… | |
… | |
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 | |
|
|
23 | aioreq_pri 4; # give next request a very high priority |
22 | my $req = aio_unlink "/tmp/file", sub { }; |
24 | my $req = aio_unlink "/tmp/file", sub { }; |
23 | $req->cancel; # cancel request if still in queue |
25 | $req->cancel; # cancel request if still in queue |
24 | |
26 | |
25 | # AnyEvent |
27 | my $grp = aio_group sub { print "all stats done\n" }; |
|
|
28 | add $grp aio_stat "..." for ...; |
|
|
29 | |
|
|
30 | # AnyEvent integration |
26 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
31 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
27 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
32 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
28 | |
33 | |
29 | # Event |
34 | # Event integration |
30 | Event->io (fd => IO::AIO::poll_fileno, |
35 | Event->io (fd => IO::AIO::poll_fileno, |
31 | poll => 'r', |
36 | poll => 'r', |
32 | cb => \&IO::AIO::poll_cb); |
37 | cb => \&IO::AIO::poll_cb); |
33 | |
38 | |
34 | # Glib/Gtk2 |
39 | # Glib/Gtk2 integration |
35 | add_watch Glib::IO IO::AIO::poll_fileno, |
40 | add_watch Glib::IO IO::AIO::poll_fileno, |
36 | in => sub { IO::AIO::poll_cb; 1 }; |
41 | in => sub { IO::AIO::poll_cb; 1 }; |
37 | |
42 | |
38 | # Tk |
43 | # Tk integration |
39 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
44 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
40 | readable => \&IO::AIO::poll_cb); |
45 | readable => \&IO::AIO::poll_cb); |
41 | |
46 | |
42 | # Danga::Socket |
47 | # Danga::Socket integration |
43 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
48 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
44 | \&IO::AIO::poll_cb); |
49 | \&IO::AIO::poll_cb); |
45 | |
50 | |
46 | |
|
|
47 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
48 | |
52 | |
49 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
50 | operating system supports. |
54 | operating system supports. |
51 | |
55 | |
52 | 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 |
53 | 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 |
54 | 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 |
55 | 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 |
56 | aio functions available on many operating systems. However, they are often |
60 | functions available on many operating systems. However, they are often |
57 | 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 |
58 | 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 |
59 | 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. |
60 | |
65 | |
61 | 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-) |
62 | currently not reentrant, so use appropriate locking yourself, always call |
67 | threads, it is currently not reentrant in any way, so use appropriate |
63 | 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 |
64 | 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). |
65 | |
120 | |
66 | =cut |
121 | =cut |
67 | |
122 | |
68 | package IO::AIO; |
123 | package IO::AIO; |
69 | |
124 | |
… | |
… | |
71 | use strict 'vars'; |
126 | use strict 'vars'; |
72 | |
127 | |
73 | use base 'Exporter'; |
128 | use base 'Exporter'; |
74 | |
129 | |
75 | BEGIN { |
130 | BEGIN { |
76 | our $VERSION = '1.99'; |
131 | our $VERSION = '2.0'; |
77 | |
132 | |
78 | 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 |
79 | 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 |
80 | 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 |
81 | aio_group); |
136 | aio_group aio_nop); |
82 | 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); |
83 | |
140 | |
84 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
141 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
85 | |
142 | |
86 | require XSLoader; |
143 | require XSLoader; |
87 | XSLoader::load ("IO::AIO", $VERSION); |
144 | XSLoader::load ("IO::AIO", $VERSION); |
… | |
… | |
100 | syscall has been executed asynchronously. |
157 | syscall has been executed asynchronously. |
101 | |
158 | |
102 | All functions expecting a filehandle keep a copy of the filehandle |
159 | All functions expecting a filehandle keep a copy of the filehandle |
103 | internally until the request has finished. |
160 | internally until the request has finished. |
104 | |
161 | |
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 |
162 | All requests return objects of type L<IO::AIO::REQ> that allow further |
107 | further manipulation of running requests. |
163 | manipulation of those requests while they are in-flight. |
108 | |
164 | |
109 | The pathnames you pass to these routines I<must> be absolute and |
165 | 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 |
166 | 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 |
167 | request is being executed, the current working directory could have |
112 | changed. Alternatively, you can make sure that you never change the |
168 | changed. Alternatively, you can make sure that you never change the |
… | |
… | |
118 | 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 |
119 | 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) |
120 | use something else. |
176 | use something else. |
121 | |
177 | |
122 | =over 4 |
178 | =over 4 |
|
|
179 | |
|
|
180 | =item aioreq_pri $pri |
|
|
181 | |
|
|
182 | Sets the priority for the next aio request. The default priority |
|
|
183 | is C<0>, the minimum and maximum priorities are C<-4> and C<4>, |
|
|
184 | respectively. Requests with higher priority will be serviced first. |
|
|
185 | |
|
|
186 | The priority will be reset to C<0> after each call to one of the C<aio_> |
|
|
187 | functions. |
|
|
188 | |
|
|
189 | Example: open a file with low priority, then read something from it with |
|
|
190 | higher priority so the read request is serviced before other low priority |
|
|
191 | open requests (potentially spamming the cache): |
|
|
192 | |
|
|
193 | aioreq_pri -3; |
|
|
194 | aio_open ..., sub { |
|
|
195 | return unless $_[0]; |
|
|
196 | |
|
|
197 | aioreq_pri -2; |
|
|
198 | aio_read $_[0], ..., sub { |
|
|
199 | ... |
|
|
200 | }; |
|
|
201 | }; |
|
|
202 | |
|
|
203 | =item aioreq_nice $pri_adjust |
|
|
204 | |
|
|
205 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
|
206 | priority, so effects are cumulative. |
123 | |
207 | |
124 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
208 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
125 | |
209 | |
126 | Asynchronously open or create a file and call the callback with a newly |
210 | Asynchronously open or create a file and call the callback with a newly |
127 | created filehandle for the file. |
211 | created filehandle for the file. |
… | |
… | |
199 | =cut |
283 | =cut |
200 | |
284 | |
201 | sub aio_move($$$) { |
285 | sub aio_move($$$) { |
202 | my ($src, $dst, $cb) = @_; |
286 | my ($src, $dst, $cb) = @_; |
203 | |
287 | |
|
|
288 | my $grp = aio_group $cb; |
|
|
289 | |
204 | aio_rename $src, $dst, sub { |
290 | add $grp aio_rename $src, $dst, sub { |
205 | if ($_[0] && $! == EXDEV) { |
291 | if ($_[0] && $! == EXDEV) { |
206 | aio_open $src, O_RDONLY, 0, sub { |
292 | add $grp aio_open $src, O_RDONLY, 0, sub { |
207 | if (my $src_fh = $_[0]) { |
293 | if (my $src_fh = $_[0]) { |
208 | my @stat = stat $src_fh; |
294 | my @stat = stat $src_fh; |
209 | |
295 | |
210 | aio_open $dst, O_WRONLY, 0200, sub { |
296 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
211 | if (my $dst_fh = $_[0]) { |
297 | if (my $dst_fh = $_[0]) { |
212 | aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
298 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
213 | close $src_fh; |
299 | close $src_fh; |
214 | |
300 | |
215 | if ($_[0] == $stat[7]) { |
301 | if ($_[0] == $stat[7]) { |
216 | utime $stat[8], $stat[9], $dst; |
302 | utime $stat[8], $stat[9], $dst; |
217 | chmod $stat[2] & 07777, $dst_fh; |
303 | chmod $stat[2] & 07777, $dst_fh; |
218 | chown $stat[4], $stat[5], $dst_fh; |
304 | chown $stat[4], $stat[5], $dst_fh; |
219 | close $dst_fh; |
305 | close $dst_fh; |
220 | |
306 | |
221 | aio_unlink $src, sub { |
307 | add $grp aio_unlink $src, sub { |
222 | $cb->($_[0]); |
308 | $grp->result ($_[0]); |
223 | }; |
309 | }; |
224 | } else { |
310 | } else { |
225 | my $errno = $!; |
311 | my $errno = $!; |
226 | aio_unlink $dst, sub { |
312 | add $grp aio_unlink $dst, sub { |
227 | $! = $errno; |
313 | $! = $errno; |
228 | $cb->(-1); |
314 | $grp->result (-1); |
229 | }; |
315 | }; |
230 | } |
316 | } |
231 | }; |
317 | }; |
232 | } else { |
318 | } else { |
233 | $cb->(-1); |
319 | $grp->result (-1); |
234 | } |
320 | } |
235 | }, |
321 | }, |
236 | |
322 | |
237 | } else { |
323 | } else { |
238 | $cb->(-1); |
324 | $grp->result (-1); |
239 | } |
325 | } |
240 | }; |
326 | }; |
241 | } else { |
327 | } else { |
242 | $cb->($_[0]); |
328 | $grp->result ($_[0]); |
243 | } |
329 | } |
244 | }; |
330 | }; |
|
|
331 | |
|
|
332 | $grp |
245 | } |
333 | } |
246 | |
334 | |
247 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
335 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
248 | |
336 | |
249 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
337 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
… | |
… | |
338 | with the filenames. |
426 | with the filenames. |
339 | |
427 | |
340 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
428 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
341 | |
429 | |
342 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
430 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
343 | separate the entries of directory C<$path> into two sets of names, ones |
431 | efficiently separate the entries of directory C<$path> into two sets of |
344 | you can recurse into (directories or links to them), and ones you cannot |
432 | names, directories you can recurse into (directories), and ones you cannot |
345 | recurse into (everything else). |
433 | recurse into (everything else, including symlinks to directories). |
346 | |
434 | |
347 | C<aio_scandir> is a composite request that consists of many sub |
435 | C<aio_scandir> is a composite request that creates of many sub requests_ |
348 | requests. C<$maxreq> specifies the maximum number of outstanding aio |
436 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
349 | requests that this function generates. If it is C<< <= 0 >>, then a |
437 | this function generates. If it is C<< <= 0 >>, then a suitable default |
350 | suitable default will be chosen (currently 8). |
438 | will be chosen (currently 6). |
351 | |
439 | |
352 | On error, the callback is called without arguments, otherwise it receives |
440 | On error, the callback is called without arguments, otherwise it receives |
353 | two array-refs with path-relative entry names. |
441 | two array-refs with path-relative entry names. |
354 | |
442 | |
355 | Example: |
443 | Example: |
… | |
… | |
392 | =cut |
480 | =cut |
393 | |
481 | |
394 | sub aio_scandir($$$) { |
482 | sub aio_scandir($$$) { |
395 | my ($path, $maxreq, $cb) = @_; |
483 | my ($path, $maxreq, $cb) = @_; |
396 | |
484 | |
|
|
485 | my $grp = aio_group $cb; |
|
|
486 | |
397 | $maxreq = 8 if $maxreq <= 0; |
487 | $maxreq = 6 if $maxreq <= 0; |
398 | |
488 | |
399 | # stat once |
489 | # stat once |
400 | aio_stat $path, sub { |
490 | add $grp aio_stat $path, sub { |
401 | return $cb->() if $_[0]; |
491 | return $grp->result () if $_[0]; |
402 | my $now = time; |
492 | my $now = time; |
403 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
493 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
404 | |
494 | |
405 | # read the directory entries |
495 | # read the directory entries |
406 | aio_readdir $path, sub { |
496 | add $grp aio_readdir $path, sub { |
407 | my $entries = shift |
497 | my $entries = shift |
408 | or return $cb->(); |
498 | or return $grp->result (); |
409 | |
499 | |
410 | # stat the dir another time |
500 | # stat the dir another time |
411 | aio_stat $path, sub { |
501 | add $grp aio_stat $path, sub { |
412 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
502 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
413 | |
503 | |
414 | my $ndirs; |
504 | my $ndirs; |
415 | |
505 | |
416 | # take the slow route if anything looks fishy |
506 | # take the slow route if anything looks fishy |
… | |
… | |
418 | $ndirs = -1; |
508 | $ndirs = -1; |
419 | } else { |
509 | } else { |
420 | # if nlink == 2, we are finished |
510 | # if nlink == 2, we are finished |
421 | # on non-posix-fs's, we rely on nlink < 2 |
511 | # on non-posix-fs's, we rely on nlink < 2 |
422 | $ndirs = (stat _)[3] - 2 |
512 | $ndirs = (stat _)[3] - 2 |
423 | or return $cb->([], $entries); |
513 | or return $grp->result ([], $entries); |
424 | } |
514 | } |
425 | |
515 | |
426 | # sort into likely dirs and likely nondirs |
516 | # sort into likely dirs and likely nondirs |
427 | # dirs == files without ".", short entries first |
517 | # dirs == files without ".", short entries first |
428 | $entries = [map $_->[0], |
518 | $entries = [map $_->[0], |
… | |
… | |
430 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
520 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
431 | @$entries]; |
521 | @$entries]; |
432 | |
522 | |
433 | my (@dirs, @nondirs); |
523 | my (@dirs, @nondirs); |
434 | |
524 | |
435 | my ($statcb, $schedcb); |
525 | my $statgrp = add $grp aio_group sub { |
436 | my $nreq = 0; |
526 | $grp->result (\@dirs, \@nondirs); |
|
|
527 | }; |
437 | |
528 | |
438 | $schedcb = sub { |
529 | limit $statgrp $maxreq; |
439 | if (@$entries) { |
530 | feed $statgrp sub { |
440 | if ($nreq < $maxreq) { |
531 | return unless @$entries; |
441 | my $ent = pop @$entries; |
532 | my $entry = pop @$entries; |
|
|
533 | |
|
|
534 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
535 | if ($_[0] < 0) { |
|
|
536 | push @nondirs, $entry; |
|
|
537 | } else { |
|
|
538 | # need to check for real directory |
|
|
539 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
540 | if (-d _) { |
|
|
541 | push @dirs, $entry; |
|
|
542 | |
|
|
543 | unless (--$ndirs) { |
|
|
544 | push @nondirs, @$entries; |
|
|
545 | feed $statgrp; |
|
|
546 | } |
|
|
547 | } else { |
|
|
548 | push @nondirs, $entry; |
|
|
549 | } |
442 | $nreq++; |
550 | } |
443 | aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
|
|
444 | } |
551 | } |
445 | } elsif (!$nreq) { |
|
|
446 | # finished |
|
|
447 | undef $statcb; |
|
|
448 | undef $schedcb; |
|
|
449 | $cb->(\@dirs, \@nondirs) if $cb; |
|
|
450 | undef $cb; |
|
|
451 | } |
552 | }; |
452 | }; |
553 | }; |
453 | $statcb = sub { |
|
|
454 | my ($status, $entry) = @_; |
|
|
455 | |
|
|
456 | if ($status < 0) { |
|
|
457 | $nreq--; |
|
|
458 | push @nondirs, $entry; |
|
|
459 | &$schedcb; |
|
|
460 | } else { |
|
|
461 | # need to check for real directory |
|
|
462 | aio_lstat "$path/$entry", sub { |
|
|
463 | $nreq--; |
|
|
464 | |
|
|
465 | if (-d _) { |
|
|
466 | push @dirs, $entry; |
|
|
467 | |
|
|
468 | if (!--$ndirs) { |
|
|
469 | push @nondirs, @$entries; |
|
|
470 | $entries = []; |
|
|
471 | } |
|
|
472 | } else { |
|
|
473 | push @nondirs, $entry; |
|
|
474 | } |
|
|
475 | |
|
|
476 | &$schedcb; |
|
|
477 | } |
|
|
478 | } |
|
|
479 | }; |
|
|
480 | |
|
|
481 | &$schedcb while @$entries && $nreq < $maxreq; |
|
|
482 | }; |
554 | }; |
483 | }; |
555 | }; |
484 | }; |
556 | }; |
|
|
557 | |
|
|
558 | $grp |
485 | } |
559 | } |
486 | |
560 | |
487 | =item aio_fsync $fh, $callback->($status) |
561 | =item aio_fsync $fh, $callback->($status) |
488 | |
562 | |
489 | Asynchronously call fsync on the given filehandle and call the callback |
563 | Asynchronously call fsync on the given filehandle and call the callback |
… | |
… | |
495 | callback with the fdatasync result code. |
569 | callback with the fdatasync result code. |
496 | |
570 | |
497 | If this call isn't available because your OS lacks it or it couldn't be |
571 | 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. |
572 | detected, it will be emulated by calling C<fsync> instead. |
499 | |
573 | |
500 | =item aio_group $callback->() |
574 | =item aio_group $callback->(...) |
501 | |
575 | |
|
|
576 | This is a very special aio request: Instead of doing something, it is a |
|
|
577 | container for other aio requests, which is useful if you want to bundle |
|
|
578 | many requests into a single, composite, request with a definite callback |
|
|
579 | and the ability to cancel the whole request with its subrequests. |
|
|
580 | |
|
|
581 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
582 | for more info. |
|
|
583 | |
|
|
584 | Example: |
|
|
585 | |
|
|
586 | my $grp = aio_group sub { |
|
|
587 | print "all stats done\n"; |
|
|
588 | }; |
|
|
589 | |
|
|
590 | add $grp |
|
|
591 | (aio_stat ...), |
|
|
592 | (aio_stat ...), |
|
|
593 | ...; |
|
|
594 | |
|
|
595 | =item aio_nop $callback->() |
|
|
596 | |
|
|
597 | This is a special request - it does nothing in itself and is only used for |
|
|
598 | side effects, such as when you want to add a dummy request to a group so |
|
|
599 | that finishing the requests in the group depends on executing the given |
|
|
600 | code. |
|
|
601 | |
|
|
602 | While this request does nothing, it still goes through the execution |
|
|
603 | phase and still requires a worker thread. Thus, the callback will not |
|
|
604 | be executed immediately but only after other requests in the queue have |
|
|
605 | entered their execution phase. This can be used to measure request |
|
|
606 | latency. |
|
|
607 | |
502 | =item aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
608 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
503 | |
609 | |
504 | Mainly used for debugging and benchmarking, this aio request puts one of |
610 | Mainly used for debugging and benchmarking, this aio request puts one of |
505 | the request workers to sleep for the given time. |
611 | the request workers to sleep for the given time. |
506 | |
612 | |
|
|
613 | While it is theoretically handy to have simple I/O scheduling requests |
|
|
614 | like sleep and file handle readable/writable, the overhead this creates is |
|
|
615 | immense (it blocks a thread for a long time) so do not use this function |
|
|
616 | except to put your application under artificial I/O pressure. |
|
|
617 | |
507 | =back |
618 | =back |
508 | |
619 | |
509 | =head2 IO::AIO::REQ CLASS |
620 | =head2 IO::AIO::REQ CLASS |
510 | |
621 | |
511 | All non-aggregate C<aio_*> functions return an object of this class when |
622 | All non-aggregate C<aio_*> functions return an object of this class when |
512 | called in non-void context. |
623 | called in non-void context. |
513 | |
624 | |
514 | A request always moves through the following five states in its lifetime, |
|
|
515 | in order: B<ready> (request has been created, but has not been executed |
|
|
516 | yet), B<execute> (request is currently being executed), B<pending> |
|
|
517 | (request has been executed but callback has not been called yet), |
|
|
518 | B<result> (results are being processed synchronously, includes calling the |
|
|
519 | callback) and B<done> (request has reached the end of its lifetime and |
|
|
520 | holds no resources anymore). |
|
|
521 | |
|
|
522 | =over 4 |
625 | =over 4 |
523 | |
626 | |
524 | =item $req->cancel |
627 | =item cancel $req |
525 | |
628 | |
526 | Cancels the request, if possible. Has the effect of skipping execution |
629 | Cancels the request, if possible. Has the effect of skipping execution |
527 | when entering the B<execute> state and skipping calling the callback when |
630 | when entering the B<execute> state and skipping calling the callback when |
528 | entering the the B<result> state, but will leave the request otherwise |
631 | entering the the B<result> state, but will leave the request otherwise |
529 | untouched. That means that requests that currently execute will not be |
632 | untouched. That means that requests that currently execute will not be |
530 | stopped and resources held by the request will not be freed prematurely. |
633 | stopped and resources held by the request will not be freed prematurely. |
531 | |
634 | |
|
|
635 | =item cb $req $callback->(...) |
|
|
636 | |
|
|
637 | Replace (or simply set) the callback registered to the request. |
|
|
638 | |
|
|
639 | =back |
|
|
640 | |
|
|
641 | =head2 IO::AIO::GRP CLASS |
|
|
642 | |
|
|
643 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
644 | objects of this class, too. |
|
|
645 | |
|
|
646 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
647 | aio requests. |
|
|
648 | |
|
|
649 | You create one by calling the C<aio_group> constructing function with a |
|
|
650 | callback that will be called when all contained requests have entered the |
|
|
651 | C<done> state: |
|
|
652 | |
|
|
653 | my $grp = aio_group sub { |
|
|
654 | print "all requests are done\n"; |
|
|
655 | }; |
|
|
656 | |
|
|
657 | You add requests by calling the C<add> method with one or more |
|
|
658 | C<IO::AIO::REQ> objects: |
|
|
659 | |
|
|
660 | $grp->add (aio_unlink "..."); |
|
|
661 | |
|
|
662 | add $grp aio_stat "...", sub { |
|
|
663 | $_[0] or return $grp->result ("error"); |
|
|
664 | |
|
|
665 | # add another request dynamically, if first succeeded |
|
|
666 | add $grp aio_open "...", sub { |
|
|
667 | $grp->result ("ok"); |
|
|
668 | }; |
|
|
669 | }; |
|
|
670 | |
|
|
671 | This makes it very easy to create composite requests (see the source of |
|
|
672 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
673 | |
|
|
674 | =over 4 |
|
|
675 | |
|
|
676 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
677 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
678 | |
|
|
679 | =item * They can be canceled like any other request. Canceling will cancel not |
|
|
680 | only the request itself, but also all requests it contains. |
|
|
681 | |
|
|
682 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
683 | |
|
|
684 | =item * You must not add requests to a group from within the group callback (or |
|
|
685 | any later time). |
|
|
686 | |
|
|
687 | =back |
|
|
688 | |
|
|
689 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
690 | will finish very quickly. If they contain only requests that are in the |
|
|
691 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
692 | exist. |
|
|
693 | |
|
|
694 | That means after creating a group you have some time to add requests. And |
|
|
695 | in the callbacks of those requests, you can add further requests to the |
|
|
696 | group. And only when all those requests have finished will the the group |
|
|
697 | itself finish. |
|
|
698 | |
|
|
699 | =over 4 |
|
|
700 | |
|
|
701 | =item add $grp ... |
|
|
702 | |
|
|
703 | =item $grp->add (...) |
|
|
704 | |
|
|
705 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
|
|
706 | be added, including other groups, as long as you do not create circular |
|
|
707 | dependencies. |
|
|
708 | |
|
|
709 | Returns all its arguments. |
|
|
710 | |
|
|
711 | =item $grp->cancel_subs |
|
|
712 | |
|
|
713 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
714 | itself. Useful when you queued a lot of events but got a result early. |
|
|
715 | |
|
|
716 | =item $grp->result (...) |
|
|
717 | |
|
|
718 | Set the result value(s) that will be passed to the group callback when all |
|
|
719 | subrequests have finished. By default, no argument will be passed. |
|
|
720 | |
|
|
721 | =item feed $grp $callback->($grp) |
|
|
722 | |
|
|
723 | Sets a feeder/generator on this group: every group can have an attached |
|
|
724 | generator that generates requests if idle. The idea behind this is that, |
|
|
725 | although you could just queue as many requests as you want in a group, |
|
|
726 | this might starve other requests for a potentially long time. For |
|
|
727 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
|
|
728 | requests, delaying any later requests for a long time. |
|
|
729 | |
|
|
730 | To avoid this, and allow incremental generation of requests, you can |
|
|
731 | instead a group and set a feeder on it that generates those requests. The |
|
|
732 | feed callback will be called whenever there are few enough (see C<limit>, |
|
|
733 | below) requests active in the group itself and is expected to queue more |
|
|
734 | requests. |
|
|
735 | |
|
|
736 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
|
|
737 | not impose any limits). |
|
|
738 | |
|
|
739 | If the feed does not queue more requests when called, it will be |
|
|
740 | automatically removed from the group. |
|
|
741 | |
|
|
742 | If the feed limit is C<0>, it will be set to C<2> automatically. |
|
|
743 | |
|
|
744 | Example: |
|
|
745 | |
|
|
746 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
747 | |
|
|
748 | my $grp = aio_group sub { print "finished\n" }; |
|
|
749 | limit $grp 4; |
|
|
750 | feed $grp sub { |
|
|
751 | my $file = pop @files |
|
|
752 | or return; |
|
|
753 | |
|
|
754 | add $grp aio_stat $file, sub { ... }; |
|
|
755 | }; |
|
|
756 | |
|
|
757 | =item limit $grp $num |
|
|
758 | |
|
|
759 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
760 | the group contains less than this many requests. |
|
|
761 | |
|
|
762 | Setting the limit to C<0> will pause the feeding process. |
|
|
763 | |
532 | =back |
764 | =back |
533 | |
765 | |
534 | =head2 SUPPORT FUNCTIONS |
766 | =head2 SUPPORT FUNCTIONS |
535 | |
767 | |
536 | =over 4 |
768 | =over 4 |
… | |
… | |
548 | |
780 | |
549 | Process all outstanding events on the result pipe. You have to call this |
781 | Process all outstanding events on the result pipe. You have to call this |
550 | regularly. Returns the number of events processed. Returns immediately |
782 | regularly. Returns the number of events processed. Returns immediately |
551 | when no events are outstanding. |
783 | when no events are outstanding. |
552 | |
784 | |
|
|
785 | If not all requests were processed for whatever reason, the filehandle |
|
|
786 | will still be ready when C<poll_cb> returns. |
|
|
787 | |
553 | Example: Install an Event watcher that automatically calls |
788 | Example: Install an Event watcher that automatically calls |
554 | IO::AIO::poll_cb with high priority: |
789 | IO::AIO::poll_cb with high priority: |
555 | |
790 | |
556 | Event->io (fd => IO::AIO::poll_fileno, |
791 | Event->io (fd => IO::AIO::poll_fileno, |
557 | poll => 'r', async => 1, |
792 | poll => 'r', async => 1, |
558 | cb => \&IO::AIO::poll_cb); |
793 | cb => \&IO::AIO::poll_cb); |
559 | |
794 | |
|
|
795 | =item IO::AIO::poll_some $max_requests |
|
|
796 | |
|
|
797 | Similar to C<poll_cb>, but only processes up to C<$max_requests> requests |
|
|
798 | at a time. |
|
|
799 | |
|
|
800 | Useful if you want to ensure some level of interactiveness when perl is |
|
|
801 | not fast enough to process all requests in time. |
|
|
802 | |
|
|
803 | Example: Install an Event watcher that automatically calls |
|
|
804 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
|
|
805 | program get the CPU sometimes even under high AIO load. |
|
|
806 | |
|
|
807 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
808 | poll => 'r', nice => 1, |
|
|
809 | cb => sub { IO::AIO::poll_some 256 }); |
|
|
810 | |
560 | =item IO::AIO::poll_wait |
811 | =item IO::AIO::poll_wait |
561 | |
812 | |
562 | Wait till the result filehandle becomes ready for reading (simply does a |
813 | Wait till the result filehandle becomes ready for reading (simply does a |
563 | C<select> on the filehandle. This is useful if you want to synchronously wait |
814 | C<select> on the filehandle. This is useful if you want to synchronously wait |
564 | for some requests to finish). |
815 | for some requests to finish). |
… | |
… | |
593 | IO::AIO::poll_wait, IO::AIO::poll_cb |
844 | IO::AIO::poll_wait, IO::AIO::poll_cb |
594 | if IO::AIO::nreqs; |
845 | if IO::AIO::nreqs; |
595 | |
846 | |
596 | =item IO::AIO::min_parallel $nthreads |
847 | =item IO::AIO::min_parallel $nthreads |
597 | |
848 | |
598 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
849 | 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 |
850 | default is C<8>, which means eight asynchronous operations can execute |
600 | (the number of outstanding operations, however, is unlimited). |
851 | concurrently at any one time (the number of outstanding requests, |
|
|
852 | however, is unlimited). |
601 | |
853 | |
602 | IO::AIO starts threads only on demand, when an AIO request is queued and |
854 | IO::AIO starts threads only on demand, when an AIO request is queued and |
603 | no free thread exists. |
855 | no free thread exists. |
604 | |
856 | |
605 | It is recommended to keep the number of threads low, as some Linux |
857 | 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 |
858 | Linux kernel versions will scale negatively with the number of threads |
607 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
859 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
608 | threads should be fine. |
860 | versions, 4-32 threads should be fine. |
609 | |
861 | |
610 | Under most circumstances you don't need to call this function, as the |
862 | 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. |
863 | module selects a default that is suitable for low to moderate load. |
612 | |
864 | |
613 | =item IO::AIO::max_parallel $nthreads |
865 | =item IO::AIO::max_parallel $nthreads |
… | |
… | |
622 | This module automatically runs C<max_parallel 0> at program end, to ensure |
874 | This module automatically runs C<max_parallel 0> at program end, to ensure |
623 | that all threads are killed and that there are no outstanding requests. |
875 | that all threads are killed and that there are no outstanding requests. |
624 | |
876 | |
625 | Under normal circumstances you don't need to call this function. |
877 | Under normal circumstances you don't need to call this function. |
626 | |
878 | |
627 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
879 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
|
|
880 | |
|
|
881 | This is a very bad function to use in interactive programs because it |
|
|
882 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
883 | use an C<aio_group> together with a feed callback. |
628 | |
884 | |
629 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
885 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
630 | try to queue up more than this number of requests, the caller will block until |
886 | to queue up more than this number of requests, the next call to the |
631 | some requests have been handled. |
887 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
888 | function will block until the limit is no longer exceeded. |
632 | |
889 | |
633 | The default is very large, so normally there is no practical limit. If you |
890 | The default value is very large, so there is no practical limit on the |
634 | queue up many requests in a loop it often improves speed if you set |
891 | number of outstanding requests. |
635 | this to a relatively low number, such as C<100>. |
|
|
636 | |
892 | |
637 | Under normal circumstances you don't need to call this function. |
893 | You can still queue as many requests as you want. Therefore, |
|
|
894 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
|
|
895 | as a stop gap to shield against fatal memory overflow (with large values). |
638 | |
896 | |
639 | =back |
897 | =back |
640 | |
898 | |
641 | =cut |
899 | =cut |
642 | |
900 | |
… | |
… | |
654 | or return undef; |
912 | or return undef; |
655 | |
913 | |
656 | *$sym |
914 | *$sym |
657 | } |
915 | } |
658 | |
916 | |
659 | min_parallel 4; |
917 | min_parallel 8; |
660 | |
918 | |
661 | END { |
919 | END { |
662 | max_parallel 0; |
920 | max_parallel 0; |
663 | } |
921 | } |
664 | |
922 | |
… | |
… | |
669 | This module should do "the right thing" when the process using it forks: |
927 | This module should do "the right thing" when the process using it forks: |
670 | |
928 | |
671 | Before the fork, IO::AIO enters a quiescent state where no requests |
929 | Before the fork, IO::AIO enters a quiescent state where no requests |
672 | can be added in other threads and no results will be processed. After |
930 | can be added in other threads and no results will be processed. After |
673 | the fork the parent simply leaves the quiescent state and continues |
931 | the fork the parent simply leaves the quiescent state and continues |
674 | request/result processing, while the child clears the request/result |
932 | request/result processing, while the child frees the request/result queue |
675 | queue (so the requests started before the fork will only be handled in |
933 | (so that the requests started before the fork will only be handled in the |
676 | the parent). Threads will be started on demand until the limit ste in the |
934 | parent). Threads will be started on demand until the limit set in the |
677 | parent process has been reached again. |
935 | parent process has been reached again. |
678 | |
936 | |
679 | In short: the parent will, after a short pause, continue as if fork had |
937 | 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 |
938 | not been called, while the child will act as if IO::AIO has not been used |
681 | yet. |
939 | yet. |
682 | |
940 | |
|
|
941 | =head2 MEMORY USAGE |
|
|
942 | |
|
|
943 | Per-request usage: |
|
|
944 | |
|
|
945 | Each aio request uses - depending on your architecture - around 100-200 |
|
|
946 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
|
|
947 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
|
|
948 | scalars and other data passed into aio requests will also be locked and |
|
|
949 | will consume memory till the request has entered the done state. |
|
|
950 | |
|
|
951 | This is now awfully much, so queuing lots of requests is not usually a |
|
|
952 | problem. |
|
|
953 | |
|
|
954 | Per-thread usage: |
|
|
955 | |
|
|
956 | In the execution phase, some aio requests require more memory for |
|
|
957 | temporary buffers, and each thread requires a stack and other data |
|
|
958 | structures (usually around 16k-128k, depending on the OS). |
|
|
959 | |
|
|
960 | =head1 KNOWN BUGS |
|
|
961 | |
|
|
962 | Known bugs will be fixed in the next release. |
|
|
963 | |
683 | =head1 SEE ALSO |
964 | =head1 SEE ALSO |
684 | |
965 | |
685 | L<Coro>, L<Linux::AIO> (obsolete). |
966 | L<Coro::AIO>. |
686 | |
967 | |
687 | =head1 AUTHOR |
968 | =head1 AUTHOR |
688 | |
969 | |
689 | Marc Lehmann <schmorp@schmorp.de> |
970 | Marc Lehmann <schmorp@schmorp.de> |
690 | http://home.schmorp.de/ |
971 | http://home.schmorp.de/ |