's C<utime> function (including the special case of $atime
434and $mtime being undef). Fractional times are supported if the underlying
435syscalls support them.
436
437When called with a pathname, uses utimes(2) if available, otherwise
438utime(2). If called on a file descriptor, uses futimes(2) if available,
439otherwise returns ENOSYS, so this is not portable.
440
441Examples:
442
443 # set atime and mtime to current time (basically touch(1)):
444 aio_utime "path", undef, undef;
445 # set atime to current time and mtime to beginning of the epoch:
446 aio_utime "path", time, undef; # undef==0
447
448
449=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
450
451Works like perl's C<chown> function, except that C<undef> for either $uid
452or $gid is being interpreted as "do not change" (but -1 can also be used).
453
454Examples:
455
456 # same as "chown root path" in the shell:
457 aio_chown "path", 0, -1;
458 # same as above:
459 aio_chown "path", 0, undef;
460
461
462=item aio_truncate $fh_or_path, $offset, $callback->($status)
463
464Works like truncate(2) or ftruncate(2).
465
466
467=item aio_chmod $fh_or_path, $mode, $callback->($status)
468
469Works like perl's C<chmod> function.
470
471
404=item aio_unlink $pathname, $callback->($status) 472=item aio_unlink $pathname, $callback->($status)
405 473
406Asynchronously unlink (delete) a file and call the callback with the 474Asynchronously unlink (delete) a file and call the callback with the
407result code. 475result code.
408 476
477
478=item aio_mknod $path, $mode, $dev, $callback->($status)
479
480[EXPERIMENTAL]
481
482Asynchronously create a device node (or fifo). See mknod(2).
483
484The only (POSIX-) portable way of calling this function is:
485
486 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
487
488
409=item aio_link $srcpath, $dstpath, $callback->($status) 489=item aio_link $srcpath, $dstpath, $callback->($status)
410 490
411Asynchronously create a new link to the existing object at C<$srcpath> at 491Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 492the path C<$dstpath> and call the callback with the result code.
413 493
494
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 495=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 496
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 497Asynchronously 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. 498the path C<$dstpath> and call the callback with the result code.
418 499
500
501=item aio_readlink $path, $callback->($link)
502
503Asynchronously read the symlink specified by C<$path> and pass it to
504the callback. If an error occurs, nothing or undef gets passed to the
505callback.
506
507
419=item aio_rename $srcpath, $dstpath, $callback->($status) 508=item aio_rename $srcpath, $dstpath, $callback->($status)
420 509
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 510Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 511rename(2) and call the callback with the result code.
423 512
513
514=item aio_mkdir $pathname, $mode, $callback->($status)
515
516Asynchronously mkdir (create) a directory and call the callback with
517the result code. C<$mode> will be modified by the umask at the time the
518request is executed, so do not change your umask.
519
520
424=item aio_rmdir $pathname, $callback->($status) 521=item aio_rmdir $pathname, $callback->($status)
425 522
426Asynchronously rmdir (delete) a directory and call the callback with the 523Asynchronously rmdir (delete) a directory and call the callback with the
427result code. 524result code.
525
428 526
429=item aio_readdir $pathname, $callback->($entries) 527=item aio_readdir $pathname, $callback->($entries)
430 528
431Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 529Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432directory (i.e. opendir + readdir + closedir). The entries will not be 530directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 531sorted, and will B<NOT> include the C<.> and C<..> entries.
434 532
435The callback a single argument which is either C<undef> or an array-ref 533The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 534with the filenames.
535
536
537=item aio_load $path, $data, $callback->($status)
538
539This is a composite request that tries to fully load the given file into
540memory. Status is the same as with aio_read.
541
542=cut
543
544sub aio_load($$;$) {
545 aio_block {
546 my ($path, undef, $cb) = @_;
547 my $data = \$_[1];
548
549 my $pri = aioreq_pri;
550 my $grp = aio_group $cb;
551
552 aioreq_pri $pri;
553 add $grp aio_open $path, O_RDONLY, 0, sub {
554 my $fh = shift
555 or return $grp->result (-1);
556
557 aioreq_pri $pri;
558 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
559 $grp->result ($_[0]);
560 };
561 };
562
563 $grp
564 }
565}
566
567=item aio_copy $srcpath, $dstpath, $callback->($status)
568
569Try to copy the I<file> (directories not supported as either source or
570destination) from C<$srcpath> to C<$dstpath> and call the callback with
571the C<0> (error) or C<-1> ok.
572
573This is a composite request that it creates the destination file with
574mode 0200 and copies the contents of the source file into it using
575C<aio_sendfile>, followed by restoring atime, mtime, access mode and
576uid/gid, in that order.
577
578If an error occurs, the partial destination file will be unlinked, if
579possible, except when setting atime, mtime, access mode and uid/gid, where
580errors are being ignored.
581
582=cut
583
584sub aio_copy($$;$) {
585 aio_block {
586 my ($src, $dst, $cb) = @_;
587
588 my $pri = aioreq_pri;
589 my $grp = aio_group $cb;
590
591 aioreq_pri $pri;
592 add $grp aio_open $src, O_RDONLY, 0, sub {
593 if (my $src_fh = $_[0]) {
594 my @stat = stat $src_fh;
595
596 aioreq_pri $pri;
597 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
598 if (my $dst_fh = $_[0]) {
599 aioreq_pri $pri;
600 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
601 if ($_[0] == $stat[7]) {
602 $grp->result (0);
603 close $src_fh;
604
605 # those should not normally block. should. should.
606 utime $stat[8], $stat[9], $dst;
607 chmod $stat[2] & 07777, $dst_fh;
608 chown $stat[4], $stat[5], $dst_fh;
609
610 aioreq_pri $pri;
611 add $grp aio_close $dst_fh;
612 } else {
613 $grp->result (-1);
614 close $src_fh;
615 close $dst_fh;
616
617 aioreq $pri;
618 add $grp aio_unlink $dst;
619 }
620 };
621 } else {
622 $grp->result (-1);
623 }
624 },
625
626 } else {
627 $grp->result (-1);
628 }
629 };
630
631 $grp
632 }
633}
634
635=item aio_move $srcpath, $dstpath, $callback->($status)
636
637Try to move the I<file> (directories not supported as either source or
638destination) from C<$srcpath> to C<$dstpath> and call the callback with
639the C<0> (error) or C<-1> ok.
640
641This is a composite request that tries to rename(2) the file first. If
642rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
643that is successful, unlinking the C<$srcpath>.
644
645=cut
646
647sub aio_move($$;$) {
648 aio_block {
649 my ($src, $dst, $cb) = @_;
650
651 my $pri = aioreq_pri;
652 my $grp = aio_group $cb;
653
654 aioreq_pri $pri;
655 add $grp aio_rename $src, $dst, sub {
656 if ($_[0] && $! == EXDEV) {
657 aioreq_pri $pri;
658 add $grp aio_copy $src, $dst, sub {
659 $grp->result ($_[0]);
660
661 if (!$_[0]) {
662 aioreq_pri $pri;
663 add $grp aio_unlink $src;
664 }
665 };
666 } else {
667 $grp->result ($_[0]);
668 }
669 };
670
671 $grp
672 }
673}
437 674
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 675=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 676
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 677Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 678efficiently separate the entries of directory C<$path> into two sets of
… …
487as those tend to return 0 or 1 as link counts, which disables the 724as those tend to return 0 or 1 as link counts, which disables the
488directory counting heuristic. 725directory counting heuristic.
489 726
490=cut 727=cut
491 728
492sub aio_scandir($$$) { 729sub aio_scandir($$;$) {
730 aio_block {
493 my ($path, $maxreq, $cb) = @_; 731 my ($path, $maxreq, $cb) = @_;
494 732
495 my $pri = aioreq_pri; 733 my $pri = aioreq_pri;
496 734
497 my $grp = aio_group $cb; 735 my $grp = aio_group $cb;
498 736
499 $maxreq = 4 if $maxreq <= 0; 737 $maxreq = 4 if $maxreq <= 0;
500 738
501 # stat once 739 # 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; 740 aioreq_pri $pri;
510 add $grp aio_readdir $path, sub { 741 add $grp aio_stat $path, sub {
511 my $entries = shift
512 or return $grp->result (); 742 return $grp->result () if $_[0];
743 my $now = time;
744 my $hash1 = join ":", (stat _)[0,1,3,7,9];
513 745
514 # stat the dir another time 746 # read the directory entries
515 aioreq_pri $pri; 747 aioreq_pri $pri;
748 add $grp aio_readdir $path, sub {
749 my $entries = shift
750 or return $grp->result ();
751
752 # stat the dir another time
753 aioreq_pri $pri;
516 add $grp aio_stat $path, sub { 754 add $grp aio_stat $path, sub {
517 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 755 my $hash2 = join ":", (stat _)[0,1,3,7,9];
518 756
519 my $ndirs; 757 my $ndirs;
520 758
521 # take the slow route if anything looks fishy 759 # take the slow route if anything looks fishy
522 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 760 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523 $ndirs = -1; 761 $ndirs = -1;
524 } else { 762 } else {
525 # if nlink == 2, we are finished 763 # if nlink == 2, we are finished
526 # on non-posix-fs's, we rely on nlink < 2 764 # on non-posix-fs's, we rely on nlink < 2
527 $ndirs = (stat _)[3] - 2 765 $ndirs = (stat _)[3] - 2
528 or return $grp->result ([], $entries); 766 or return $grp->result ([], $entries);
529 } 767 }
530 768
531 # sort into likely dirs and likely nondirs 769 # sort into likely dirs and likely nondirs
532 # dirs == files without ".", short entries first 770 # dirs == files without ".", short entries first
533 $entries = [map $_->[0], 771 $entries = [map $_->[0],
534 sort { $b->[1] cmp $a->[1] } 772 sort { $b->[1] cmp $a->[1] }
535 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 773 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536 @$entries]; 774 @$entries];
537 775
538 my (@dirs, @nondirs); 776 my (@dirs, @nondirs);
539 777
540 my $statgrp = add $grp aio_group sub { 778 my $statgrp = add $grp aio_group sub {
541 $grp->result (\@dirs, \@nondirs); 779 $grp->result (\@dirs, \@nondirs);
542 }; 780 };
543 781
544 limit $statgrp $maxreq; 782 limit $statgrp $maxreq;
545 feed $statgrp sub { 783 feed $statgrp sub {
546 return unless @$entries; 784 return unless @$entries;
547 my $entry = pop @$entries; 785 my $entry = pop @$entries;
548 786
549 aioreq_pri $pri; 787 aioreq_pri $pri;
550 add $statgrp aio_stat "$path/$entry/.", sub { 788 add $statgrp aio_stat "$path/$entry/.", sub {
551 if ($_[0] < 0) { 789 if ($_[0] < 0) {
552 push @nondirs, $entry; 790 push @nondirs, $entry;
553 } else { 791 } else {
554 # need to check for real directory 792 # need to check for real directory
555 aioreq_pri $pri; 793 aioreq_pri $pri;
556 add $statgrp aio_lstat "$path/$entry", sub { 794 add $statgrp aio_lstat "$path/$entry", sub {
557 if (-d _) { 795 if (-d _) {
558 push @dirs, $entry; 796 push @dirs, $entry;
559 797
560 unless (--$ndirs) { 798 unless (--$ndirs) {
561 push @nondirs, @$entries; 799 push @nondirs, @$entries;
562 feed $statgrp; 800 feed $statgrp;
801 }
802 } else {
803 push @nondirs, $entry;
563 } 804 }
564 } else {
565 push @nondirs, $entry;
566 } 805 }
567 } 806 }
568 } 807 };
569 }; 808 };
570 }; 809 };
571 }; 810 };
572 }; 811 };
812
813 $grp
573 }; 814 }
574
575 $grp
576} 815}
816
817=item aio_rmtree $path, $callback->($status)
818
819Delete a directory tree starting (and including) C<$path>, return the
820status of the final C<rmdir> only. This is a composite request that
821uses C<aio_scandir> to recurse into and rmdir directories, and unlink
822everything else.
823
824=cut
825
826sub aio_rmtree;
827sub aio_rmtree($;$) {
828 aio_block {
829 my ($path, $cb) = @_;
830
831 my $pri = aioreq_pri;
832 my $grp = aio_group $cb;
833
834 aioreq_pri $pri;
835 add $grp aio_scandir $path, 0, sub {
836 my ($dirs, $nondirs) = @_;
837
838 my $dirgrp = aio_group sub {
839 add $grp aio_rmdir $path, sub {
840 $grp->result ($_[0]);
841 };
842 };
843
844 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
845 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
846
847 add $grp $dirgrp;
848 };
849
850 $grp
851 }
852}
853
854=item aio_sync $callback->($status)
855
856Asynchronously call sync and call the callback when finished.
577 857
578=item aio_fsync $fh, $callback->($status) 858=item aio_fsync $fh, $callback->($status)
579 859
580Asynchronously call fsync on the given filehandle and call the callback 860Asynchronously call fsync on the given filehandle and call the callback
581with the fsync result code. 861with the fsync result code.
… …
585Asynchronously call fdatasync on the given filehandle and call the 865Asynchronously call fdatasync on the given filehandle and call the
586callback with the fdatasync result code. 866callback with the fdatasync result code.
587 867
588If this call isn't available because your OS lacks it or it couldn't be 868If 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. 869detected, it will be emulated by calling C<fsync> instead.
870
871=item aio_pathsync $path, $callback->($status)
872
873This request tries to open, fsync and close the given path. This is a
874composite request intended tosync directories after directory operations
875(E.g. rename). This might not work on all operating systems or have any
876specific effect, but usually it makes sure that directory changes get
877written to disc. It works for anything that can be opened for read-only,
878not just directories.
879
880Passes C<0> when everything went ok, and C<-1> on error.
881
882=cut
883
884sub aio_pathsync($;$) {
885 aio_block {
886 my ($path, $cb) = @_;
887
888 my $pri = aioreq_pri;
889 my $grp = aio_group $cb;
890
891 aioreq_pri $pri;
892 add $grp aio_open $path, O_RDONLY, 0, sub {
893 my ($fh) = @_;
894 if ($fh) {
895 aioreq_pri $pri;
896 add $grp aio_fsync $fh, sub {
897 $grp->result ($_[0]);
898
899 aioreq_pri $pri;
900 add $grp aio_close $fh;
901 };
902 } else {
903 $grp->result (-1);
904 }
905 };
906
907 $grp
908 }
909}
590 910
591=item aio_group $callback->(...) 911=item aio_group $callback->(...)
592 912
593This is a very special aio request: Instead of doing something, it is a 913This 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 914container for other aio requests, which is useful if you want to bundle
… …
731itself. Useful when you queued a lot of events but got a result early. 1051itself. Useful when you queued a lot of events but got a result early.
732 1052
733=item $grp->result (...) 1053=item $grp->result (...)
734 1054
735Set the result value(s) that will be passed to the group callback when all 1055Set 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 1056subrequests have finished and set the groups errno to the current value
737of errno (just like calling C<errno> without an error number). By default, 1057of errno (just like calling C<errno> without an error number). By default,
738no argument will be passed and errno is zero. 1058no argument will be passed and errno is zero.
739 1059
740=item $grp->errno ([$errno]) 1060=item $grp->errno ([$errno])
741 1061
… …
794 1114
795=back 1115=back
796 1116
797=head2 SUPPORT FUNCTIONS 1117=head2 SUPPORT FUNCTIONS
798 1118
1119=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1120
799=over 4 1121=over 4
800 1122
801=item $fileno = IO::AIO::poll_fileno 1123=item $fileno = IO::AIO::poll_fileno
802 1124
803Return the I<request result pipe file descriptor>. This filehandle must be 1125Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 1129
808See C<poll_cb> for an example. 1130See C<poll_cb> for an example.
809 1131
810=item IO::AIO::poll_cb 1132=item IO::AIO::poll_cb
811 1133
812Process all outstanding events on the result pipe. You have to call this 1134Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1135regularly. Returns the number of events processed. Returns immediately
814when no events are outstanding. 1136when no events are outstanding. The amount of events processed depends on
1137the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1138
816If not all requests were processed for whatever reason, the filehandle 1139If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1140will still be ready when C<poll_cb> returns.
818 1141
819Example: Install an Event watcher that automatically calls 1142Example: Install an Event watcher that automatically calls
… …
821 1144
822 Event->io (fd => IO::AIO::poll_fileno, 1145 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1146 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1147 cb => \&IO::AIO::poll_cb);
825 1148
826=item IO::AIO::poll_some $max_requests 1149=item IO::AIO::max_poll_reqs $nreqs
827 1150
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1151=item IO::AIO::max_poll_time $seconds
829at a time.
830 1152
831Useful if you want to ensure some level of interactiveness when perl is 1153These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1154that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1155the maximum amount of time (default C<0>, meaning infinity) spent in
1156C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1157of time C<poll_cb> is allowed to use).
1158
1159Setting C<max_poll_time> to a non-zero value creates an overhead of one
1160syscall per request processed, which is not normally a problem unless your
1161callbacks are really really fast or your OS is really really slow (I am
1162not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1163
1164Setting these is useful if you want to ensure some level of
1165interactiveness when perl is not fast enough to process all requests in
1166time.
1167
1168For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1169
834Example: Install an Event watcher that automatically calls 1170Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1171IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1172program get the CPU sometimes even under high AIO load.
837 1173
1174 # try not to spend much more than 0.1s in poll_cb
1175 IO::AIO::max_poll_time 0.1;
1176
1177 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1178 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1179 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1180 cb => &IO::AIO::poll_cb);
841 1181
842=item IO::AIO::poll_wait 1182=item IO::AIO::poll_wait
843 1183
1184If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1185phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1186does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1187synchronously wait for some requests to finish).
847 1188
848See C<nreqs> for an example. 1189See C<nreqs> for an example.
849 1190
1191=item IO::AIO::poll
1192
1193Waits until some requests have been handled.
1194
1195Returns the number of requests processed, but is otherwise strictly
1196equivalent to:
1197
1198 IO::AIO::poll_wait, IO::AIO::poll_cb
1199
850=item IO::AIO::nreqs 1200=item IO::AIO::flush
851 1201
852Returns the number of requests currently in the ready, execute or pending 1202Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1203
855Example: wait till there are no outstanding requests anymore: 1204Strictly equivalent to:
856 1205
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1206 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1207 while IO::AIO::nreqs;
859 1208
860=item IO::AIO::nready 1209=back
861 1210
862Returns the number of requests currently in the ready state (not yet 1211=head3 CONTROLLING THE NUMBER OF THREADS
863executed).
864 1212
865=item IO::AIO::npending 1213=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 1214
888=item IO::AIO::min_parallel $nthreads 1215=item IO::AIO::min_parallel $nthreads
889 1216
890Set the minimum number of AIO threads to C<$nthreads>. The current 1217Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1218default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1219concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1220however, is unlimited).
894 1221
895IO::AIO starts threads only on demand, when an AIO request is queued and 1222IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1223no free thread exists. Please note that queueing up a hundred requests can
1224create demand for a hundred threads, even if it turns out that everything
1225is in the cache and could have been processed faster by a single thread.
897 1226
898It is recommended to keep the number of threads relatively low, as some 1227It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1228Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1229(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1230versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1244This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1245that all threads are killed and that there are no outstanding requests.
917 1246
918Under normal circumstances you don't need to call this function. 1247Under normal circumstances you don't need to call this function.
919 1248
1249=item IO::AIO::max_idle $nthreads
1250
1251Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1252threads that did not get a request to process within 10 seconds). That
1253means if a thread becomes idle while C<$nthreads> other threads are also
1254idle, it will free its resources and exit.
1255
1256This is useful when you allow a large number of threads (e.g. 100 or 1000)
1257to allow for extremely high load situations, but want to free resources
1258under normal circumstances (1000 threads can easily consume 30MB of RAM).
1259
1260The default is probably ok in most situations, especially if thread
1261creation is fast. If thread creation is very slow on your system you might
1262want to use larger values.
1263
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1264=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
921 1265
922This is a very bad function to use in interactive programs because it 1266This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1267blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1268use an C<aio_group> together with a feed callback.
925 1269
926Sets the maximum number of outstanding requests to C<$nreqs>. If you 1270Sets 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 1271do 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>) 1272C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
929function will block until the limit is no longer exceeded. 1273function will block until the limit is no longer exceeded.
930 1274
931The default value is very large, so there is no practical limit on the 1275The default value is very large, so there is no practical limit on the
932number of outstanding requests. 1276number of outstanding requests.
… …
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1279C<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). 1280as a stop gap to shield against fatal memory overflow (with large values).
937 1281
938=back 1282=back
939 1283
1284=head3 STATISTICAL INFORMATION
1285
1286=over
1287
1288=item IO::AIO::nreqs
1289
1290Returns the number of requests currently in the ready, execute or pending
1291states (i.e. for which their callback has not been invoked yet).
1292
1293Example: wait till there are no outstanding requests anymore:
1294
1295 IO::AIO::poll_wait, IO::AIO::poll_cb
1296 while IO::AIO::nreqs;
1297
1298=item IO::AIO::nready
1299
1300Returns the number of requests currently in the ready state (not yet
1301executed).
1302
1303=item IO::AIO::npending
1304
1305Returns the number of requests currently in the pending state (executed,
1306but not yet processed by poll_cb).
1307
1308=back
1309
940=cut 1310=cut
941 1311
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; 1312min_parallel 8;
1313
1314END { flush }
959 1315
9601; 13161;
961 1317
962=head2 FORK BEHAVIOUR 1318=head2 FORK BEHAVIOUR
963 1319
… …
983bytes of memory. In addition, stat requests need a stat buffer (possibly 1339bytes of memory. In addition, stat requests need a stat buffer (possibly
984a few hundred bytes), readdir requires a result buffer and so on. Perl 1340a 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 1341scalars and other data passed into aio requests will also be locked and
986will consume memory till the request has entered the done state. 1342will consume memory till the request has entered the done state.
987 1343
988This is now awfully much, so queuing lots of requests is not usually a 1344This is not awfully much, so queuing lots of requests is not usually a
989problem. 1345problem.
990 1346
991Per-thread usage: 1347Per-thread usage:
992 1348
993In the execution phase, some aio requests require more memory for 1349In the execution phase, some aio requests require more memory for

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