… | |
… | |
18 | }; |
18 | }; |
19 | |
19 | |
20 | # version 2+ has request and group objects |
20 | # version 2+ has request and group objects |
21 | use IO::AIO 2; |
21 | use IO::AIO 2; |
22 | |
22 | |
|
|
23 | aioreq_pri 4; # give next request a very high priority |
23 | my $req = aio_unlink "/tmp/file", sub { }; |
24 | my $req = aio_unlink "/tmp/file", sub { }; |
24 | $req->cancel; # cancel request if still in queue |
25 | $req->cancel; # cancel request if still in queue |
25 | |
26 | |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
27 | my $grp = aio_group sub { print "all stats done\n" }; |
27 | add $grp aio_stat "..." for ...; |
28 | add $grp aio_stat "..." for ...; |
… | |
… | |
50 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
51 | |
52 | |
52 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
53 | operating system supports. |
54 | operating system supports. |
54 | |
55 | |
55 | Currently, a number of threads are started that execute your read/writes |
56 | In this version, a number of threads are started that execute your |
56 | and signal their completion. You don't need thread support in your libc or |
57 | requests and signal their completion. You don't need thread support |
57 | perl, and the threads created by this module will not be visible to the |
58 | in perl, and the threads created by this module will not be visible |
58 | pthreads library. In the future, this module might make use of the native |
59 | to perl. In the future, this module might make use of the native aio |
59 | aio functions available on many operating systems. However, they are often |
60 | functions available on many operating systems. However, they are often |
60 | not well-supported (Linux doesn't allow them on normal files currently, |
61 | not well-supported or restricted (Linux doesn't allow them on normal |
61 | for example), and they would only support aio_read and aio_write, so the |
62 | files currently, for example), and they would only support aio_read and |
62 | remaining functionality would have to be implemented using threads anyway. |
63 | aio_write, so the remaining functionality would have to be implemented |
|
|
64 | using threads anyway. |
63 | |
65 | |
64 | Although the module will work with in the presence of other threads, it is |
66 | Although the module will work with in the presence of other (Perl-) |
65 | currently not reentrant, so use appropriate locking yourself, always call |
67 | threads, it is currently not reentrant in any way, so use appropriate |
66 | C<poll_cb> from within the same thread, or never call C<poll_cb> (or other |
68 | locking yourself, always call C<poll_cb> from within the same thread, or |
67 | C<aio_> functions) recursively. |
69 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
|
|
70 | |
|
|
71 | =head1 REQUEST ANATOMY AND LIFETIME |
|
|
72 | |
|
|
73 | Every C<aio_*> function creates a request. which is a C data structure not |
|
|
74 | directly visible to Perl. |
|
|
75 | |
|
|
76 | If called in non-void context, every request function returns a Perl |
|
|
77 | object representing the request. In void context, nothing is returned, |
|
|
78 | which saves a bit of memory. |
|
|
79 | |
|
|
80 | The perl object is a fairly standard ref-to-hash object. The hash contents |
|
|
81 | are not used by IO::AIO so you are free to store anything you like in it. |
|
|
82 | |
|
|
83 | During their existance, aio requests travel through the following states, |
|
|
84 | in order: |
|
|
85 | |
|
|
86 | =over 4 |
|
|
87 | |
|
|
88 | =item ready |
|
|
89 | |
|
|
90 | Immediately after a request is created it is put into the ready state, |
|
|
91 | waiting for a thread to execute it. |
|
|
92 | |
|
|
93 | =item execute |
|
|
94 | |
|
|
95 | A thread has accepted the request for processing and is currently |
|
|
96 | executing it (e.g. blocking in read). |
|
|
97 | |
|
|
98 | =item pending |
|
|
99 | |
|
|
100 | The request has been executed and is waiting for result processing. |
|
|
101 | |
|
|
102 | While request submission and execution is fully asynchronous, result |
|
|
103 | processing is not and relies on the perl interpreter calling C<poll_cb> |
|
|
104 | (or another function with the same effect). |
|
|
105 | |
|
|
106 | =item result |
|
|
107 | |
|
|
108 | The request results are processed synchronously by C<poll_cb>. |
|
|
109 | |
|
|
110 | The C<poll_cb> function will process all outstanding aio requests by |
|
|
111 | calling their callbacks, freeing memory associated with them and managing |
|
|
112 | any groups they are contained in. |
|
|
113 | |
|
|
114 | =item done |
|
|
115 | |
|
|
116 | Request 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 |
|
|
118 | aio request is severed and calling its methods will either do nothing or |
|
|
119 | result in a runtime error). |
68 | |
120 | |
69 | =cut |
121 | =cut |
70 | |
122 | |
71 | package IO::AIO; |
123 | package IO::AIO; |
72 | |
124 | |
… | |
… | |
76 | use base 'Exporter'; |
128 | use base 'Exporter'; |
77 | |
129 | |
78 | BEGIN { |
130 | BEGIN { |
79 | our $VERSION = '2.0'; |
131 | our $VERSION = '2.0'; |
80 | |
132 | |
81 | our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
133 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
82 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
134 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
83 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
135 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
84 | aio_group aio_nop); |
136 | aio_group aio_nop); |
85 | our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
137 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
|
|
138 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
|
|
139 | min_parallel max_parallel nreqs nready npending); |
86 | |
140 | |
87 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
141 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
88 | |
142 | |
89 | require XSLoader; |
143 | require XSLoader; |
90 | XSLoader::load ("IO::AIO", $VERSION); |
144 | XSLoader::load ("IO::AIO", $VERSION); |
… | |
… | |
120 | your pathnames to the locale (or other) encoding in effect in the user |
174 | your pathnames to the locale (or other) encoding in effect in the user |
121 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
175 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
122 | use something else. |
176 | use something else. |
123 | |
177 | |
124 | =over 4 |
178 | =over 4 |
|
|
179 | |
|
|
180 | =item $prev_pri = aioreq_pri [$pri] |
|
|
181 | |
|
|
182 | Returns the priority value that would be used for the next request and, if |
|
|
183 | C<$pri> is given, sets the priority for the next aio request. |
|
|
184 | |
|
|
185 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
|
|
186 | and C<4>, respectively. Requests with higher priority will be serviced |
|
|
187 | first. |
|
|
188 | |
|
|
189 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
|
|
190 | functions. |
|
|
191 | |
|
|
192 | Example: open a file with low priority, then read something from it with |
|
|
193 | higher priority so the read request is serviced before other low priority |
|
|
194 | open requests (potentially spamming the cache): |
|
|
195 | |
|
|
196 | aioreq_pri -3; |
|
|
197 | aio_open ..., sub { |
|
|
198 | return unless $_[0]; |
|
|
199 | |
|
|
200 | aioreq_pri -2; |
|
|
201 | aio_read $_[0], ..., sub { |
|
|
202 | ... |
|
|
203 | }; |
|
|
204 | }; |
|
|
205 | |
|
|
206 | =item aioreq_nice $pri_adjust |
|
|
207 | |
|
|
208 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
|
209 | priority, so effects are cumulative. |
125 | |
210 | |
126 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
211 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
127 | |
212 | |
128 | Asynchronously open or create a file and call the callback with a newly |
213 | Asynchronously open or create a file and call the callback with a newly |
129 | created filehandle for the file. |
214 | created filehandle for the file. |
… | |
… | |
182 | print "read $_[0] bytes: <$buffer>\n"; |
267 | print "read $_[0] bytes: <$buffer>\n"; |
183 | }; |
268 | }; |
184 | |
269 | |
185 | =item aio_move $srcpath, $dstpath, $callback->($status) |
270 | =item aio_move $srcpath, $dstpath, $callback->($status) |
186 | |
271 | |
187 | [EXPERIMENTAL due to internal aio_group use] |
|
|
188 | |
|
|
189 | Try to move the I<file> (directories not supported as either source or |
272 | Try to move the I<file> (directories not supported as either source or |
190 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
273 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
191 | the C<0> (error) or C<-1> ok. |
274 | the C<0> (error) or C<-1> ok. |
192 | |
275 | |
193 | This is a composite request that tries to rename(2) the file first. If |
276 | This is a composite request that tries to rename(2) the file first. If |
… | |
… | |
203 | =cut |
286 | =cut |
204 | |
287 | |
205 | sub aio_move($$$) { |
288 | sub aio_move($$$) { |
206 | my ($src, $dst, $cb) = @_; |
289 | my ($src, $dst, $cb) = @_; |
207 | |
290 | |
|
|
291 | my $pri = aioreq_pri; |
208 | my $grp = aio_group $cb; |
292 | my $grp = aio_group $cb; |
209 | |
293 | |
|
|
294 | aioreq_pri $pri; |
210 | add $grp aio_rename $src, $dst, sub { |
295 | add $grp aio_rename $src, $dst, sub { |
211 | if ($_[0] && $! == EXDEV) { |
296 | if ($_[0] && $! == EXDEV) { |
|
|
297 | aioreq_pri $pri; |
212 | add $grp aio_open $src, O_RDONLY, 0, sub { |
298 | add $grp aio_open $src, O_RDONLY, 0, sub { |
213 | if (my $src_fh = $_[0]) { |
299 | if (my $src_fh = $_[0]) { |
214 | my @stat = stat $src_fh; |
300 | my @stat = stat $src_fh; |
215 | |
301 | |
|
|
302 | aioreq_pri $pri; |
216 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
303 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
217 | if (my $dst_fh = $_[0]) { |
304 | if (my $dst_fh = $_[0]) { |
|
|
305 | aioreq_pri $pri; |
218 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
306 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
219 | close $src_fh; |
307 | close $src_fh; |
220 | |
308 | |
221 | if ($_[0] == $stat[7]) { |
309 | if ($_[0] == $stat[7]) { |
222 | utime $stat[8], $stat[9], $dst; |
310 | utime $stat[8], $stat[9], $dst; |
223 | chmod $stat[2] & 07777, $dst_fh; |
311 | chmod $stat[2] & 07777, $dst_fh; |
224 | chown $stat[4], $stat[5], $dst_fh; |
312 | chown $stat[4], $stat[5], $dst_fh; |
225 | close $dst_fh; |
313 | close $dst_fh; |
226 | |
314 | |
|
|
315 | aioreq_pri $pri; |
227 | add $grp aio_unlink $src, sub { |
316 | add $grp aio_unlink $src, sub { |
228 | $grp->result ($_[0]); |
317 | $grp->result ($_[0]); |
229 | }; |
318 | }; |
230 | } else { |
319 | } else { |
231 | my $errno = $!; |
320 | my $errno = $!; |
|
|
321 | aioreq_pri $pri; |
232 | add $grp aio_unlink $dst, sub { |
322 | add $grp aio_unlink $dst, sub { |
233 | $! = $errno; |
323 | $! = $errno; |
234 | $grp->result (-1); |
324 | $grp->result (-1); |
235 | }; |
325 | }; |
236 | } |
326 | } |
… | |
… | |
345 | The callback a single argument which is either C<undef> or an array-ref |
435 | The callback a single argument which is either C<undef> or an array-ref |
346 | with the filenames. |
436 | with the filenames. |
347 | |
437 | |
348 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
438 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
349 | |
439 | |
350 | [EXPERIMENTAL due to internal aio_group use] |
|
|
351 | |
|
|
352 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
440 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
353 | separate the entries of directory C<$path> into two sets of names, ones |
441 | efficiently separate the entries of directory C<$path> into two sets of |
354 | you can recurse into (directories or links to them), and ones you cannot |
442 | names, directories you can recurse into (directories), and ones you cannot |
355 | recurse into (everything else). |
443 | recurse into (everything else, including symlinks to directories). |
356 | |
444 | |
357 | C<aio_scandir> is a composite request that creates of many sub requests_ |
445 | C<aio_scandir> is a composite request that creates of many sub requests_ |
358 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
446 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
359 | this function generates. If it is C<< <= 0 >>, then a suitable default |
447 | this function generates. If it is C<< <= 0 >>, then a suitable default |
360 | will be chosen (currently 6). |
448 | will be chosen (currently 6). |
… | |
… | |
402 | =cut |
490 | =cut |
403 | |
491 | |
404 | sub aio_scandir($$$) { |
492 | sub aio_scandir($$$) { |
405 | my ($path, $maxreq, $cb) = @_; |
493 | my ($path, $maxreq, $cb) = @_; |
406 | |
494 | |
|
|
495 | my $pri = aioreq_pri; |
|
|
496 | |
407 | my $grp = aio_group $cb; |
497 | my $grp = aio_group $cb; |
408 | |
498 | |
409 | $maxreq = 6 if $maxreq <= 0; |
499 | $maxreq = 6 if $maxreq <= 0; |
410 | |
500 | |
411 | # stat once |
501 | # stat once |
|
|
502 | aioreq_pri $pri; |
412 | add $grp aio_stat $path, sub { |
503 | add $grp aio_stat $path, sub { |
413 | return $grp->result () if $_[0]; |
504 | return $grp->result () if $_[0]; |
414 | my $now = time; |
505 | my $now = time; |
415 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
506 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
416 | |
507 | |
417 | # read the directory entries |
508 | # read the directory entries |
|
|
509 | aioreq_pri $pri; |
418 | add $grp aio_readdir $path, sub { |
510 | add $grp aio_readdir $path, sub { |
419 | my $entries = shift |
511 | my $entries = shift |
420 | or return $grp->result (); |
512 | or return $grp->result (); |
421 | |
513 | |
422 | # stat the dir another time |
514 | # stat the dir another time |
|
|
515 | aioreq_pri $pri; |
423 | add $grp aio_stat $path, sub { |
516 | add $grp aio_stat $path, sub { |
424 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
517 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
425 | |
518 | |
426 | my $ndirs; |
519 | my $ndirs; |
427 | |
520 | |
… | |
… | |
442 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
535 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
443 | @$entries]; |
536 | @$entries]; |
444 | |
537 | |
445 | my (@dirs, @nondirs); |
538 | my (@dirs, @nondirs); |
446 | |
539 | |
447 | my ($statcb, $schedcb); |
|
|
448 | my $nreq = 0; |
|
|
449 | |
|
|
450 | my $statgrp = add $grp aio_group; |
540 | my $statgrp = add $grp aio_group sub { |
|
|
541 | $grp->result (\@dirs, \@nondirs); |
|
|
542 | }; |
451 | |
543 | |
452 | $schedcb = sub { |
544 | limit $statgrp $maxreq; |
453 | if (@$entries) { |
545 | feed $statgrp sub { |
454 | if ($nreq < $maxreq) { |
546 | return unless @$entries; |
455 | my $ent = pop @$entries; |
547 | my $entry = pop @$entries; |
|
|
548 | |
|
|
549 | aioreq_pri $pri; |
|
|
550 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
551 | if ($_[0] < 0) { |
|
|
552 | push @nondirs, $entry; |
|
|
553 | } else { |
|
|
554 | # need to check for real directory |
|
|
555 | aioreq_pri $pri; |
|
|
556 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
557 | if (-d _) { |
|
|
558 | push @dirs, $entry; |
|
|
559 | |
|
|
560 | unless (--$ndirs) { |
|
|
561 | push @nondirs, @$entries; |
|
|
562 | feed $statgrp; |
|
|
563 | } |
|
|
564 | } else { |
|
|
565 | push @nondirs, $entry; |
|
|
566 | } |
456 | $nreq++; |
567 | } |
457 | add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
|
|
458 | } |
568 | } |
459 | } elsif (!$nreq) { |
|
|
460 | # finished |
|
|
461 | $statgrp->cancel; |
|
|
462 | undef $statcb; |
|
|
463 | undef $schedcb; |
|
|
464 | $grp->result (\@dirs, \@nondirs); |
|
|
465 | } |
569 | }; |
466 | }; |
570 | }; |
467 | $statcb = sub { |
|
|
468 | my ($status, $entry) = @_; |
|
|
469 | |
|
|
470 | if ($status < 0) { |
|
|
471 | $nreq--; |
|
|
472 | push @nondirs, $entry; |
|
|
473 | &$schedcb; |
|
|
474 | } else { |
|
|
475 | # need to check for real directory |
|
|
476 | add $grp aio_lstat "$path/$entry", sub { |
|
|
477 | $nreq--; |
|
|
478 | |
|
|
479 | if (-d _) { |
|
|
480 | push @dirs, $entry; |
|
|
481 | |
|
|
482 | if (!--$ndirs) { |
|
|
483 | push @nondirs, @$entries; |
|
|
484 | $entries = []; |
|
|
485 | } |
|
|
486 | } else { |
|
|
487 | push @nondirs, $entry; |
|
|
488 | } |
|
|
489 | |
|
|
490 | &$schedcb; |
|
|
491 | } |
|
|
492 | } |
|
|
493 | }; |
|
|
494 | |
|
|
495 | &$schedcb while @$entries && $nreq < $maxreq; |
|
|
496 | }; |
571 | }; |
497 | }; |
572 | }; |
498 | }; |
573 | }; |
499 | |
574 | |
500 | $grp |
575 | $grp |
… | |
… | |
513 | If this call isn't available because your OS lacks it or it couldn't be |
588 | If this call isn't available because your OS lacks it or it couldn't be |
514 | detected, it will be emulated by calling C<fsync> instead. |
589 | detected, it will be emulated by calling C<fsync> instead. |
515 | |
590 | |
516 | =item aio_group $callback->(...) |
591 | =item aio_group $callback->(...) |
517 | |
592 | |
518 | [EXPERIMENTAL] |
|
|
519 | |
|
|
520 | This is a very special aio request: Instead of doing something, it is a |
593 | This is a very special aio request: Instead of doing something, it is a |
521 | container for other aio requests, which is useful if you want to bundle |
594 | container for other aio requests, which is useful if you want to bundle |
522 | many requests into a single, composite, request. |
595 | many requests into a single, composite, request with a definite callback |
|
|
596 | and the ability to cancel the whole request with its subrequests. |
523 | |
597 | |
524 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
598 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
525 | for more info. |
599 | for more info. |
526 | |
600 | |
527 | Example: |
601 | Example: |
… | |
… | |
540 | This is a special request - it does nothing in itself and is only used for |
614 | This is a special request - it does nothing in itself and is only used for |
541 | side effects, such as when you want to add a dummy request to a group so |
615 | side effects, such as when you want to add a dummy request to a group so |
542 | that finishing the requests in the group depends on executing the given |
616 | that finishing the requests in the group depends on executing the given |
543 | code. |
617 | code. |
544 | |
618 | |
|
|
619 | While this request does nothing, it still goes through the execution |
|
|
620 | phase and still requires a worker thread. Thus, the callback will not |
|
|
621 | be executed immediately but only after other requests in the queue have |
|
|
622 | entered their execution phase. This can be used to measure request |
|
|
623 | latency. |
|
|
624 | |
545 | =item IO::AIO::aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
625 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
546 | |
626 | |
547 | Mainly used for debugging and benchmarking, this aio request puts one of |
627 | Mainly used for debugging and benchmarking, this aio request puts one of |
548 | the request workers to sleep for the given time. |
628 | the request workers to sleep for the given time. |
549 | |
629 | |
550 | While it is theoretically handy to have simple I/O scheduling requests |
630 | While it is theoretically handy to have simple I/O scheduling requests |
551 | like sleep and file handle readable/writable, the overhead this creates |
631 | like sleep and file handle readable/writable, the overhead this creates is |
552 | is immense, so do not use this function except to put your application |
632 | immense (it blocks a thread for a long time) so do not use this function |
553 | under artificial I/O pressure. |
633 | except to put your application under artificial I/O pressure. |
554 | |
634 | |
555 | =back |
635 | =back |
556 | |
636 | |
557 | =head2 IO::AIO::REQ CLASS |
637 | =head2 IO::AIO::REQ CLASS |
558 | |
638 | |
559 | All non-aggregate C<aio_*> functions return an object of this class when |
639 | All non-aggregate C<aio_*> functions return an object of this class when |
560 | called in non-void context. |
640 | called in non-void context. |
561 | |
641 | |
562 | A request always moves through the following five states in its lifetime, |
|
|
563 | in order: B<ready> (request has been created, but has not been executed |
|
|
564 | yet), B<execute> (request is currently being executed), B<pending> |
|
|
565 | (request has been executed but callback has not been called yet), |
|
|
566 | B<result> (results are being processed synchronously, includes calling the |
|
|
567 | callback) and B<done> (request has reached the end of its lifetime and |
|
|
568 | holds no resources anymore). |
|
|
569 | |
|
|
570 | =over 4 |
642 | =over 4 |
571 | |
643 | |
572 | =item $req->cancel |
644 | =item cancel $req |
573 | |
645 | |
574 | Cancels the request, if possible. Has the effect of skipping execution |
646 | Cancels the request, if possible. Has the effect of skipping execution |
575 | when entering the B<execute> state and skipping calling the callback when |
647 | when entering the B<execute> state and skipping calling the callback when |
576 | entering the the B<result> state, but will leave the request otherwise |
648 | entering the the B<result> state, but will leave the request otherwise |
577 | untouched. That means that requests that currently execute will not be |
649 | untouched. That means that requests that currently execute will not be |
578 | stopped and resources held by the request will not be freed prematurely. |
650 | stopped and resources held by the request will not be freed prematurely. |
579 | |
651 | |
|
|
652 | =item cb $req $callback->(...) |
|
|
653 | |
|
|
654 | Replace (or simply set) the callback registered to the request. |
|
|
655 | |
580 | =back |
656 | =back |
581 | |
657 | |
582 | =head2 IO::AIO::GRP CLASS |
658 | =head2 IO::AIO::GRP CLASS |
583 | |
659 | |
584 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
660 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
… | |
… | |
623 | =item * They can also can also be added to other IO::AIO::GRP objects. |
699 | =item * They can also can also be added to other IO::AIO::GRP objects. |
624 | |
700 | |
625 | =item * You must not add requests to a group from within the group callback (or |
701 | =item * You must not add requests to a group from within the group callback (or |
626 | any later time). |
702 | any later time). |
627 | |
703 | |
628 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
629 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
630 | this kind of concurrency-limiting. |
|
|
631 | |
|
|
632 | =back |
704 | =back |
633 | |
705 | |
634 | Their lifetime, simplified, looks like this: when they are empty, they |
706 | Their lifetime, simplified, looks like this: when they are empty, they |
635 | will finish very quickly. If they contain only requests that are in the |
707 | will finish very quickly. If they contain only requests that are in the |
636 | C<done> state, they will also finish. Otherwise they will continue to |
708 | C<done> state, they will also finish. Otherwise they will continue to |
… | |
… | |
641 | group. And only when all those requests have finished will the the group |
713 | group. And only when all those requests have finished will the the group |
642 | itself finish. |
714 | itself finish. |
643 | |
715 | |
644 | =over 4 |
716 | =over 4 |
645 | |
717 | |
|
|
718 | =item add $grp ... |
|
|
719 | |
646 | =item $grp->add (...) |
720 | =item $grp->add (...) |
647 | |
|
|
648 | =item add $grp ... |
|
|
649 | |
721 | |
650 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
722 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
651 | be added, including other groups, as long as you do not create circular |
723 | be added, including other groups, as long as you do not create circular |
652 | dependencies. |
724 | dependencies. |
653 | |
725 | |
654 | Returns all its arguments. |
726 | Returns all its arguments. |
655 | |
727 | |
|
|
728 | =item $grp->cancel_subs |
|
|
729 | |
|
|
730 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
731 | itself. Useful when you queued a lot of events but got a result early. |
|
|
732 | |
656 | =item $grp->result (...) |
733 | =item $grp->result (...) |
657 | |
734 | |
658 | Set the result value(s) that will be passed to the group callback when all |
735 | Set the result value(s) that will be passed to the group callback when all |
659 | subrequests have finished. By default, no argument will be passed. |
736 | subrequests have finished and set thre groups errno to the current value |
|
|
737 | of errno (just like calling C<errno> without an error number). By default, |
|
|
738 | no argument will be passed and errno is zero. |
660 | |
739 | |
661 | =item $grp->set_feeder ($callback->($grp)) |
740 | =item $grp->errno ([$errno]) |
662 | |
741 | |
663 | [VERY EXPERIMENTAL] |
742 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
743 | when the argument is missing. |
|
|
744 | |
|
|
745 | Every aio request has an associated errno value that is restored when |
|
|
746 | the callback is invoked. This method lets you change this value from its |
|
|
747 | default (0). |
|
|
748 | |
|
|
749 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
750 | before the call to C<result>, or call c<errno> after it. |
|
|
751 | |
|
|
752 | =item feed $grp $callback->($grp) |
664 | |
753 | |
665 | Sets a feeder/generator on this group: every group can have an attached |
754 | Sets a feeder/generator on this group: every group can have an attached |
666 | generator that generates requests if idle. The idea behind this is that, |
755 | generator that generates requests if idle. The idea behind this is that, |
667 | although you could just queue as many requests as you want in a group, |
756 | although you could just queue as many requests as you want in a group, |
668 | this might starve other requests for a potentially long time. For |
757 | this might starve other requests for a potentially long time. For |
669 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
758 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
670 | requests, delaying any later requests for a long time. |
759 | requests, delaying any later requests for a long time. |
671 | |
760 | |
672 | To avoid this, and allow incremental generation of requests, you can |
761 | To avoid this, and allow incremental generation of requests, you can |
673 | instead a group and set a feeder on it that generates those requests. The |
762 | instead a group and set a feeder on it that generates those requests. The |
674 | feeder will be called whenever there are few enough (see C<feeder_limit>, |
763 | feed callback will be called whenever there are few enough (see C<limit>, |
675 | below) requests active in the group itself and is expected to queue more |
764 | below) requests active in the group itself and is expected to queue more |
676 | requests. |
765 | requests. |
677 | |
766 | |
678 | The feeder can queue as many requests as it likes (i.e. C<add> does not |
767 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
679 | impose any limits). |
768 | not impose any limits). |
680 | |
769 | |
681 | If the feeder does not queue more requests when called, it will be |
770 | If the feed does not queue more requests when called, it will be |
682 | automatically removed from the group. |
771 | automatically removed from the group. |
683 | |
772 | |
684 | If the feeder limit is C<0>, it will be set to C<2> automatically. |
773 | If the feed limit is C<0>, it will be set to C<2> automatically. |
685 | |
774 | |
686 | Example: |
775 | Example: |
687 | |
776 | |
688 | # stat all files in @files, but only ever use four aio requests concurrently: |
777 | # stat all files in @files, but only ever use four aio requests concurrently: |
689 | |
778 | |
690 | my $grp = aio_group sub { print "finished\n" }; |
779 | my $grp = aio_group sub { print "finished\n" }; |
691 | $grp->feeder_limit (4); |
780 | limit $grp 4; |
692 | $grp->set_feeder (sub { |
781 | feed $grp sub { |
693 | my $file = pop @files |
782 | my $file = pop @files |
694 | or return; |
783 | or return; |
695 | |
784 | |
696 | add $grp aio_stat $file, sub { ... }; |
785 | add $grp aio_stat $file, sub { ... }; |
697 | }); |
786 | }; |
698 | |
787 | |
699 | =item $grp->feeder_limit ($num) |
788 | =item limit $grp $num |
700 | |
789 | |
701 | Sets the feeder limit for the group: The feeder will be called whenever |
790 | Sets the feeder limit for the group: The feeder will be called whenever |
702 | the group contains less than this many requests. |
791 | the group contains less than this many requests. |
703 | |
792 | |
704 | Setting the limit to C<0> will pause the feeding process. |
793 | Setting the limit to C<0> will pause the feeding process. |
… | |
… | |
722 | |
811 | |
723 | Process all outstanding events on the result pipe. You have to call this |
812 | Process all outstanding events on the result pipe. You have to call this |
724 | regularly. Returns the number of events processed. Returns immediately |
813 | regularly. Returns the number of events processed. Returns immediately |
725 | when no events are outstanding. |
814 | when no events are outstanding. |
726 | |
815 | |
|
|
816 | If not all requests were processed for whatever reason, the filehandle |
|
|
817 | will still be ready when C<poll_cb> returns. |
|
|
818 | |
727 | Example: Install an Event watcher that automatically calls |
819 | Example: Install an Event watcher that automatically calls |
728 | IO::AIO::poll_cb with high priority: |
820 | IO::AIO::poll_cb with high priority: |
729 | |
821 | |
730 | Event->io (fd => IO::AIO::poll_fileno, |
822 | Event->io (fd => IO::AIO::poll_fileno, |
731 | poll => 'r', async => 1, |
823 | poll => 'r', async => 1, |
732 | cb => \&IO::AIO::poll_cb); |
824 | cb => \&IO::AIO::poll_cb); |
733 | |
825 | |
|
|
826 | =item IO::AIO::poll_some $max_requests |
|
|
827 | |
|
|
828 | Similar to C<poll_cb>, but only processes up to C<$max_requests> requests |
|
|
829 | at a time. |
|
|
830 | |
|
|
831 | Useful if you want to ensure some level of interactiveness when perl is |
|
|
832 | not fast enough to process all requests in time. |
|
|
833 | |
|
|
834 | Example: Install an Event watcher that automatically calls |
|
|
835 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
|
|
836 | program get the CPU sometimes even under high AIO load. |
|
|
837 | |
|
|
838 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
839 | poll => 'r', nice => 1, |
|
|
840 | cb => sub { IO::AIO::poll_some 256 }); |
|
|
841 | |
734 | =item IO::AIO::poll_wait |
842 | =item IO::AIO::poll_wait |
735 | |
843 | |
736 | Wait till the result filehandle becomes ready for reading (simply does a |
844 | Wait till the result filehandle becomes ready for reading (simply does a |
737 | C<select> on the filehandle. This is useful if you want to synchronously wait |
845 | C<select> on the filehandle. This is useful if you want to synchronously wait |
738 | for some requests to finish). |
846 | for some requests to finish). |
739 | |
847 | |
740 | See C<nreqs> for an example. |
848 | See C<nreqs> for an example. |
741 | |
849 | |
742 | =item IO::AIO::nreqs |
850 | =item IO::AIO::nreqs |
743 | |
851 | |
744 | Returns the number of requests currently outstanding (i.e. for which their |
852 | Returns the number of requests currently in the ready, execute or pending |
745 | callback has not been invoked yet). |
853 | states (i.e. for which their callback has not been invoked yet). |
746 | |
854 | |
747 | Example: wait till there are no outstanding requests anymore: |
855 | Example: wait till there are no outstanding requests anymore: |
748 | |
856 | |
749 | IO::AIO::poll_wait, IO::AIO::poll_cb |
857 | IO::AIO::poll_wait, IO::AIO::poll_cb |
750 | while IO::AIO::nreqs; |
858 | while IO::AIO::nreqs; |
|
|
859 | |
|
|
860 | =item IO::AIO::nready |
|
|
861 | |
|
|
862 | Returns the number of requests currently in the ready state (not yet |
|
|
863 | executed). |
|
|
864 | |
|
|
865 | =item IO::AIO::npending |
|
|
866 | |
|
|
867 | Returns the number of requests currently in the pending state (executed, |
|
|
868 | but not yet processed by poll_cb). |
751 | |
869 | |
752 | =item IO::AIO::flush |
870 | =item IO::AIO::flush |
753 | |
871 | |
754 | Wait till all outstanding AIO requests have been handled. |
872 | Wait till all outstanding AIO requests have been handled. |
755 | |
873 | |
… | |
… | |
797 | This module automatically runs C<max_parallel 0> at program end, to ensure |
915 | This module automatically runs C<max_parallel 0> at program end, to ensure |
798 | that all threads are killed and that there are no outstanding requests. |
916 | that all threads are killed and that there are no outstanding requests. |
799 | |
917 | |
800 | Under normal circumstances you don't need to call this function. |
918 | Under normal circumstances you don't need to call this function. |
801 | |
919 | |
802 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
920 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
803 | |
921 | |
804 | [DEPRECATED] |
922 | This is a very bad function to use in interactive programs because it |
|
|
923 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
924 | use an C<aio_group> together with a feed callback. |
805 | |
925 | |
806 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
926 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
807 | try to queue up more than this number of requests, the caller will block until |
927 | to queue up more than this number of requests, the next call to the |
808 | some requests have been handled. |
928 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
929 | function will block until the limit is no longer exceeded. |
809 | |
930 | |
810 | The default is very large, so normally there is no practical limit. If you |
931 | The default value is very large, so there is no practical limit on the |
811 | queue up many requests in a loop it often improves speed if you set |
932 | number of outstanding requests. |
812 | this to a relatively low number, such as C<100>. |
|
|
813 | |
933 | |
814 | This function does not work well together with C<aio_group>'s, and their |
934 | You can still queue as many requests as you want. Therefore, |
815 | feeder interface is better suited to limiting concurrency, so do not use |
935 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
816 | this function. |
936 | as a stop gap to shield against fatal memory overflow (with large values). |
817 | |
|
|
818 | Under normal circumstances you don't need to call this function. |
|
|
819 | |
937 | |
820 | =back |
938 | =back |
821 | |
939 | |
822 | =cut |
940 | =cut |
823 | |
941 | |
… | |
… | |
850 | This module should do "the right thing" when the process using it forks: |
968 | This module should do "the right thing" when the process using it forks: |
851 | |
969 | |
852 | Before the fork, IO::AIO enters a quiescent state where no requests |
970 | Before the fork, IO::AIO enters a quiescent state where no requests |
853 | can be added in other threads and no results will be processed. After |
971 | can be added in other threads and no results will be processed. After |
854 | the fork the parent simply leaves the quiescent state and continues |
972 | the fork the parent simply leaves the quiescent state and continues |
855 | request/result processing, while the child clears the request/result |
973 | request/result processing, while the child frees the request/result queue |
856 | queue (so the requests started before the fork will only be handled in |
974 | (so that the requests started before the fork will only be handled in the |
857 | the parent). Threads will be started on demand until the limit ste in the |
975 | parent). Threads will be started on demand until the limit set in the |
858 | parent process has been reached again. |
976 | parent process has been reached again. |
859 | |
977 | |
860 | In short: the parent will, after a short pause, continue as if fork had |
978 | In short: the parent will, after a short pause, continue as if fork had |
861 | not been called, while the child will act as if IO::AIO has not been used |
979 | not been called, while the child will act as if IO::AIO has not been used |
862 | yet. |
980 | yet. |
863 | |
981 | |
864 | =head2 MEMORY USAGE |
982 | =head2 MEMORY USAGE |
865 | |
983 | |
|
|
984 | Per-request usage: |
|
|
985 | |
866 | Each aio request uses - depending on your architecture - around 128 bytes |
986 | Each aio request uses - depending on your architecture - around 100-200 |
867 | of memory. In addition, stat requests need a stat buffer (possibly a few |
987 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
868 | hundred bytes). Perl scalars and other data passed into aio requests will |
988 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
869 | also be locked. |
989 | scalars and other data passed into aio requests will also be locked and |
|
|
990 | will consume memory till the request has entered the done state. |
870 | |
991 | |
871 | This is now awfully much, so queuing lots of requests is not usually a |
992 | This is now awfully much, so queuing lots of requests is not usually a |
872 | problem. |
993 | problem. |
873 | |
994 | |
874 | Each thread needs a stack area which is usually around 16k, sometimes much |
995 | Per-thread usage: |
875 | larger, depending on the OS. |
996 | |
|
|
997 | In the execution phase, some aio requests require more memory for |
|
|
998 | temporary buffers, and each thread requires a stack and other data |
|
|
999 | structures (usually around 16k-128k, depending on the OS). |
|
|
1000 | |
|
|
1001 | =head1 KNOWN BUGS |
|
|
1002 | |
|
|
1003 | Known bugs will be fixed in the next release. |
876 | |
1004 | |
877 | =head1 SEE ALSO |
1005 | =head1 SEE ALSO |
878 | |
1006 | |
879 | L<Coro>, L<Linux::AIO> (obsolete). |
1007 | L<Coro::AIO>. |
880 | |
1008 | |
881 | =head1 AUTHOR |
1009 | =head1 AUTHOR |
882 | |
1010 | |
883 | Marc Lehmann <schmorp@schmorp.de> |
1011 | Marc Lehmann <schmorp@schmorp.de> |
884 | http://home.schmorp.de/ |
1012 | http://home.schmorp.de/ |