… | |
… | |
15 | |
15 | |
16 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
16 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
17 | $_[0] > 0 or die "read error: $!"; |
17 | $_[0] > 0 or die "read error: $!"; |
18 | }; |
18 | }; |
19 | |
19 | |
20 | use IO::AIO 2; # version has aio objects |
20 | # version 2+ has request and group objects |
|
|
21 | use IO::AIO 2; |
21 | |
22 | |
22 | my $req = aio_unlink "/tmp/file", sub { }; |
23 | my $req = aio_unlink "/tmp/file", sub { }; |
23 | $req->cancel; # cancel request if still in queue |
24 | $req->cancel; # cancel request if still in queue |
24 | |
25 | |
25 | # AnyEvent |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
|
|
27 | add $grp aio_stat "..." for ...; |
|
|
28 | |
|
|
29 | # AnyEvent integration |
26 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
30 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
27 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
31 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
28 | |
32 | |
29 | # Event |
33 | # Event integration |
30 | Event->io (fd => IO::AIO::poll_fileno, |
34 | Event->io (fd => IO::AIO::poll_fileno, |
31 | poll => 'r', |
35 | poll => 'r', |
32 | cb => \&IO::AIO::poll_cb); |
36 | cb => \&IO::AIO::poll_cb); |
33 | |
37 | |
34 | # Glib/Gtk2 |
38 | # Glib/Gtk2 integration |
35 | add_watch Glib::IO IO::AIO::poll_fileno, |
39 | add_watch Glib::IO IO::AIO::poll_fileno, |
36 | in => sub { IO::AIO::poll_cb; 1 }; |
40 | in => sub { IO::AIO::poll_cb; 1 }; |
37 | |
41 | |
38 | # Tk |
42 | # Tk integration |
39 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
43 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
40 | readable => \&IO::AIO::poll_cb); |
44 | readable => \&IO::AIO::poll_cb); |
41 | |
45 | |
42 | # Danga::Socket |
46 | # Danga::Socket integration |
43 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
47 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
44 | \&IO::AIO::poll_cb); |
48 | \&IO::AIO::poll_cb); |
45 | |
|
|
46 | |
49 | |
47 | =head1 DESCRIPTION |
50 | =head1 DESCRIPTION |
48 | |
51 | |
49 | This module implements asynchronous I/O using whatever means your |
52 | This module implements asynchronous I/O using whatever means your |
50 | operating system supports. |
53 | operating system supports. |
… | |
… | |
71 | use strict 'vars'; |
74 | use strict 'vars'; |
72 | |
75 | |
73 | use base 'Exporter'; |
76 | use base 'Exporter'; |
74 | |
77 | |
75 | BEGIN { |
78 | BEGIN { |
76 | our $VERSION = '1.99'; |
79 | our $VERSION = '2.0'; |
77 | |
80 | |
78 | our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
81 | our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
79 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
82 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
80 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
83 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
81 | aio_group); |
84 | aio_group aio_nop); |
82 | our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
85 | our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
83 | |
86 | |
84 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
87 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
85 | |
88 | |
86 | require XSLoader; |
89 | require XSLoader; |
… | |
… | |
100 | syscall has been executed asynchronously. |
103 | syscall has been executed asynchronously. |
101 | |
104 | |
102 | All functions expecting a filehandle keep a copy of the filehandle |
105 | All functions expecting a filehandle keep a copy of the filehandle |
103 | internally until the request has finished. |
106 | internally until the request has finished. |
104 | |
107 | |
105 | All non-composite requests (requests that are not broken down into |
|
|
106 | multiple requests) return objects of type L<IO::AIO::REQ> that allow |
108 | All requests return objects of type L<IO::AIO::REQ> that allow further |
107 | further manipulation of running requests. |
109 | manipulation of those requests while they are in-flight. |
108 | |
110 | |
109 | The pathnames you pass to these routines I<must> be absolute and |
111 | The pathnames you pass to these routines I<must> be absolute and |
110 | encoded in byte form. The reason for the former is that at the time the |
112 | encoded in byte form. The reason for the former is that at the time the |
111 | request is being executed, the current working directory could have |
113 | request is being executed, the current working directory could have |
112 | changed. Alternatively, you can make sure that you never change the |
114 | changed. Alternatively, you can make sure that you never change the |
… | |
… | |
180 | print "read $_[0] bytes: <$buffer>\n"; |
182 | print "read $_[0] bytes: <$buffer>\n"; |
181 | }; |
183 | }; |
182 | |
184 | |
183 | =item aio_move $srcpath, $dstpath, $callback->($status) |
185 | =item aio_move $srcpath, $dstpath, $callback->($status) |
184 | |
186 | |
|
|
187 | [EXPERIMENTAL due to internal aio_group use] |
|
|
188 | |
185 | Try to move the I<file> (directories not supported as either source or |
189 | Try to move the I<file> (directories not supported as either source or |
186 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
190 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
187 | the C<0> (error) or C<-1> ok. |
191 | the C<0> (error) or C<-1> ok. |
188 | |
192 | |
189 | This is a composite request that tries to rename(2) the file first. If |
193 | This is a composite request that tries to rename(2) the file first. If |
… | |
… | |
199 | =cut |
203 | =cut |
200 | |
204 | |
201 | sub aio_move($$$) { |
205 | sub aio_move($$$) { |
202 | my ($src, $dst, $cb) = @_; |
206 | my ($src, $dst, $cb) = @_; |
203 | |
207 | |
|
|
208 | my $grp = aio_group $cb; |
|
|
209 | |
204 | aio_rename $src, $dst, sub { |
210 | add $grp aio_rename $src, $dst, sub { |
205 | if ($_[0] && $! == EXDEV) { |
211 | if ($_[0] && $! == EXDEV) { |
206 | aio_open $src, O_RDONLY, 0, sub { |
212 | add $grp aio_open $src, O_RDONLY, 0, sub { |
207 | if (my $src_fh = $_[0]) { |
213 | if (my $src_fh = $_[0]) { |
208 | my @stat = stat $src_fh; |
214 | my @stat = stat $src_fh; |
209 | |
215 | |
210 | aio_open $dst, O_WRONLY, 0200, sub { |
216 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
211 | if (my $dst_fh = $_[0]) { |
217 | if (my $dst_fh = $_[0]) { |
212 | aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
218 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
213 | close $src_fh; |
219 | close $src_fh; |
214 | |
220 | |
215 | if ($_[0] == $stat[7]) { |
221 | if ($_[0] == $stat[7]) { |
216 | utime $stat[8], $stat[9], $dst; |
222 | utime $stat[8], $stat[9], $dst; |
217 | chmod $stat[2] & 07777, $dst_fh; |
223 | chmod $stat[2] & 07777, $dst_fh; |
218 | chown $stat[4], $stat[5], $dst_fh; |
224 | chown $stat[4], $stat[5], $dst_fh; |
219 | close $dst_fh; |
225 | close $dst_fh; |
220 | |
226 | |
221 | aio_unlink $src, sub { |
227 | add $grp aio_unlink $src, sub { |
222 | $cb->($_[0]); |
228 | $grp->result ($_[0]); |
223 | }; |
229 | }; |
224 | } else { |
230 | } else { |
225 | my $errno = $!; |
231 | my $errno = $!; |
226 | aio_unlink $dst, sub { |
232 | add $grp aio_unlink $dst, sub { |
227 | $! = $errno; |
233 | $! = $errno; |
228 | $cb->(-1); |
234 | $grp->result (-1); |
229 | }; |
235 | }; |
230 | } |
236 | } |
231 | }; |
237 | }; |
232 | } else { |
238 | } else { |
233 | $cb->(-1); |
239 | $grp->result (-1); |
234 | } |
240 | } |
235 | }, |
241 | }, |
236 | |
242 | |
237 | } else { |
243 | } else { |
238 | $cb->(-1); |
244 | $grp->result (-1); |
239 | } |
245 | } |
240 | }; |
246 | }; |
241 | } else { |
247 | } else { |
242 | $cb->($_[0]); |
248 | $grp->result ($_[0]); |
243 | } |
249 | } |
244 | }; |
250 | }; |
|
|
251 | |
|
|
252 | $grp |
245 | } |
253 | } |
246 | |
254 | |
247 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
255 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
248 | |
256 | |
249 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
257 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
… | |
… | |
337 | The callback a single argument which is either C<undef> or an array-ref |
345 | The callback a single argument which is either C<undef> or an array-ref |
338 | with the filenames. |
346 | with the filenames. |
339 | |
347 | |
340 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
348 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
341 | |
349 | |
|
|
350 | [EXPERIMENTAL due to internal aio_group use] |
|
|
351 | |
342 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
352 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
343 | separate the entries of directory C<$path> into two sets of names, ones |
353 | separate the entries of directory C<$path> into two sets of names, ones |
344 | you can recurse into (directories or links to them), and ones you cannot |
354 | you can recurse into (directories or links to them), and ones you cannot |
345 | recurse into (everything else). |
355 | recurse into (everything else). |
346 | |
356 | |
347 | C<aio_scandir> is a composite request that consists of many sub |
357 | C<aio_scandir> is a composite request that creates of many sub requests_ |
348 | requests. C<$maxreq> specifies the maximum number of outstanding aio |
358 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
349 | requests that this function generates. If it is C<< <= 0 >>, then a |
359 | this function generates. If it is C<< <= 0 >>, then a suitable default |
350 | suitable default will be chosen (currently 8). |
360 | will be chosen (currently 6). |
351 | |
361 | |
352 | On error, the callback is called without arguments, otherwise it receives |
362 | On error, the callback is called without arguments, otherwise it receives |
353 | two array-refs with path-relative entry names. |
363 | two array-refs with path-relative entry names. |
354 | |
364 | |
355 | Example: |
365 | Example: |
… | |
… | |
392 | =cut |
402 | =cut |
393 | |
403 | |
394 | sub aio_scandir($$$) { |
404 | sub aio_scandir($$$) { |
395 | my ($path, $maxreq, $cb) = @_; |
405 | my ($path, $maxreq, $cb) = @_; |
396 | |
406 | |
|
|
407 | my $grp = aio_group $cb; |
|
|
408 | |
397 | $maxreq = 8 if $maxreq <= 0; |
409 | $maxreq = 6 if $maxreq <= 0; |
398 | |
410 | |
399 | # stat once |
411 | # stat once |
400 | aio_stat $path, sub { |
412 | add $grp aio_stat $path, sub { |
401 | return $cb->() if $_[0]; |
413 | return $grp->result () if $_[0]; |
402 | my $now = time; |
414 | my $now = time; |
403 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
415 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
404 | |
416 | |
405 | # read the directory entries |
417 | # read the directory entries |
406 | aio_readdir $path, sub { |
418 | add $grp aio_readdir $path, sub { |
407 | my $entries = shift |
419 | my $entries = shift |
408 | or return $cb->(); |
420 | or return $grp->result (); |
409 | |
421 | |
410 | # stat the dir another time |
422 | # stat the dir another time |
411 | aio_stat $path, sub { |
423 | add $grp aio_stat $path, sub { |
412 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
424 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
413 | |
425 | |
414 | my $ndirs; |
426 | my $ndirs; |
415 | |
427 | |
416 | # take the slow route if anything looks fishy |
428 | # take the slow route if anything looks fishy |
… | |
… | |
418 | $ndirs = -1; |
430 | $ndirs = -1; |
419 | } else { |
431 | } else { |
420 | # if nlink == 2, we are finished |
432 | # if nlink == 2, we are finished |
421 | # on non-posix-fs's, we rely on nlink < 2 |
433 | # on non-posix-fs's, we rely on nlink < 2 |
422 | $ndirs = (stat _)[3] - 2 |
434 | $ndirs = (stat _)[3] - 2 |
423 | or return $cb->([], $entries); |
435 | or return $grp->result ([], $entries); |
424 | } |
436 | } |
425 | |
437 | |
426 | # sort into likely dirs and likely nondirs |
438 | # sort into likely dirs and likely nondirs |
427 | # dirs == files without ".", short entries first |
439 | # dirs == files without ".", short entries first |
428 | $entries = [map $_->[0], |
440 | $entries = [map $_->[0], |
… | |
… | |
433 | my (@dirs, @nondirs); |
445 | my (@dirs, @nondirs); |
434 | |
446 | |
435 | my ($statcb, $schedcb); |
447 | my ($statcb, $schedcb); |
436 | my $nreq = 0; |
448 | my $nreq = 0; |
437 | |
449 | |
|
|
450 | my $statgrp = add $grp aio_group; |
|
|
451 | |
438 | $schedcb = sub { |
452 | $schedcb = sub { |
439 | if (@$entries) { |
453 | if (@$entries) { |
440 | if ($nreq < $maxreq) { |
454 | if ($nreq < $maxreq) { |
441 | my $ent = pop @$entries; |
455 | my $ent = pop @$entries; |
442 | $nreq++; |
456 | $nreq++; |
443 | aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
457 | add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
444 | } |
458 | } |
445 | } elsif (!$nreq) { |
459 | } elsif (!$nreq) { |
446 | # finished |
460 | # finished |
|
|
461 | $statgrp->cancel; |
447 | undef $statcb; |
462 | undef $statcb; |
448 | undef $schedcb; |
463 | undef $schedcb; |
449 | $cb->(\@dirs, \@nondirs) if $cb; |
464 | $grp->result (\@dirs, \@nondirs); |
450 | undef $cb; |
|
|
451 | } |
465 | } |
452 | }; |
466 | }; |
453 | $statcb = sub { |
467 | $statcb = sub { |
454 | my ($status, $entry) = @_; |
468 | my ($status, $entry) = @_; |
455 | |
469 | |
… | |
… | |
457 | $nreq--; |
471 | $nreq--; |
458 | push @nondirs, $entry; |
472 | push @nondirs, $entry; |
459 | &$schedcb; |
473 | &$schedcb; |
460 | } else { |
474 | } else { |
461 | # need to check for real directory |
475 | # need to check for real directory |
462 | aio_lstat "$path/$entry", sub { |
476 | add $grp aio_lstat "$path/$entry", sub { |
463 | $nreq--; |
477 | $nreq--; |
464 | |
478 | |
465 | if (-d _) { |
479 | if (-d _) { |
466 | push @dirs, $entry; |
480 | push @dirs, $entry; |
467 | |
481 | |
… | |
… | |
480 | |
494 | |
481 | &$schedcb while @$entries && $nreq < $maxreq; |
495 | &$schedcb while @$entries && $nreq < $maxreq; |
482 | }; |
496 | }; |
483 | }; |
497 | }; |
484 | }; |
498 | }; |
|
|
499 | |
|
|
500 | $grp |
485 | } |
501 | } |
486 | |
502 | |
487 | =item aio_fsync $fh, $callback->($status) |
503 | =item aio_fsync $fh, $callback->($status) |
488 | |
504 | |
489 | Asynchronously call fsync on the given filehandle and call the callback |
505 | Asynchronously call fsync on the given filehandle and call the callback |
… | |
… | |
495 | callback with the fdatasync result code. |
511 | callback with the fdatasync result code. |
496 | |
512 | |
497 | If this call isn't available because your OS lacks it or it couldn't be |
513 | If this call isn't available because your OS lacks it or it couldn't be |
498 | detected, it will be emulated by calling C<fsync> instead. |
514 | detected, it will be emulated by calling C<fsync> instead. |
499 | |
515 | |
500 | =item aio_group $callback->() |
516 | =item aio_group $callback->(...) |
501 | |
517 | |
|
|
518 | [EXPERIMENTAL] |
|
|
519 | |
|
|
520 | 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 |
|
|
522 | many requests into a single, composite, request. |
|
|
523 | |
|
|
524 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
525 | for more info. |
|
|
526 | |
|
|
527 | Example: |
|
|
528 | |
|
|
529 | my $grp = aio_group sub { |
|
|
530 | print "all stats done\n"; |
|
|
531 | }; |
|
|
532 | |
|
|
533 | add $grp |
|
|
534 | (aio_stat ...), |
|
|
535 | (aio_stat ...), |
|
|
536 | ...; |
|
|
537 | |
|
|
538 | =item aio_nop $callback->() |
|
|
539 | |
|
|
540 | 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 |
|
|
542 | that finishing the requests in the group depends on executing the given |
|
|
543 | code. |
|
|
544 | |
502 | =item aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
545 | =item IO::AIO::aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
503 | |
546 | |
504 | Mainly used for debugging and benchmarking, this aio request puts one of |
547 | Mainly used for debugging and benchmarking, this aio request puts one of |
505 | the request workers to sleep for the given time. |
548 | the request workers to sleep for the given time. |
|
|
549 | |
|
|
550 | While it is theoretically handy to have simple I/O scheduling requests |
|
|
551 | like sleep and file handle readable/writable, the overhead this creates |
|
|
552 | is immense, so do not use this function except to put your application |
|
|
553 | under artificial I/O pressure. |
506 | |
554 | |
507 | =back |
555 | =back |
508 | |
556 | |
509 | =head2 IO::AIO::REQ CLASS |
557 | =head2 IO::AIO::REQ CLASS |
510 | |
558 | |
… | |
… | |
529 | untouched. That means that requests that currently execute will not be |
577 | untouched. That means that requests that currently execute will not be |
530 | stopped and resources held by the request will not be freed prematurely. |
578 | stopped and resources held by the request will not be freed prematurely. |
531 | |
579 | |
532 | =back |
580 | =back |
533 | |
581 | |
|
|
582 | =head2 IO::AIO::GRP CLASS |
|
|
583 | |
|
|
584 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
585 | objects of this class, too. |
|
|
586 | |
|
|
587 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
588 | aio requests. |
|
|
589 | |
|
|
590 | You create one by calling the C<aio_group> constructing function with a |
|
|
591 | callback that will be called when all contained requests have entered the |
|
|
592 | C<done> state: |
|
|
593 | |
|
|
594 | my $grp = aio_group sub { |
|
|
595 | print "all requests are done\n"; |
|
|
596 | }; |
|
|
597 | |
|
|
598 | You add requests by calling the C<add> method with one or more |
|
|
599 | C<IO::AIO::REQ> objects: |
|
|
600 | |
|
|
601 | $grp->add (aio_unlink "..."); |
|
|
602 | |
|
|
603 | add $grp aio_stat "...", sub { |
|
|
604 | $_[0] or return $grp->result ("error"); |
|
|
605 | |
|
|
606 | # add another request dynamically, if first succeeded |
|
|
607 | add $grp aio_open "...", sub { |
|
|
608 | $grp->result ("ok"); |
|
|
609 | }; |
|
|
610 | }; |
|
|
611 | |
|
|
612 | This makes it very easy to create composite requests (see the source of |
|
|
613 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
614 | |
|
|
615 | =over 4 |
|
|
616 | |
|
|
617 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
618 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
619 | |
|
|
620 | =item * They can be canceled like any other request. Canceling will cancel not |
|
|
621 | only the request itself, but also all requests it contains. |
|
|
622 | |
|
|
623 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
624 | |
|
|
625 | =item * You must not add requests to a group from within the group callback (or |
|
|
626 | any later time). |
|
|
627 | |
|
|
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 |
|
|
633 | |
|
|
634 | 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 |
|
|
636 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
637 | exist. |
|
|
638 | |
|
|
639 | That means after creating a group you have some time to add requests. And |
|
|
640 | in the callbacks of those requests, you can add further requests to the |
|
|
641 | group. And only when all those requests have finished will the the group |
|
|
642 | itself finish. |
|
|
643 | |
|
|
644 | =over 4 |
|
|
645 | |
|
|
646 | =item $grp->add (...) |
|
|
647 | |
|
|
648 | =item add $grp ... |
|
|
649 | |
|
|
650 | 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 |
|
|
652 | dependencies. |
|
|
653 | |
|
|
654 | Returns all its arguments. |
|
|
655 | |
|
|
656 | =item $grp->result (...) |
|
|
657 | |
|
|
658 | 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. |
|
|
660 | |
|
|
661 | =item $grp->set_feeder ($callback->($grp)) |
|
|
662 | |
|
|
663 | [VERY EXPERIMENTAL] |
|
|
664 | |
|
|
665 | 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, |
|
|
667 | 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 |
|
|
669 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
|
|
670 | requests, delaying any later requests for a long time. |
|
|
671 | |
|
|
672 | 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 |
|
|
674 | feeder will be called whenever there are few enough (see C<feeder_limit>, |
|
|
675 | below) requests active in the group itself and is expected to queue more |
|
|
676 | requests. |
|
|
677 | |
|
|
678 | The feeder can queue as many requests as it likes (i.e. C<add> does not |
|
|
679 | impose any limits). |
|
|
680 | |
|
|
681 | If the feeder does not queue more requests when called, it will be |
|
|
682 | automatically removed from the group. |
|
|
683 | |
|
|
684 | If the feeder limit is C<0>, it will be set to C<2> automatically. |
|
|
685 | |
|
|
686 | Example: |
|
|
687 | |
|
|
688 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
689 | |
|
|
690 | my $grp = aio_group sub { print "finished\n" }; |
|
|
691 | $grp->feeder_limit (4); |
|
|
692 | $grp->set_feeder (sub { |
|
|
693 | my $file = pop @files |
|
|
694 | or return; |
|
|
695 | |
|
|
696 | add $grp aio_stat $file, sub { ... }; |
|
|
697 | }); |
|
|
698 | |
|
|
699 | =item $grp->feeder_limit ($num) |
|
|
700 | |
|
|
701 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
702 | the group contains less than this many requests. |
|
|
703 | |
|
|
704 | Setting the limit to C<0> will pause the feeding process. |
|
|
705 | |
|
|
706 | =back |
|
|
707 | |
534 | =head2 SUPPORT FUNCTIONS |
708 | =head2 SUPPORT FUNCTIONS |
535 | |
709 | |
536 | =over 4 |
710 | =over 4 |
537 | |
711 | |
538 | =item $fileno = IO::AIO::poll_fileno |
712 | =item $fileno = IO::AIO::poll_fileno |
… | |
… | |
593 | IO::AIO::poll_wait, IO::AIO::poll_cb |
767 | IO::AIO::poll_wait, IO::AIO::poll_cb |
594 | if IO::AIO::nreqs; |
768 | if IO::AIO::nreqs; |
595 | |
769 | |
596 | =item IO::AIO::min_parallel $nthreads |
770 | =item IO::AIO::min_parallel $nthreads |
597 | |
771 | |
598 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
772 | Set the minimum number of AIO threads to C<$nthreads>. The current |
599 | is C<4>, which means four asynchronous operations can be done at one time |
773 | default is C<8>, which means eight asynchronous operations can execute |
600 | (the number of outstanding operations, however, is unlimited). |
774 | concurrently at any one time (the number of outstanding requests, |
|
|
775 | however, is unlimited). |
601 | |
776 | |
602 | IO::AIO starts threads only on demand, when an AIO request is queued and |
777 | IO::AIO starts threads only on demand, when an AIO request is queued and |
603 | no free thread exists. |
778 | no free thread exists. |
604 | |
779 | |
605 | It is recommended to keep the number of threads low, as some Linux |
780 | It is recommended to keep the number of threads relatively low, as some |
606 | kernel versions will scale negatively with the number of threads (higher |
781 | Linux kernel versions will scale negatively with the number of threads |
607 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
782 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
608 | threads should be fine. |
783 | versions, 4-32 threads should be fine. |
609 | |
784 | |
610 | Under most circumstances you don't need to call this function, as the |
785 | Under most circumstances you don't need to call this function, as the |
611 | module selects a default that is suitable for low to moderate load. |
786 | module selects a default that is suitable for low to moderate load. |
612 | |
787 | |
613 | =item IO::AIO::max_parallel $nthreads |
788 | =item IO::AIO::max_parallel $nthreads |
… | |
… | |
624 | |
799 | |
625 | Under normal circumstances you don't need to call this function. |
800 | Under normal circumstances you don't need to call this function. |
626 | |
801 | |
627 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
802 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
628 | |
803 | |
|
|
804 | [DEPRECATED] |
|
|
805 | |
629 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
806 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
630 | try to queue up more than this number of requests, the caller will block until |
807 | try to queue up more than this number of requests, the caller will block until |
631 | some requests have been handled. |
808 | some requests have been handled. |
632 | |
809 | |
633 | The default is very large, so normally there is no practical limit. If you |
810 | The default is very large, so normally there is no practical limit. If you |
634 | queue up many requests in a loop it often improves speed if you set |
811 | queue up many requests in a loop it often improves speed if you set |
635 | this to a relatively low number, such as C<100>. |
812 | this to a relatively low number, such as C<100>. |
|
|
813 | |
|
|
814 | This function does not work well together with C<aio_group>'s, and their |
|
|
815 | feeder interface is better suited to limiting concurrency, so do not use |
|
|
816 | this function. |
636 | |
817 | |
637 | Under normal circumstances you don't need to call this function. |
818 | Under normal circumstances you don't need to call this function. |
638 | |
819 | |
639 | =back |
820 | =back |
640 | |
821 | |
… | |
… | |
654 | or return undef; |
835 | or return undef; |
655 | |
836 | |
656 | *$sym |
837 | *$sym |
657 | } |
838 | } |
658 | |
839 | |
659 | min_parallel 4; |
840 | min_parallel 8; |
660 | |
841 | |
661 | END { |
842 | END { |
662 | max_parallel 0; |
843 | max_parallel 0; |
663 | } |
844 | } |
664 | |
845 | |
… | |
… | |
678 | |
859 | |
679 | In short: the parent will, after a short pause, continue as if fork had |
860 | In short: the parent will, after a short pause, continue as if fork had |
680 | not been called, while the child will act as if IO::AIO has not been used |
861 | not been called, while the child will act as if IO::AIO has not been used |
681 | yet. |
862 | yet. |
682 | |
863 | |
|
|
864 | =head2 MEMORY USAGE |
|
|
865 | |
|
|
866 | Each aio request uses - depending on your architecture - around 128 bytes |
|
|
867 | of memory. In addition, stat requests need a stat buffer (possibly a few |
|
|
868 | hundred bytes). Perl scalars and other data passed into aio requests will |
|
|
869 | also be locked. |
|
|
870 | |
|
|
871 | This is now awfully much, so queuing lots of requests is not usually a |
|
|
872 | problem. |
|
|
873 | |
|
|
874 | Each thread needs a stack area which is usually around 16k, sometimes much |
|
|
875 | larger, depending on the OS. |
|
|
876 | |
683 | =head1 SEE ALSO |
877 | =head1 SEE ALSO |
684 | |
878 | |
685 | L<Coro>, L<Linux::AIO> (obsolete). |
879 | L<Coro>, L<Linux::AIO> (obsolete). |
686 | |
880 | |
687 | =head1 AUTHOR |
881 | =head1 AUTHOR |