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Revision 1.80 by root, Thu Oct 26 16:28:33 2006 UTC vs.
Revision 1.119 by root, Sun Dec 2 20:54:33 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
… …
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 = '2.6';
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 aio_stat
134 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 202 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 203 aio_readlink aio_sync aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
136 aio_group aio_nop); 204 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
205 aio_chown aio_chmod aio_utime aio_truncate);
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 206 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 207 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs nready npending); 208 min_parallel max_parallel max_idle
209 nreqs nready npending nthreads
210 max_poll_time max_poll_reqs);
140 211
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 212 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 213
143 require XSLoader; 214 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 215 XSLoader::load ("IO::AIO", $VERSION);
145} 216}
146 217
147=head1 FUNCTIONS 218=head1 FUNCTIONS
148 219
149=head2 AIO FUNCTIONS 220=head2 AIO REQUEST FUNCTIONS
150 221
151All the C<aio_*> calls are more or less thin wrappers around the syscall 222All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 223with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 224and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 225which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 228syscall has been executed asynchronously.
158 229
159All functions expecting a filehandle keep a copy of the filehandle 230All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 231internally until the request has finished.
161 232
162All requests return objects of type L<IO::AIO::REQ> that allow further 233All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 234further manipulation of those requests while they are in-flight.
164 235
165The pathnames you pass to these routines I<must> be absolute and 236The 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 237encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 238request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 239changed. Alternatively, you can make sure that you never change the
169current working directory. 240current working directory anywhere in the program and then use relative
241paths.
170 242
171To encode pathnames to byte form, either make sure you either: a) 243To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 244in 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 245tinkering, 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 246your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 247environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 248use something else to ensure your scalar has the correct contents.
249
250This works, btw. independent of the internal UTF-8 bit, which IO::AIO
251handles correctly wether it is set or not.
177 252
178=over 4 253=over 4
179 254
180=item $prev_pri = aioreq_pri [$pri] 255=item $prev_pri = aioreq_pri [$pri]
181 256
… …
201 aio_read $_[0], ..., sub { 276 aio_read $_[0], ..., sub {
202 ... 277 ...
203 }; 278 };
204 }; 279 };
205 280
281
206=item aioreq_nice $pri_adjust 282=item aioreq_nice $pri_adjust
207 283
208Similar to C<aioreq_pri>, but subtracts the given value from the current 284Similar to C<aioreq_pri>, but subtracts the given value from the current
209priority, so effects are cumulative. 285priority, so the effect is cumulative.
286
210 287
211=item aio_open $pathname, $flags, $mode, $callback->($fh) 288=item aio_open $pathname, $flags, $mode, $callback->($fh)
212 289
213Asynchronously open or create a file and call the callback with a newly 290Asynchronously open or create a file and call the callback with a newly
214created filehandle for the file. 291created filehandle for the file.
… …
220list. They are the same as used by C<sysopen>. 297list. They are the same as used by C<sysopen>.
221 298
222Likewise, C<$mode> specifies the mode of the newly created file, if it 299Likewise, C<$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>, 300didn'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, 301except 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). 302and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
303by the umask in effect then the request is being executed, so better never
304change the umask.
226 305
227Example: 306Example:
228 307
229 aio_open "/etc/passwd", O_RDONLY, 0, sub { 308 aio_open "/etc/passwd", O_RDONLY, 0, sub {
230 if ($_[0]) { 309 if ($_[0]) {
… …
233 } else { 312 } else {
234 die "open failed: $!\n"; 313 die "open failed: $!\n";
235 } 314 }
236 }; 315 };
237 316
317
238=item aio_close $fh, $callback->($status) 318=item aio_close $fh, $callback->($status)
239 319
240Asynchronously close a file and call the callback with the result 320Asynchronously close a file and call the callback with the result
241code. I<WARNING:> although accepted, you should not pass in a perl 321code.
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.
245 322
246This is supposed to be a bug in the API, so that might change. It's 323Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247therefore best to avoid this function. 324closing the file descriptor associated with the filehandle itself. Here is
325what aio_close will try:
326
327 1. dup()licate the fd
328 2. asynchronously close() the duplicated fd
329 3. dup()licate the fd once more
330 4. let perl close() the filehandle
331 5. asynchronously close the duplicated fd
332
333The idea is that the first close() flushes stuff to disk that closing an
334fd will flush, so when perl closes the fd, nothing much will need to be
335flushed. The second async. close() will then flush stuff to disk that
336closing the last fd to the file will flush.
337
338Just FYI, SuSv3 has this to say on close:
339
340 All outstanding record locks owned by the process on the file
341 associated with the file descriptor shall be removed.
342
343 If fildes refers to a socket, close() shall cause the socket to be
344 destroyed. ... close() shall block for up to the current linger
345 interval until all data is transmitted.
346 [this actually sounds like a specification bug, but who knows]
347
348And at least Linux additionally actually flushes stuff on every close,
349even when the file itself is still open.
350
351Sounds enourmously inefficient and complicated? Yes... please show me how
352to nuke perl's fd out of existence...
353
354=cut
355
356sub aio_close($;$) {
357 aio_block {
358 my ($fh, $cb) = @_;
359
360 my $pri = aioreq_pri;
361 my $grp = aio_group $cb;
362
363 my $fd = fileno $fh;
364
365 defined $fd or Carp::croak "aio_close called with fd-less filehandle";
366
367 # if the dups fail we will simply get EBADF
368 my $fd2 = _dup $fd;
369 aioreq_pri $pri;
370 add $grp _aio_close $fd2, sub {
371 my $fd2 = _dup $fd;
372 close $fh;
373 aioreq_pri $pri;
374 add $grp _aio_close $fd2, sub {
375 $grp->result ($_[0]);
376 };
377 };
378
379 $grp
380 }
381}
382
248 383
249=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 384=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250 385
251=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 386=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252 387
253Reads or writes C<length> bytes from the specified C<fh> and C<offset> 388Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254into the scalar given by C<data> and offset C<dataoffset> and calls the 389into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255callback without the actual number of bytes read (or -1 on error, just 390callback without the actual number of bytes read (or -1 on error, just
256like the syscall). 391like the syscall).
257 392
393If C<$offset> is undefined, then the current file descriptor offset will
394be used (and updated), otherwise the file descriptor offset will not be
395changed by these calls.
396
397If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
398
399If C<$dataoffset> is less than zero, it will be counted from the end of
400C<$data>.
401
258The C<$data> scalar I<MUST NOT> be modified in any way while the request 402The C<$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 403is outstanding. Modifying it can result in segfaults or World War III (if
260necessary/optional hardware is installed). 404the necessary/optional hardware is installed).
261 405
262Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 406Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263offset C<0> within the scalar: 407offset C<0> within the scalar:
264 408
265 aio_read $fh, 7, 15, $buffer, 0, sub { 409 aio_read $fh, 7, 15, $buffer, 0, sub {
266 $_[0] > 0 or die "read error: $!"; 410 $_[0] > 0 or die "read error: $!";
267 print "read $_[0] bytes: <$buffer>\n"; 411 print "read $_[0] bytes: <$buffer>\n";
268 }; 412 };
269 413
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}
344 414
345=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 415=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346 416
347Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 417Tries 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 418reading 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 432C<$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 433bytes 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 434provides 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 435value equals C<$length> one can assume that C<$length> bytes have been
366read. 436read.
437
367 438
368=item aio_readahead $fh,$offset,$length, $callback->($retval) 439=item aio_readahead $fh,$offset,$length, $callback->($retval)
369 440
370C<aio_readahead> populates the page cache with data from a file so that 441C<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> 442subsequent 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. 448file. The current file offset of the file is left unchanged.
378 449
379If that syscall doesn't exist (likely if your OS isn't Linux) it will be 450If 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. 451emulated by simply reading the data, which would have a similar effect.
381 452
453
382=item aio_stat $fh_or_path, $callback->($status) 454=item aio_stat $fh_or_path, $callback->($status)
383 455
384=item aio_lstat $fh, $callback->($status) 456=item aio_lstat $fh, $callback->($status)
385 457
386Works like perl's C<stat> or C<lstat> in void context. The callback will 458Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
399 aio_stat "/etc/passwd", sub { 471 aio_stat "/etc/passwd", sub {
400 $_[0] and die "stat failed: $!"; 472 $_[0] and die "stat failed: $!";
401 print "size is ", -s _, "\n"; 473 print "size is ", -s _, "\n";
402 }; 474 };
403 475
476
477=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
478
479Works like perl's C<utime> function (including the special case of $atime
480and $mtime being undef). Fractional times are supported if the underlying
481syscalls support them.
482
483When called with a pathname, uses utimes(2) if available, otherwise
484utime(2). If called on a file descriptor, uses futimes(2) if available,
485otherwise returns ENOSYS, so this is not portable.
486
487Examples:
488
489 # set atime and mtime to current time (basically touch(1)):
490 aio_utime "path", undef, undef;
491 # set atime to current time and mtime to beginning of the epoch:
492 aio_utime "path", time, undef; # undef==0
493
494
495=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
496
497Works like perl's C<chown> function, except that C<undef> for either $uid
498or $gid is being interpreted as "do not change" (but -1 can also be used).
499
500Examples:
501
502 # same as "chown root path" in the shell:
503 aio_chown "path", 0, -1;
504 # same as above:
505 aio_chown "path", 0, undef;
506
507
508=item aio_truncate $fh_or_path, $offset, $callback->($status)
509
510Works like truncate(2) or ftruncate(2).
511
512
513=item aio_chmod $fh_or_path, $mode, $callback->($status)
514
515Works like perl's C<chmod> function.
516
517
404=item aio_unlink $pathname, $callback->($status) 518=item aio_unlink $pathname, $callback->($status)
405 519
406Asynchronously unlink (delete) a file and call the callback with the 520Asynchronously unlink (delete) a file and call the callback with the
407result code. 521result code.
408 522
523
524=item aio_mknod $path, $mode, $dev, $callback->($status)
525
526[EXPERIMENTAL]
527
528Asynchronously create a device node (or fifo). See mknod(2).
529
530The only (POSIX-) portable way of calling this function is:
531
532 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
533
534
409=item aio_link $srcpath, $dstpath, $callback->($status) 535=item aio_link $srcpath, $dstpath, $callback->($status)
410 536
411Asynchronously create a new link to the existing object at C<$srcpath> at 537Asynchronously create a new link to the existing object at C<$srcpath> at
412the path C<$dstpath> and call the callback with the result code. 538the path C<$dstpath> and call the callback with the result code.
413 539
540
414=item aio_symlink $srcpath, $dstpath, $callback->($status) 541=item aio_symlink $srcpath, $dstpath, $callback->($status)
415 542
416Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 543Asynchronously 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. 544the path C<$dstpath> and call the callback with the result code.
418 545
546
547=item aio_readlink $path, $callback->($link)
548
549Asynchronously read the symlink specified by C<$path> and pass it to
550the callback. If an error occurs, nothing or undef gets passed to the
551callback.
552
553
419=item aio_rename $srcpath, $dstpath, $callback->($status) 554=item aio_rename $srcpath, $dstpath, $callback->($status)
420 555
421Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 556Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422rename(2) and call the callback with the result code. 557rename(2) and call the callback with the result code.
423 558
559
560=item aio_mkdir $pathname, $mode, $callback->($status)
561
562Asynchronously mkdir (create) a directory and call the callback with
563the result code. C<$mode> will be modified by the umask at the time the
564request is executed, so do not change your umask.
565
566
424=item aio_rmdir $pathname, $callback->($status) 567=item aio_rmdir $pathname, $callback->($status)
425 568
426Asynchronously rmdir (delete) a directory and call the callback with the 569Asynchronously rmdir (delete) a directory and call the callback with the
427result code. 570result code.
571
428 572
429=item aio_readdir $pathname, $callback->($entries) 573=item aio_readdir $pathname, $callback->($entries)
430 574
431Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 575Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432directory (i.e. opendir + readdir + closedir). The entries will not be 576directory (i.e. opendir + readdir + closedir). The entries will not be
433sorted, and will B<NOT> include the C<.> and C<..> entries. 577sorted, and will B<NOT> include the C<.> and C<..> entries.
434 578
435The callback a single argument which is either C<undef> or an array-ref 579The callback a single argument which is either C<undef> or an array-ref
436with the filenames. 580with the filenames.
581
582
583=item aio_load $path, $data, $callback->($status)
584
585This is a composite request that tries to fully load the given file into
586memory. Status is the same as with aio_read.
587
588=cut
589
590sub aio_load($$;$) {
591 aio_block {
592 my ($path, undef, $cb) = @_;
593 my $data = \$_[1];
594
595 my $pri = aioreq_pri;
596 my $grp = aio_group $cb;
597
598 aioreq_pri $pri;
599 add $grp aio_open $path, O_RDONLY, 0, sub {
600 my $fh = shift
601 or return $grp->result (-1);
602
603 aioreq_pri $pri;
604 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
605 $grp->result ($_[0]);
606 };
607 };
608
609 $grp
610 }
611}
612
613=item aio_copy $srcpath, $dstpath, $callback->($status)
614
615Try to copy the I<file> (directories not supported as either source or
616destination) from C<$srcpath> to C<$dstpath> and call the callback with
617the C<0> (error) or C<-1> ok.
618
619This is a composite request that it creates the destination file with
620mode 0200 and copies the contents of the source file into it using
621C<aio_sendfile>, followed by restoring atime, mtime, access mode and
622uid/gid, in that order.
623
624If an error occurs, the partial destination file will be unlinked, if
625possible, except when setting atime, mtime, access mode and uid/gid, where
626errors are being ignored.
627
628=cut
629
630sub aio_copy($$;$) {
631 aio_block {
632 my ($src, $dst, $cb) = @_;
633
634 my $pri = aioreq_pri;
635 my $grp = aio_group $cb;
636
637 aioreq_pri $pri;
638 add $grp aio_open $src, O_RDONLY, 0, sub {
639 if (my $src_fh = $_[0]) {
640 my @stat = stat $src_fh;
641
642 aioreq_pri $pri;
643 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
644 if (my $dst_fh = $_[0]) {
645 aioreq_pri $pri;
646 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
647 if ($_[0] == $stat[7]) {
648 $grp->result (0);
649 close $src_fh;
650
651 # those should not normally block. should. should.
652 utime $stat[8], $stat[9], $dst;
653 chmod $stat[2] & 07777, $dst_fh;
654 chown $stat[4], $stat[5], $dst_fh;
655 close $dst_fh;
656 } else {
657 $grp->result (-1);
658 close $src_fh;
659 close $dst_fh;
660
661 aioreq $pri;
662 add $grp aio_unlink $dst;
663 }
664 };
665 } else {
666 $grp->result (-1);
667 }
668 },
669
670 } else {
671 $grp->result (-1);
672 }
673 };
674
675 $grp
676 }
677}
678
679=item aio_move $srcpath, $dstpath, $callback->($status)
680
681Try to move the I<file> (directories not supported as either source or
682destination) from C<$srcpath> to C<$dstpath> and call the callback with
683the C<0> (error) or C<-1> ok.
684
685This is a composite request that tries to rename(2) the file first. If
686rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
687that is successful, unlinking the C<$srcpath>.
688
689=cut
690
691sub aio_move($$;$) {
692 aio_block {
693 my ($src, $dst, $cb) = @_;
694
695 my $pri = aioreq_pri;
696 my $grp = aio_group $cb;
697
698 aioreq_pri $pri;
699 add $grp aio_rename $src, $dst, sub {
700 if ($_[0] && $! == EXDEV) {
701 aioreq_pri $pri;
702 add $grp aio_copy $src, $dst, sub {
703 $grp->result ($_[0]);
704
705 if (!$_[0]) {
706 aioreq_pri $pri;
707 add $grp aio_unlink $src;
708 }
709 };
710 } else {
711 $grp->result ($_[0]);
712 }
713 };
714
715 $grp
716 }
717}
437 718
438=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 719=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439 720
440Scans a directory (similar to C<aio_readdir>) but additionally tries to 721Scans a directory (similar to C<aio_readdir>) but additionally tries to
441efficiently separate the entries of directory C<$path> into two sets of 722efficiently separate the entries of directory C<$path> into two sets of
… …
443recurse into (everything else, including symlinks to directories). 724recurse into (everything else, including symlinks to directories).
444 725
445C<aio_scandir> is a composite request that creates of many sub requests_ 726C<aio_scandir> is a composite request that creates of many sub requests_
446C<$maxreq> specifies the maximum number of outstanding aio requests that 727C<$maxreq> specifies the maximum number of outstanding aio requests that
447this function generates. If it is C<< <= 0 >>, then a suitable default 728this function generates. If it is C<< <= 0 >>, then a suitable default
448will be chosen (currently 6). 729will be chosen (currently 4).
449 730
450On error, the callback is called without arguments, otherwise it receives 731On error, the callback is called without arguments, otherwise it receives
451two array-refs with path-relative entry names. 732two array-refs with path-relative entry names.
452 733
453Example: 734Example:
… …
487as those tend to return 0 or 1 as link counts, which disables the 768as those tend to return 0 or 1 as link counts, which disables the
488directory counting heuristic. 769directory counting heuristic.
489 770
490=cut 771=cut
491 772
492sub aio_scandir($$$) { 773sub aio_scandir($$;$) {
774 aio_block {
493 my ($path, $maxreq, $cb) = @_; 775 my ($path, $maxreq, $cb) = @_;
494 776
495 my $pri = aioreq_pri; 777 my $pri = aioreq_pri;
496 778
497 my $grp = aio_group $cb; 779 my $grp = aio_group $cb;
498 780
499 $maxreq = 6 if $maxreq <= 0; 781 $maxreq = 4 if $maxreq <= 0;
500 782
501 # stat once 783 # 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; 784 aioreq_pri $pri;
510 add $grp aio_readdir $path, sub { 785 add $grp aio_stat $path, sub {
511 my $entries = shift
512 or return $grp->result (); 786 return $grp->result () if $_[0];
787 my $now = time;
788 my $hash1 = join ":", (stat _)[0,1,3,7,9];
513 789
514 # stat the dir another time 790 # read the directory entries
515 aioreq_pri $pri; 791 aioreq_pri $pri;
792 add $grp aio_readdir $path, sub {
793 my $entries = shift
794 or return $grp->result ();
795
796 # stat the dir another time
797 aioreq_pri $pri;
516 add $grp aio_stat $path, sub { 798 add $grp aio_stat $path, sub {
517 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 799 my $hash2 = join ":", (stat _)[0,1,3,7,9];
518 800
519 my $ndirs; 801 my $ndirs;
520 802
521 # take the slow route if anything looks fishy 803 # take the slow route if anything looks fishy
522 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 804 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523 $ndirs = -1; 805 $ndirs = -1;
524 } else { 806 } else {
525 # if nlink == 2, we are finished 807 # if nlink == 2, we are finished
526 # on non-posix-fs's, we rely on nlink < 2 808 # on non-posix-fs's, we rely on nlink < 2
527 $ndirs = (stat _)[3] - 2 809 $ndirs = (stat _)[3] - 2
528 or return $grp->result ([], $entries); 810 or return $grp->result ([], $entries);
529 } 811 }
530 812
531 # sort into likely dirs and likely nondirs 813 # sort into likely dirs and likely nondirs
532 # dirs == files without ".", short entries first 814 # dirs == files without ".", short entries first
533 $entries = [map $_->[0], 815 $entries = [map $_->[0],
534 sort { $b->[1] cmp $a->[1] } 816 sort { $b->[1] cmp $a->[1] }
535 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 817 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536 @$entries]; 818 @$entries];
537 819
538 my (@dirs, @nondirs); 820 my (@dirs, @nondirs);
539 821
540 my $statgrp = add $grp aio_group sub { 822 my $statgrp = add $grp aio_group sub {
541 $grp->result (\@dirs, \@nondirs); 823 $grp->result (\@dirs, \@nondirs);
542 }; 824 };
543 825
544 limit $statgrp $maxreq; 826 limit $statgrp $maxreq;
545 feed $statgrp sub { 827 feed $statgrp sub {
546 return unless @$entries; 828 return unless @$entries;
547 my $entry = pop @$entries; 829 my $entry = pop @$entries;
548 830
549 aioreq_pri $pri; 831 aioreq_pri $pri;
550 add $statgrp aio_stat "$path/$entry/.", sub { 832 add $statgrp aio_stat "$path/$entry/.", sub {
551 if ($_[0] < 0) { 833 if ($_[0] < 0) {
552 push @nondirs, $entry; 834 push @nondirs, $entry;
553 } else { 835 } else {
554 # need to check for real directory 836 # need to check for real directory
555 aioreq_pri $pri; 837 aioreq_pri $pri;
556 add $statgrp aio_lstat "$path/$entry", sub { 838 add $statgrp aio_lstat "$path/$entry", sub {
557 if (-d _) { 839 if (-d _) {
558 push @dirs, $entry; 840 push @dirs, $entry;
559 841
560 unless (--$ndirs) { 842 unless (--$ndirs) {
561 push @nondirs, @$entries; 843 push @nondirs, @$entries;
562 feed $statgrp; 844 feed $statgrp;
845 }
846 } else {
847 push @nondirs, $entry;
563 } 848 }
564 } else {
565 push @nondirs, $entry;
566 } 849 }
567 } 850 }
568 } 851 };
569 }; 852 };
570 }; 853 };
571 }; 854 };
572 }; 855 };
856
857 $grp
573 }; 858 }
574
575 $grp
576} 859}
860
861=item aio_rmtree $path, $callback->($status)
862
863Delete a directory tree starting (and including) C<$path>, return the
864status of the final C<rmdir> only. This is a composite request that
865uses C<aio_scandir> to recurse into and rmdir directories, and unlink
866everything else.
867
868=cut
869
870sub aio_rmtree;
871sub aio_rmtree($;$) {
872 aio_block {
873 my ($path, $cb) = @_;
874
875 my $pri = aioreq_pri;
876 my $grp = aio_group $cb;
877
878 aioreq_pri $pri;
879 add $grp aio_scandir $path, 0, sub {
880 my ($dirs, $nondirs) = @_;
881
882 my $dirgrp = aio_group sub {
883 add $grp aio_rmdir $path, sub {
884 $grp->result ($_[0]);
885 };
886 };
887
888 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
889 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
890
891 add $grp $dirgrp;
892 };
893
894 $grp
895 }
896}
897
898=item aio_sync $callback->($status)
899
900Asynchronously call sync and call the callback when finished.
577 901
578=item aio_fsync $fh, $callback->($status) 902=item aio_fsync $fh, $callback->($status)
579 903
580Asynchronously call fsync on the given filehandle and call the callback 904Asynchronously call fsync on the given filehandle and call the callback
581with the fsync result code. 905with the fsync result code.
… …
794 1118
795=back 1119=back
796 1120
797=head2 SUPPORT FUNCTIONS 1121=head2 SUPPORT FUNCTIONS
798 1122
1123=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1124
799=over 4 1125=over 4
800 1126
801=item $fileno = IO::AIO::poll_fileno 1127=item $fileno = IO::AIO::poll_fileno
802 1128
803Return the I<request result pipe file descriptor>. This filehandle must be 1129Return the I<request result pipe file descriptor>. This filehandle must be
… …
807 1133
808See C<poll_cb> for an example. 1134See C<poll_cb> for an example.
809 1135
810=item IO::AIO::poll_cb 1136=item IO::AIO::poll_cb
811 1137
812Process all outstanding events on the result pipe. You have to call this 1138Process some outstanding events on the result pipe. You have to call this
813regularly. Returns the number of events processed. Returns immediately 1139regularly. Returns the number of events processed. Returns immediately
814when no events are outstanding. 1140when no events are outstanding. The amount of events processed depends on
1141the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815 1142
816If not all requests were processed for whatever reason, the filehandle 1143If not all requests were processed for whatever reason, the filehandle
817will still be ready when C<poll_cb> returns. 1144will still be ready when C<poll_cb> returns.
818 1145
819Example: Install an Event watcher that automatically calls 1146Example: Install an Event watcher that automatically calls
… …
821 1148
822 Event->io (fd => IO::AIO::poll_fileno, 1149 Event->io (fd => IO::AIO::poll_fileno,
823 poll => 'r', async => 1, 1150 poll => 'r', async => 1,
824 cb => \&IO::AIO::poll_cb); 1151 cb => \&IO::AIO::poll_cb);
825 1152
826=item IO::AIO::poll_some $max_requests 1153=item IO::AIO::max_poll_reqs $nreqs
827 1154
828Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1155=item IO::AIO::max_poll_time $seconds
829at a time.
830 1156
831Useful if you want to ensure some level of interactiveness when perl is 1157These set the maximum number of requests (default C<0>, meaning infinity)
832not fast enough to process all requests in time. 1158that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1159the maximum amount of time (default C<0>, meaning infinity) spent in
1160C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1161of time C<poll_cb> is allowed to use).
1162
1163Setting C<max_poll_time> to a non-zero value creates an overhead of one
1164syscall per request processed, which is not normally a problem unless your
1165callbacks are really really fast or your OS is really really slow (I am
1166not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1167
1168Setting these is useful if you want to ensure some level of
1169interactiveness when perl is not fast enough to process all requests in
1170time.
1171
1172For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833 1173
834Example: Install an Event watcher that automatically calls 1174Example: Install an Event watcher that automatically calls
835IO::AIO::poll_some with low priority, to ensure that other parts of the 1175IO::AIO::poll_cb with low priority, to ensure that other parts of the
836program get the CPU sometimes even under high AIO load. 1176program get the CPU sometimes even under high AIO load.
837 1177
1178 # try not to spend much more than 0.1s in poll_cb
1179 IO::AIO::max_poll_time 0.1;
1180
1181 # use a low priority so other tasks have priority
838 Event->io (fd => IO::AIO::poll_fileno, 1182 Event->io (fd => IO::AIO::poll_fileno,
839 poll => 'r', nice => 1, 1183 poll => 'r', nice => 1,
840 cb => sub { IO::AIO::poll_some 256 }); 1184 cb => &IO::AIO::poll_cb);
841 1185
842=item IO::AIO::poll_wait 1186=item IO::AIO::poll_wait
843 1187
1188If there are any outstanding requests and none of them in the result
844Wait till the result filehandle becomes ready for reading (simply does a 1189phase, wait till the result filehandle becomes ready for reading (simply
845C<select> on the filehandle. This is useful if you want to synchronously wait 1190does a C<select> on the filehandle. This is useful if you want to
846for some requests to finish). 1191synchronously wait for some requests to finish).
847 1192
848See C<nreqs> for an example. 1193See C<nreqs> for an example.
849 1194
1195=item IO::AIO::poll
1196
1197Waits until some requests have been handled.
1198
1199Returns the number of requests processed, but is otherwise strictly
1200equivalent to:
1201
1202 IO::AIO::poll_wait, IO::AIO::poll_cb
1203
850=item IO::AIO::nreqs 1204=item IO::AIO::flush
851 1205
852Returns the number of requests currently in the ready, execute or pending 1206Wait till all outstanding AIO requests have been handled.
853states (i.e. for which their callback has not been invoked yet).
854 1207
855Example: wait till there are no outstanding requests anymore: 1208Strictly equivalent to:
856 1209
857 IO::AIO::poll_wait, IO::AIO::poll_cb 1210 IO::AIO::poll_wait, IO::AIO::poll_cb
858 while IO::AIO::nreqs; 1211 while IO::AIO::nreqs;
859 1212
860=item IO::AIO::nready 1213=back
861 1214
862Returns the number of requests currently in the ready state (not yet 1215=head3 CONTROLLING THE NUMBER OF THREADS
863executed).
864 1216
865=item IO::AIO::npending 1217=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 1218
888=item IO::AIO::min_parallel $nthreads 1219=item IO::AIO::min_parallel $nthreads
889 1220
890Set the minimum number of AIO threads to C<$nthreads>. The current 1221Set the minimum number of AIO threads to C<$nthreads>. The current
891default is C<8>, which means eight asynchronous operations can execute 1222default is C<8>, which means eight asynchronous operations can execute
892concurrently at any one time (the number of outstanding requests, 1223concurrently at any one time (the number of outstanding requests,
893however, is unlimited). 1224however, is unlimited).
894 1225
895IO::AIO starts threads only on demand, when an AIO request is queued and 1226IO::AIO starts threads only on demand, when an AIO request is queued and
896no free thread exists. 1227no free thread exists. Please note that queueing up a hundred requests can
1228create demand for a hundred threads, even if it turns out that everything
1229is in the cache and could have been processed faster by a single thread.
897 1230
898It is recommended to keep the number of threads relatively low, as some 1231It is recommended to keep the number of threads relatively low, as some
899Linux kernel versions will scale negatively with the number of threads 1232Linux kernel versions will scale negatively with the number of threads
900(higher parallelity => MUCH higher latency). With current Linux 2.6 1233(higher parallelity => MUCH higher latency). With current Linux 2.6
901versions, 4-32 threads should be fine. 1234versions, 4-32 threads should be fine.
… …
915This module automatically runs C<max_parallel 0> at program end, to ensure 1248This module automatically runs C<max_parallel 0> at program end, to ensure
916that all threads are killed and that there are no outstanding requests. 1249that all threads are killed and that there are no outstanding requests.
917 1250
918Under normal circumstances you don't need to call this function. 1251Under normal circumstances you don't need to call this function.
919 1252
1253=item IO::AIO::max_idle $nthreads
1254
1255Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1256threads that did not get a request to process within 10 seconds). That
1257means if a thread becomes idle while C<$nthreads> other threads are also
1258idle, it will free its resources and exit.
1259
1260This is useful when you allow a large number of threads (e.g. 100 or 1000)
1261to allow for extremely high load situations, but want to free resources
1262under normal circumstances (1000 threads can easily consume 30MB of RAM).
1263
1264The default is probably ok in most situations, especially if thread
1265creation is fast. If thread creation is very slow on your system you might
1266want to use larger values.
1267
920=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1268=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
921 1269
922This is a very bad function to use in interactive programs because it 1270This is a very bad function to use in interactive programs because it
923blocks, and a bad way to reduce concurrency because it is inexact: Better 1271blocks, and a bad way to reduce concurrency because it is inexact: Better
924use an C<aio_group> together with a feed callback. 1272use an C<aio_group> together with a feed callback.
925 1273
926Sets the maximum number of outstanding requests to C<$nreqs>. If you 1274Sets 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 1275do 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>) 1276C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
929function will block until the limit is no longer exceeded. 1277function will block until the limit is no longer exceeded.
930 1278
931The default value is very large, so there is no practical limit on the 1279The default value is very large, so there is no practical limit on the
932number of outstanding requests. 1280number of outstanding requests.
… …
935C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1283C<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). 1284as a stop gap to shield against fatal memory overflow (with large values).
937 1285
938=back 1286=back
939 1287
1288=head3 STATISTICAL INFORMATION
1289
1290=over
1291
1292=item IO::AIO::nreqs
1293
1294Returns the number of requests currently in the ready, execute or pending
1295states (i.e. for which their callback has not been invoked yet).
1296
1297Example: wait till there are no outstanding requests anymore:
1298
1299 IO::AIO::poll_wait, IO::AIO::poll_cb
1300 while IO::AIO::nreqs;
1301
1302=item IO::AIO::nready
1303
1304Returns the number of requests currently in the ready state (not yet
1305executed).
1306
1307=item IO::AIO::npending
1308
1309Returns the number of requests currently in the pending state (executed,
1310but not yet processed by poll_cb).
1311
1312=back
1313
940=cut 1314=cut
941 1315
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; 1316min_parallel 8;
959 1317
960END { 1318END { flush }
961 max_parallel 0;
962}
963 1319
9641; 13201;
965 1321
966=head2 FORK BEHAVIOUR 1322=head2 FORK BEHAVIOUR
967 1323
… …
987bytes of memory. In addition, stat requests need a stat buffer (possibly 1343bytes of memory. In addition, stat requests need a stat buffer (possibly
988a few hundred bytes), readdir requires a result buffer and so on. Perl 1344a few hundred bytes), readdir requires a result buffer and so on. Perl
989scalars and other data passed into aio requests will also be locked and 1345scalars and other data passed into aio requests will also be locked and
990will consume memory till the request has entered the done state. 1346will consume memory till the request has entered the done state.
991 1347
992This is now awfully much, so queuing lots of requests is not usually a 1348This is not awfully much, so queuing lots of requests is not usually a
993problem. 1349problem.
994 1350
995Per-thread usage: 1351Per-thread usage:
996 1352
997In the execution phase, some aio requests require more memory for 1353In the execution phase, some aio requests require more memory for

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