… | |
… | |
14 | aio_unlink "/tmp/file", sub { }; |
14 | aio_unlink "/tmp/file", sub { }; |
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 | |
|
|
20 | use IO::AIO 2; # version has aio objects |
|
|
21 | |
|
|
22 | my $req = aio_unlink "/tmp/file", sub { }; |
|
|
23 | $req->cancel; # cancel request if still in queue |
|
|
24 | |
|
|
25 | # AnyEvent |
|
|
26 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
|
|
27 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
19 | |
28 | |
20 | # Event |
29 | # Event |
21 | Event->io (fd => IO::AIO::poll_fileno, |
30 | Event->io (fd => IO::AIO::poll_fileno, |
22 | poll => 'r', |
31 | poll => 'r', |
23 | cb => \&IO::AIO::poll_cb); |
32 | cb => \&IO::AIO::poll_cb); |
… | |
… | |
57 | =cut |
66 | =cut |
58 | |
67 | |
59 | package IO::AIO; |
68 | package IO::AIO; |
60 | |
69 | |
61 | no warnings; |
70 | no warnings; |
|
|
71 | use strict 'vars'; |
62 | |
72 | |
63 | use base 'Exporter'; |
73 | use base 'Exporter'; |
64 | |
74 | |
65 | use Fcntl (); |
|
|
66 | |
|
|
67 | BEGIN { |
75 | BEGIN { |
68 | $VERSION = 1.2; |
76 | our $VERSION = '2.0'; |
69 | |
77 | |
70 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
78 | our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
71 | aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead); |
79 | 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 |
|
|
81 | aio_group); |
72 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
82 | our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
|
|
83 | |
|
|
84 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
73 | |
85 | |
74 | require XSLoader; |
86 | require XSLoader; |
75 | XSLoader::load IO::AIO, $VERSION; |
87 | XSLoader::load ("IO::AIO", $VERSION); |
76 | } |
88 | } |
77 | |
89 | |
78 | =head1 FUNCTIONS |
90 | =head1 FUNCTIONS |
79 | |
91 | |
80 | =head2 AIO FUNCTIONS |
92 | =head2 AIO FUNCTIONS |
… | |
… | |
88 | syscall has been executed asynchronously. |
100 | syscall has been executed asynchronously. |
89 | |
101 | |
90 | All functions expecting a filehandle keep a copy of the filehandle |
102 | All functions expecting a filehandle keep a copy of the filehandle |
91 | internally until the request has finished. |
103 | internally until the request has finished. |
92 | |
104 | |
|
|
105 | All requests return objects of type L<IO::AIO::REQ> that allow further |
|
|
106 | manipulation of those requests while they are in-flight. |
|
|
107 | |
93 | The pathnames you pass to these routines I<must> be absolute and |
108 | The pathnames you pass to these routines I<must> be absolute and |
94 | encoded in byte form. The reason for the former is that at the time the |
109 | encoded in byte form. The reason for the former is that at the time the |
95 | request is being executed, the current working directory could have |
110 | request is being executed, the current working directory could have |
96 | changed. Alternatively, you can make sure that you never change the |
111 | changed. Alternatively, you can make sure that you never change the |
97 | current working directory. |
112 | current working directory. |
… | |
… | |
103 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
118 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
104 | use something else. |
119 | use something else. |
105 | |
120 | |
106 | =over 4 |
121 | =over 4 |
107 | |
122 | |
108 | =item aio_open $pathname, $flags, $mode, $callback |
123 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
109 | |
124 | |
110 | Asynchronously open or create a file and call the callback with a newly |
125 | Asynchronously open or create a file and call the callback with a newly |
111 | created filehandle for the file. |
126 | created filehandle for the file. |
112 | |
127 | |
113 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
128 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
… | |
… | |
130 | } else { |
145 | } else { |
131 | die "open failed: $!\n"; |
146 | die "open failed: $!\n"; |
132 | } |
147 | } |
133 | }; |
148 | }; |
134 | |
149 | |
135 | =item aio_close $fh, $callback |
150 | =item aio_close $fh, $callback->($status) |
136 | |
151 | |
137 | Asynchronously close a file and call the callback with the result |
152 | Asynchronously close a file and call the callback with the result |
138 | code. I<WARNING:> although accepted, you should not pass in a perl |
153 | code. I<WARNING:> although accepted, you should not pass in a perl |
139 | filehandle here, as perl will likely close the file descriptor another |
154 | filehandle here, as perl will likely close the file descriptor another |
140 | time when the filehandle is destroyed. Normally, you can safely call perls |
155 | time when the filehandle is destroyed. Normally, you can safely call perls |
141 | C<close> or just let filehandles go out of scope. |
156 | C<close> or just let filehandles go out of scope. |
142 | |
157 | |
143 | This is supposed to be a bug in the API, so that might change. It's |
158 | This is supposed to be a bug in the API, so that might change. It's |
144 | therefore best to avoid this function. |
159 | therefore best to avoid this function. |
145 | |
160 | |
146 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
161 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
147 | |
162 | |
148 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
163 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
149 | |
164 | |
150 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
165 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
151 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
166 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
152 | callback without the actual number of bytes read (or -1 on error, just |
167 | callback without the actual number of bytes read (or -1 on error, just |
153 | like the syscall). |
168 | like the syscall). |
154 | |
169 | |
|
|
170 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
|
|
171 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
|
|
172 | necessary/optional hardware is installed). |
|
|
173 | |
155 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
174 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
156 | offset C<0> within the scalar: |
175 | offset C<0> within the scalar: |
157 | |
176 | |
158 | aio_read $fh, 7, 15, $buffer, 0, sub { |
177 | aio_read $fh, 7, 15, $buffer, 0, sub { |
159 | $_[0] > 0 or die "read error: $!"; |
178 | $_[0] > 0 or die "read error: $!"; |
160 | print "read $_[0] bytes: <$buffer>\n"; |
179 | print "read $_[0] bytes: <$buffer>\n"; |
161 | }; |
180 | }; |
162 | |
181 | |
|
|
182 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
183 | |
|
|
184 | Try to move the I<file> (directories not supported as either source or |
|
|
185 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
186 | the C<0> (error) or C<-1> ok. |
|
|
187 | |
|
|
188 | This is a composite request that tries to rename(2) the file first. If |
|
|
189 | rename files with C<EXDEV>, it creates the destination file with mode 0200 |
|
|
190 | and copies the contents of the source file into it using C<aio_sendfile>, |
|
|
191 | followed by restoring atime, mtime, access mode and uid/gid, in that |
|
|
192 | order, and unlinking the C<$srcpath>. |
|
|
193 | |
|
|
194 | If an error occurs, the partial destination file will be unlinked, if |
|
|
195 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
196 | errors are being ignored. |
|
|
197 | |
|
|
198 | =cut |
|
|
199 | |
|
|
200 | sub aio_move($$$) { |
|
|
201 | my ($src, $dst, $cb) = @_; |
|
|
202 | |
|
|
203 | my $grp = aio_group; |
|
|
204 | |
|
|
205 | add $grp aio_rename $src, $dst, sub { |
|
|
206 | if ($_[0] && $! == EXDEV) { |
|
|
207 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
208 | if (my $src_fh = $_[0]) { |
|
|
209 | my @stat = stat $src_fh; |
|
|
210 | |
|
|
211 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
|
|
212 | if (my $dst_fh = $_[0]) { |
|
|
213 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
214 | close $src_fh; |
|
|
215 | |
|
|
216 | if ($_[0] == $stat[7]) { |
|
|
217 | utime $stat[8], $stat[9], $dst; |
|
|
218 | chmod $stat[2] & 07777, $dst_fh; |
|
|
219 | chown $stat[4], $stat[5], $dst_fh; |
|
|
220 | close $dst_fh; |
|
|
221 | |
|
|
222 | add $grp aio_unlink $src, sub { |
|
|
223 | $cb->($_[0]); |
|
|
224 | }; |
|
|
225 | } else { |
|
|
226 | my $errno = $!; |
|
|
227 | add $grp aio_unlink $dst, sub { |
|
|
228 | $! = $errno; |
|
|
229 | $cb->(-1); |
|
|
230 | }; |
|
|
231 | } |
|
|
232 | }; |
|
|
233 | } else { |
|
|
234 | $cb->(-1); |
|
|
235 | } |
|
|
236 | }, |
|
|
237 | |
|
|
238 | } else { |
|
|
239 | $cb->(-1); |
|
|
240 | } |
|
|
241 | }; |
|
|
242 | } else { |
|
|
243 | $cb->($_[0]); |
|
|
244 | } |
|
|
245 | }; |
|
|
246 | |
|
|
247 | $grp |
|
|
248 | } |
|
|
249 | |
|
|
250 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
|
|
251 | |
|
|
252 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
|
|
253 | reading at byte offset C<$in_offset>, and starts writing at the current |
|
|
254 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
|
|
255 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
|
|
256 | other. |
|
|
257 | |
|
|
258 | This call tries to make use of a native C<sendfile> syscall to provide |
|
|
259 | zero-copy operation. For this to work, C<$out_fh> should refer to a |
|
|
260 | socket, and C<$in_fh> should refer to mmap'able file. |
|
|
261 | |
|
|
262 | If the native sendfile call fails or is not implemented, it will be |
|
|
263 | emulated, so you can call C<aio_sendfile> on any type of filehandle |
|
|
264 | regardless of the limitations of the operating system. |
|
|
265 | |
|
|
266 | Please note, however, that C<aio_sendfile> can read more bytes from |
|
|
267 | C<$in_fh> than are written, and there is no way to find out how many |
|
|
268 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
|
|
269 | provides the number of bytes written to C<$out_fh>. Only if the result |
|
|
270 | value equals C<$length> one can assume that C<$length> bytes have been |
|
|
271 | read. |
|
|
272 | |
163 | =item aio_readahead $fh,$offset,$length, $callback |
273 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
164 | |
274 | |
165 | C<aio_readahead> populates the page cache with data from a file so that |
275 | C<aio_readahead> populates the page cache with data from a file so that |
166 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
276 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
167 | argument specifies the starting point from which data is to be read and |
277 | argument specifies the starting point from which data is to be read and |
168 | C<$length> specifies the number of bytes to be read. I/O is performed in |
278 | C<$length> specifies the number of bytes to be read. I/O is performed in |
… | |
… | |
172 | file. The current file offset of the file is left unchanged. |
282 | file. The current file offset of the file is left unchanged. |
173 | |
283 | |
174 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
284 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
175 | emulated by simply reading the data, which would have a similar effect. |
285 | emulated by simply reading the data, which would have a similar effect. |
176 | |
286 | |
177 | =item aio_stat $fh_or_path, $callback |
287 | =item aio_stat $fh_or_path, $callback->($status) |
178 | |
288 | |
179 | =item aio_lstat $fh, $callback |
289 | =item aio_lstat $fh, $callback->($status) |
180 | |
290 | |
181 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
291 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
182 | be called after the stat and the results will be available using C<stat _> |
292 | be called after the stat and the results will be available using C<stat _> |
183 | or C<-s _> etc... |
293 | or C<-s _> etc... |
184 | |
294 | |
… | |
… | |
194 | aio_stat "/etc/passwd", sub { |
304 | aio_stat "/etc/passwd", sub { |
195 | $_[0] and die "stat failed: $!"; |
305 | $_[0] and die "stat failed: $!"; |
196 | print "size is ", -s _, "\n"; |
306 | print "size is ", -s _, "\n"; |
197 | }; |
307 | }; |
198 | |
308 | |
199 | =item aio_unlink $pathname, $callback |
309 | =item aio_unlink $pathname, $callback->($status) |
200 | |
310 | |
201 | Asynchronously unlink (delete) a file and call the callback with the |
311 | Asynchronously unlink (delete) a file and call the callback with the |
202 | result code. |
312 | result code. |
203 | |
313 | |
|
|
314 | =item aio_link $srcpath, $dstpath, $callback->($status) |
|
|
315 | |
|
|
316 | Asynchronously create a new link to the existing object at C<$srcpath> at |
|
|
317 | the path C<$dstpath> and call the callback with the result code. |
|
|
318 | |
|
|
319 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
320 | |
|
|
321 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
|
|
322 | the path C<$dstpath> and call the callback with the result code. |
|
|
323 | |
|
|
324 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
325 | |
|
|
326 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
|
|
327 | rename(2) and call the callback with the result code. |
|
|
328 | |
204 | =item aio_rmdir $pathname, $callback |
329 | =item aio_rmdir $pathname, $callback->($status) |
205 | |
330 | |
206 | Asynchronously rmdir (delete) a directory and call the callback with the |
331 | Asynchronously rmdir (delete) a directory and call the callback with the |
207 | result code. |
332 | result code. |
208 | |
333 | |
|
|
334 | =item aio_readdir $pathname, $callback->($entries) |
|
|
335 | |
|
|
336 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
|
|
337 | directory (i.e. opendir + readdir + closedir). The entries will not be |
|
|
338 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
|
|
339 | |
|
|
340 | The callback a single argument which is either C<undef> or an array-ref |
|
|
341 | with the filenames. |
|
|
342 | |
|
|
343 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
|
|
344 | |
|
|
345 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
|
|
346 | separate the entries of directory C<$path> into two sets of names, ones |
|
|
347 | you can recurse into (directories or links to them), and ones you cannot |
|
|
348 | recurse into (everything else). |
|
|
349 | |
|
|
350 | C<aio_scandir> is a composite request that consists of many sub |
|
|
351 | requests. C<$maxreq> specifies the maximum number of outstanding aio |
|
|
352 | requests that this function generates. If it is C<< <= 0 >>, then a |
|
|
353 | suitable default will be chosen (currently 8). |
|
|
354 | |
|
|
355 | On error, the callback is called without arguments, otherwise it receives |
|
|
356 | two array-refs with path-relative entry names. |
|
|
357 | |
|
|
358 | Example: |
|
|
359 | |
|
|
360 | aio_scandir $dir, 0, sub { |
|
|
361 | my ($dirs, $nondirs) = @_; |
|
|
362 | print "real directories: @$dirs\n"; |
|
|
363 | print "everything else: @$nondirs\n"; |
|
|
364 | }; |
|
|
365 | |
|
|
366 | Implementation notes. |
|
|
367 | |
|
|
368 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
|
|
369 | |
|
|
370 | After reading the directory, the modification time, size etc. of the |
|
|
371 | directory before and after the readdir is checked, and if they match (and |
|
|
372 | isn't the current time), the link count will be used to decide how many |
|
|
373 | entries are directories (if >= 2). Otherwise, no knowledge of the number |
|
|
374 | of subdirectories will be assumed. |
|
|
375 | |
|
|
376 | Then entries will be sorted into likely directories (everything without |
|
|
377 | a non-initial dot currently) and likely non-directories (everything |
|
|
378 | else). Then every entry plus an appended C</.> will be C<stat>'ed, |
|
|
379 | likely directories first. If that succeeds, it assumes that the entry |
|
|
380 | is a directory or a symlink to directory (which will be checked |
|
|
381 | seperately). This is often faster than stat'ing the entry itself because |
|
|
382 | filesystems might detect the type of the entry without reading the inode |
|
|
383 | data (e.g. ext2fs filetype feature). |
|
|
384 | |
|
|
385 | If the known number of directories (link count - 2) has been reached, the |
|
|
386 | rest of the entries is assumed to be non-directories. |
|
|
387 | |
|
|
388 | This only works with certainty on POSIX (= UNIX) filesystems, which |
|
|
389 | fortunately are the vast majority of filesystems around. |
|
|
390 | |
|
|
391 | It will also likely work on non-POSIX filesystems with reduced efficiency |
|
|
392 | as those tend to return 0 or 1 as link counts, which disables the |
|
|
393 | directory counting heuristic. |
|
|
394 | |
|
|
395 | =cut |
|
|
396 | |
|
|
397 | sub aio_scandir($$$) { |
|
|
398 | my ($path, $maxreq, $cb) = @_; |
|
|
399 | |
|
|
400 | my $grp = aio_group; |
|
|
401 | |
|
|
402 | $maxreq = 8 if $maxreq <= 0; |
|
|
403 | |
|
|
404 | # stat once |
|
|
405 | add $grp aio_stat $path, sub { |
|
|
406 | return $cb->() if $_[0]; |
|
|
407 | my $now = time; |
|
|
408 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
409 | |
|
|
410 | # read the directory entries |
|
|
411 | add $grp aio_readdir $path, sub { |
|
|
412 | my $entries = shift |
|
|
413 | or return $cb->(); |
|
|
414 | |
|
|
415 | # stat the dir another time |
|
|
416 | add $grp aio_stat $path, sub { |
|
|
417 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
|
|
418 | |
|
|
419 | my $ndirs; |
|
|
420 | |
|
|
421 | # take the slow route if anything looks fishy |
|
|
422 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
|
|
423 | $ndirs = -1; |
|
|
424 | } else { |
|
|
425 | # if nlink == 2, we are finished |
|
|
426 | # on non-posix-fs's, we rely on nlink < 2 |
|
|
427 | $ndirs = (stat _)[3] - 2 |
|
|
428 | or return $cb->([], $entries); |
|
|
429 | } |
|
|
430 | |
|
|
431 | # sort into likely dirs and likely nondirs |
|
|
432 | # dirs == files without ".", short entries first |
|
|
433 | $entries = [map $_->[0], |
|
|
434 | sort { $b->[1] cmp $a->[1] } |
|
|
435 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
|
|
436 | @$entries]; |
|
|
437 | |
|
|
438 | my (@dirs, @nondirs); |
|
|
439 | |
|
|
440 | my ($statcb, $schedcb); |
|
|
441 | my $nreq = 0; |
|
|
442 | |
|
|
443 | $schedcb = sub { |
|
|
444 | if (@$entries) { |
|
|
445 | if ($nreq < $maxreq) { |
|
|
446 | my $ent = pop @$entries; |
|
|
447 | $nreq++; |
|
|
448 | add $grp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
|
|
449 | } |
|
|
450 | } elsif (!$nreq) { |
|
|
451 | # finished |
|
|
452 | undef $statcb; |
|
|
453 | undef $schedcb; |
|
|
454 | $cb->(\@dirs, \@nondirs) if $cb; |
|
|
455 | undef $cb; |
|
|
456 | } |
|
|
457 | }; |
|
|
458 | $statcb = sub { |
|
|
459 | my ($status, $entry) = @_; |
|
|
460 | |
|
|
461 | if ($status < 0) { |
|
|
462 | $nreq--; |
|
|
463 | push @nondirs, $entry; |
|
|
464 | &$schedcb; |
|
|
465 | } else { |
|
|
466 | # need to check for real directory |
|
|
467 | add $grp aio_lstat "$path/$entry", sub { |
|
|
468 | $nreq--; |
|
|
469 | |
|
|
470 | if (-d _) { |
|
|
471 | push @dirs, $entry; |
|
|
472 | |
|
|
473 | if (!--$ndirs) { |
|
|
474 | push @nondirs, @$entries; |
|
|
475 | $entries = []; |
|
|
476 | } |
|
|
477 | } else { |
|
|
478 | push @nondirs, $entry; |
|
|
479 | } |
|
|
480 | |
|
|
481 | &$schedcb; |
|
|
482 | } |
|
|
483 | } |
|
|
484 | }; |
|
|
485 | |
|
|
486 | &$schedcb while @$entries && $nreq < $maxreq; |
|
|
487 | }; |
|
|
488 | }; |
|
|
489 | }; |
|
|
490 | |
|
|
491 | $grp |
|
|
492 | } |
|
|
493 | |
209 | =item aio_fsync $fh, $callback |
494 | =item aio_fsync $fh, $callback->($status) |
210 | |
495 | |
211 | Asynchronously call fsync on the given filehandle and call the callback |
496 | Asynchronously call fsync on the given filehandle and call the callback |
212 | with the fsync result code. |
497 | with the fsync result code. |
213 | |
498 | |
214 | =item aio_fdatasync $fh, $callback |
499 | =item aio_fdatasync $fh, $callback->($status) |
215 | |
500 | |
216 | Asynchronously call fdatasync on the given filehandle and call the |
501 | Asynchronously call fdatasync on the given filehandle and call the |
217 | callback with the fdatasync result code. |
502 | callback with the fdatasync result code. |
218 | |
503 | |
219 | If this call isn't available because your OS lacks it or it couldn't be |
504 | If this call isn't available because your OS lacks it or it couldn't be |
220 | detected, it will be emulated by calling C<fsync> instead. |
505 | detected, it will be emulated by calling C<fsync> instead. |
|
|
506 | |
|
|
507 | =item aio_group $callback->() |
|
|
508 | |
|
|
509 | [EXPERIMENTAL] |
|
|
510 | |
|
|
511 | This is a very special aio request: Instead of doing something, it is a |
|
|
512 | container for other aio requests, which is useful if you want to bundle |
|
|
513 | many requests into a single, composite, request. |
|
|
514 | |
|
|
515 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
516 | for more info. |
|
|
517 | |
|
|
518 | Example: |
|
|
519 | |
|
|
520 | my $grp = aio_group sub { |
|
|
521 | print "all stats done\n"; |
|
|
522 | }; |
|
|
523 | |
|
|
524 | add $grp |
|
|
525 | (aio_stat ...), |
|
|
526 | (aio_stat ...), |
|
|
527 | ...; |
|
|
528 | |
|
|
529 | =item aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
|
|
530 | |
|
|
531 | Mainly used for debugging and benchmarking, this aio request puts one of |
|
|
532 | the request workers to sleep for the given time. |
|
|
533 | |
|
|
534 | =back |
|
|
535 | |
|
|
536 | =head2 IO::AIO::REQ CLASS |
|
|
537 | |
|
|
538 | All non-aggregate C<aio_*> functions return an object of this class when |
|
|
539 | called in non-void context. |
|
|
540 | |
|
|
541 | A request always moves through the following five states in its lifetime, |
|
|
542 | in order: B<ready> (request has been created, but has not been executed |
|
|
543 | yet), B<execute> (request is currently being executed), B<pending> |
|
|
544 | (request has been executed but callback has not been called yet), |
|
|
545 | B<result> (results are being processed synchronously, includes calling the |
|
|
546 | callback) and B<done> (request has reached the end of its lifetime and |
|
|
547 | holds no resources anymore). |
|
|
548 | |
|
|
549 | =over 4 |
|
|
550 | |
|
|
551 | =item $req->cancel |
|
|
552 | |
|
|
553 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
554 | when entering the B<execute> state and skipping calling the callback when |
|
|
555 | entering the the B<result> state, but will leave the request otherwise |
|
|
556 | untouched. That means that requests that currently execute will not be |
|
|
557 | stopped and resources held by the request will not be freed prematurely. |
|
|
558 | |
|
|
559 | =back |
|
|
560 | |
|
|
561 | =head2 IO::AIO::GRP CLASS |
|
|
562 | |
|
|
563 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
564 | objects of this class, too. |
|
|
565 | |
|
|
566 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
567 | aio requests. |
|
|
568 | |
|
|
569 | You create one by calling the C<aio_group> constructing function with a |
|
|
570 | callback that will be called when all contained requests have entered the |
|
|
571 | C<done> state: |
|
|
572 | |
|
|
573 | my $grp = aio_group sub { |
|
|
574 | print "all requests are done\n"; |
|
|
575 | }; |
|
|
576 | |
|
|
577 | You add requests by calling the C<add> method with one or more |
|
|
578 | C<IO::AIO::REQ> objects: |
|
|
579 | |
|
|
580 | $grp->add (aio_unlink "..."); |
|
|
581 | |
|
|
582 | add $grp aio_stat "...", sub { ... }; |
|
|
583 | |
|
|
584 | This makes it very easy to create composite requests (see the source of |
|
|
585 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
586 | |
|
|
587 | The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
588 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
589 | |
|
|
590 | They can be canceled like any other request. Canceling will cancel not |
|
|
591 | just the request itself, but also all requests it contains. |
|
|
592 | |
|
|
593 | They can also can also be added to other IO::AIO::GRP objects. |
|
|
594 | |
|
|
595 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
596 | will finish very quickly. If they contain only requests that are in the |
|
|
597 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
598 | exist. |
|
|
599 | |
|
|
600 | =over 4 |
|
|
601 | |
|
|
602 | =item $grp->add (...) |
|
|
603 | |
|
|
604 | =item add $grp ... |
|
|
605 | |
|
|
606 | Add one or more |
|
|
607 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
608 | when entering the B<execute> state and skipping calling the callback when |
|
|
609 | entering the the B<result> state, but will leave the request otherwise |
|
|
610 | untouched. That means that requests that currently execute will not be |
|
|
611 | stopped and resources held by the request will not be freed prematurely. |
221 | |
612 | |
222 | =back |
613 | =back |
223 | |
614 | |
224 | =head2 SUPPORT FUNCTIONS |
615 | =head2 SUPPORT FUNCTIONS |
225 | |
616 | |
… | |
… | |
283 | IO::AIO::poll_wait, IO::AIO::poll_cb |
674 | IO::AIO::poll_wait, IO::AIO::poll_cb |
284 | if IO::AIO::nreqs; |
675 | if IO::AIO::nreqs; |
285 | |
676 | |
286 | =item IO::AIO::min_parallel $nthreads |
677 | =item IO::AIO::min_parallel $nthreads |
287 | |
678 | |
288 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
679 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
289 | C<1>, which means a single asynchronous operation can be done at one time |
680 | is C<4>, which means four asynchronous operations can be done at one time |
290 | (the number of outstanding operations, however, is unlimited). |
681 | (the number of outstanding operations, however, is unlimited). |
|
|
682 | |
|
|
683 | IO::AIO starts threads only on demand, when an AIO request is queued and |
|
|
684 | no free thread exists. |
291 | |
685 | |
292 | It is recommended to keep the number of threads low, as some Linux |
686 | It is recommended to keep the number of threads low, as some Linux |
293 | kernel versions will scale negatively with the number of threads (higher |
687 | kernel versions will scale negatively with the number of threads (higher |
294 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
688 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
295 | threads should be fine. |
689 | threads should be fine. |
296 | |
690 | |
297 | Under normal circumstances you don't need to call this function, as this |
691 | Under most circumstances you don't need to call this function, as the |
298 | module automatically starts some threads (the exact number might change, |
692 | module selects a default that is suitable for low to moderate load. |
299 | and is currently 4). |
|
|
300 | |
693 | |
301 | =item IO::AIO::max_parallel $nthreads |
694 | =item IO::AIO::max_parallel $nthreads |
302 | |
695 | |
303 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
696 | Sets the maximum number of AIO threads to C<$nthreads>. If more than the |
304 | the specified number of threads are currently running, kill them. This |
697 | specified number of threads are currently running, this function kills |
305 | function blocks until the limit is reached. |
698 | them. This function blocks until the limit is reached. |
|
|
699 | |
|
|
700 | While C<$nthreads> are zero, aio requests get queued but not executed |
|
|
701 | until the number of threads has been increased again. |
306 | |
702 | |
307 | This module automatically runs C<max_parallel 0> at program end, to ensure |
703 | This module automatically runs C<max_parallel 0> at program end, to ensure |
308 | that all threads are killed and that there are no outstanding requests. |
704 | that all threads are killed and that there are no outstanding requests. |
309 | |
705 | |
310 | Under normal circumstances you don't need to call this function. |
706 | Under normal circumstances you don't need to call this function. |
… | |
… | |
314 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
710 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
315 | try to queue up more than this number of requests, the caller will block until |
711 | try to queue up more than this number of requests, the caller will block until |
316 | some requests have been handled. |
712 | some requests have been handled. |
317 | |
713 | |
318 | The default is very large, so normally there is no practical limit. If you |
714 | The default is very large, so normally there is no practical limit. If you |
319 | queue up many requests in a loop it it often improves speed if you set |
715 | queue up many requests in a loop it often improves speed if you set |
320 | this to a relatively low number, such as C<100>. |
716 | this to a relatively low number, such as C<100>. |
321 | |
717 | |
322 | Under normal circumstances you don't need to call this function. |
718 | Under normal circumstances you don't need to call this function. |
323 | |
719 | |
324 | =back |
720 | =back |
… | |
… | |
349 | |
745 | |
350 | 1; |
746 | 1; |
351 | |
747 | |
352 | =head2 FORK BEHAVIOUR |
748 | =head2 FORK BEHAVIOUR |
353 | |
749 | |
354 | Before the fork IO::AIO first handles all outstanding requests - if other |
750 | This module should do "the right thing" when the process using it forks: |
355 | threads add requests during this period, this time is prolonged. It then |
751 | |
356 | enters a quiescent state where no requests can be added in other threads |
752 | Before the fork, IO::AIO enters a quiescent state where no requests |
357 | and no results will be processed. After the fork the parent simply leaves |
753 | can be added in other threads and no results will be processed. After |
358 | the quiescent state and continues request processing, while the child |
754 | the fork the parent simply leaves the quiescent state and continues |
359 | starts the same number of threads as were in use by the parent. |
755 | request/result processing, while the child clears the request/result |
|
|
756 | queue (so the requests started before the fork will only be handled in |
|
|
757 | the parent). Threads will be started on demand until the limit ste in the |
|
|
758 | parent process has been reached again. |
|
|
759 | |
|
|
760 | In short: the parent will, after a short pause, continue as if fork had |
|
|
761 | not been called, while the child will act as if IO::AIO has not been used |
|
|
762 | yet. |
360 | |
763 | |
361 | =head1 SEE ALSO |
764 | =head1 SEE ALSO |
362 | |
765 | |
363 | L<Coro>, L<Linux::AIO>. |
766 | L<Coro>, L<Linux::AIO> (obsolete). |
364 | |
767 | |
365 | =head1 AUTHOR |
768 | =head1 AUTHOR |
366 | |
769 | |
367 | Marc Lehmann <schmorp@schmorp.de> |
770 | Marc Lehmann <schmorp@schmorp.de> |
368 | http://home.schmorp.de/ |
771 | http://home.schmorp.de/ |