… | |
… | |
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 | # Event |
20 | # version 2+ has request and group objects |
|
|
21 | use IO::AIO 2; |
|
|
22 | |
|
|
23 | aioreq_pri 4; # give next request a very high priority |
|
|
24 | my $req = aio_unlink "/tmp/file", sub { }; |
|
|
25 | $req->cancel; # cancel request if still in queue |
|
|
26 | |
|
|
27 | my $grp = aio_group sub { print "all stats done\n" }; |
|
|
28 | add $grp aio_stat "..." for ...; |
|
|
29 | |
|
|
30 | # AnyEvent integration |
|
|
31 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
|
|
32 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
|
|
33 | |
|
|
34 | # Event integration |
21 | Event->io (fd => IO::AIO::poll_fileno, |
35 | Event->io (fd => IO::AIO::poll_fileno, |
22 | poll => 'r', |
36 | poll => 'r', |
23 | cb => \&IO::AIO::poll_cb); |
37 | cb => \&IO::AIO::poll_cb); |
24 | |
38 | |
25 | # Glib/Gtk2 |
39 | # Glib/Gtk2 integration |
26 | add_watch Glib::IO IO::AIO::poll_fileno, |
40 | add_watch Glib::IO IO::AIO::poll_fileno, |
27 | in => sub { IO::AIO::poll_cb; 1 }; |
41 | in => sub { IO::AIO::poll_cb; 1 }; |
28 | |
42 | |
29 | # Tk |
43 | # Tk integration |
30 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
44 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
31 | readable => \&IO::AIO::poll_cb); |
45 | readable => \&IO::AIO::poll_cb); |
32 | |
46 | |
33 | # Danga::Socket |
47 | # Danga::Socket integration |
34 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
48 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
35 | \&IO::AIO::poll_cb); |
49 | \&IO::AIO::poll_cb); |
36 | |
50 | |
37 | |
|
|
38 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
39 | |
52 | |
40 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
41 | operating system supports. |
54 | operating system supports. |
42 | |
55 | |
43 | 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 |
44 | 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 |
45 | 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 |
46 | 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 |
47 | aio functions available on many operating systems. However, they are often |
60 | functions available on many operating systems. However, they are often |
48 | 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 |
49 | 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 |
50 | 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. |
51 | |
65 | |
52 | 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-) |
53 | currently not reentrant, so use appropriate locking yourself, always call |
67 | threads, it is currently not reentrant in any way, so use appropriate |
54 | 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 |
55 | 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). |
56 | |
120 | |
57 | =cut |
121 | =cut |
58 | |
122 | |
59 | package IO::AIO; |
123 | package IO::AIO; |
60 | |
124 | |
61 | no warnings; |
125 | no warnings; |
|
|
126 | use strict 'vars'; |
62 | |
127 | |
63 | use base 'Exporter'; |
128 | use base 'Exporter'; |
64 | |
129 | |
65 | use Fcntl (); |
|
|
66 | |
|
|
67 | BEGIN { |
130 | BEGIN { |
68 | $VERSION = 1.6; |
131 | our $VERSION = '2.0'; |
69 | |
132 | |
70 | @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 |
71 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_symlink |
134 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
72 | aio_fsync aio_fdatasync aio_readahead); |
135 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
73 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel |
136 | aio_group aio_nop); |
74 | 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 max_outstanding nreqs); |
|
|
140 | |
|
|
141 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
75 | |
142 | |
76 | require XSLoader; |
143 | require XSLoader; |
77 | XSLoader::load IO::AIO, $VERSION; |
144 | XSLoader::load ("IO::AIO", $VERSION); |
78 | } |
145 | } |
79 | |
146 | |
80 | =head1 FUNCTIONS |
147 | =head1 FUNCTIONS |
81 | |
148 | |
82 | =head2 AIO FUNCTIONS |
149 | =head2 AIO FUNCTIONS |
… | |
… | |
90 | syscall has been executed asynchronously. |
157 | syscall has been executed asynchronously. |
91 | |
158 | |
92 | All functions expecting a filehandle keep a copy of the filehandle |
159 | All functions expecting a filehandle keep a copy of the filehandle |
93 | internally until the request has finished. |
160 | internally until the request has finished. |
94 | |
161 | |
|
|
162 | All requests return objects of type L<IO::AIO::REQ> that allow further |
|
|
163 | manipulation of those requests while they are in-flight. |
|
|
164 | |
95 | 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 |
96 | 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 |
97 | request is being executed, the current working directory could have |
167 | request is being executed, the current working directory could have |
98 | changed. Alternatively, you can make sure that you never change the |
168 | changed. Alternatively, you can make sure that you never change the |
99 | current working directory. |
169 | current working directory. |
… | |
… | |
105 | 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) |
106 | use something else. |
176 | use something else. |
107 | |
177 | |
108 | =over 4 |
178 | =over 4 |
109 | |
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. |
|
|
207 | |
110 | =item aio_open $pathname, $flags, $mode, $callback |
208 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
111 | |
209 | |
112 | 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 |
113 | created filehandle for the file. |
211 | created filehandle for the file. |
114 | |
212 | |
115 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
213 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
… | |
… | |
132 | } else { |
230 | } else { |
133 | die "open failed: $!\n"; |
231 | die "open failed: $!\n"; |
134 | } |
232 | } |
135 | }; |
233 | }; |
136 | |
234 | |
137 | =item aio_close $fh, $callback |
235 | =item aio_close $fh, $callback->($status) |
138 | |
236 | |
139 | Asynchronously close a file and call the callback with the result |
237 | Asynchronously close a file and call the callback with the result |
140 | code. I<WARNING:> although accepted, you should not pass in a perl |
238 | code. I<WARNING:> although accepted, you should not pass in a perl |
141 | filehandle here, as perl will likely close the file descriptor another |
239 | filehandle here, as perl will likely close the file descriptor another |
142 | time when the filehandle is destroyed. Normally, you can safely call perls |
240 | time when the filehandle is destroyed. Normally, you can safely call perls |
143 | C<close> or just let filehandles go out of scope. |
241 | C<close> or just let filehandles go out of scope. |
144 | |
242 | |
145 | This is supposed to be a bug in the API, so that might change. It's |
243 | This is supposed to be a bug in the API, so that might change. It's |
146 | therefore best to avoid this function. |
244 | therefore best to avoid this function. |
147 | |
245 | |
148 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
246 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
149 | |
247 | |
150 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
248 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
151 | |
249 | |
152 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
250 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
153 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
251 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
154 | callback without the actual number of bytes read (or -1 on error, just |
252 | callback without the actual number of bytes read (or -1 on error, just |
155 | like the syscall). |
253 | like the syscall). |
… | |
… | |
164 | aio_read $fh, 7, 15, $buffer, 0, sub { |
262 | aio_read $fh, 7, 15, $buffer, 0, sub { |
165 | $_[0] > 0 or die "read error: $!"; |
263 | $_[0] > 0 or die "read error: $!"; |
166 | print "read $_[0] bytes: <$buffer>\n"; |
264 | print "read $_[0] bytes: <$buffer>\n"; |
167 | }; |
265 | }; |
168 | |
266 | |
|
|
267 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
268 | |
|
|
269 | Try to move the I<file> (directories not supported as either source or |
|
|
270 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
271 | the C<0> (error) or C<-1> ok. |
|
|
272 | |
|
|
273 | This is a composite request that tries to rename(2) the file first. If |
|
|
274 | rename files with C<EXDEV>, it creates the destination file with mode 0200 |
|
|
275 | and copies the contents of the source file into it using C<aio_sendfile>, |
|
|
276 | followed by restoring atime, mtime, access mode and uid/gid, in that |
|
|
277 | order, and unlinking the C<$srcpath>. |
|
|
278 | |
|
|
279 | If an error occurs, the partial destination file will be unlinked, if |
|
|
280 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
281 | errors are being ignored. |
|
|
282 | |
|
|
283 | =cut |
|
|
284 | |
|
|
285 | sub aio_move($$$) { |
|
|
286 | my ($src, $dst, $cb) = @_; |
|
|
287 | |
|
|
288 | my $grp = aio_group $cb; |
|
|
289 | |
|
|
290 | add $grp aio_rename $src, $dst, sub { |
|
|
291 | if ($_[0] && $! == EXDEV) { |
|
|
292 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
293 | if (my $src_fh = $_[0]) { |
|
|
294 | my @stat = stat $src_fh; |
|
|
295 | |
|
|
296 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
|
|
297 | if (my $dst_fh = $_[0]) { |
|
|
298 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
299 | close $src_fh; |
|
|
300 | |
|
|
301 | if ($_[0] == $stat[7]) { |
|
|
302 | utime $stat[8], $stat[9], $dst; |
|
|
303 | chmod $stat[2] & 07777, $dst_fh; |
|
|
304 | chown $stat[4], $stat[5], $dst_fh; |
|
|
305 | close $dst_fh; |
|
|
306 | |
|
|
307 | add $grp aio_unlink $src, sub { |
|
|
308 | $grp->result ($_[0]); |
|
|
309 | }; |
|
|
310 | } else { |
|
|
311 | my $errno = $!; |
|
|
312 | add $grp aio_unlink $dst, sub { |
|
|
313 | $! = $errno; |
|
|
314 | $grp->result (-1); |
|
|
315 | }; |
|
|
316 | } |
|
|
317 | }; |
|
|
318 | } else { |
|
|
319 | $grp->result (-1); |
|
|
320 | } |
|
|
321 | }, |
|
|
322 | |
|
|
323 | } else { |
|
|
324 | $grp->result (-1); |
|
|
325 | } |
|
|
326 | }; |
|
|
327 | } else { |
|
|
328 | $grp->result ($_[0]); |
|
|
329 | } |
|
|
330 | }; |
|
|
331 | |
|
|
332 | $grp |
|
|
333 | } |
|
|
334 | |
169 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback |
335 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
170 | |
336 | |
171 | 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 |
172 | reading at byte offset C<$in_offset>, and starts writing at the current |
338 | reading at byte offset C<$in_offset>, and starts writing at the current |
173 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
339 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
174 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
340 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
… | |
… | |
187 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
353 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
188 | provides the number of bytes written to C<$out_fh>. Only if the result |
354 | provides the number of bytes written to C<$out_fh>. Only if the result |
189 | value equals C<$length> one can assume that C<$length> bytes have been |
355 | value equals C<$length> one can assume that C<$length> bytes have been |
190 | read. |
356 | read. |
191 | |
357 | |
192 | =item aio_readahead $fh,$offset,$length, $callback |
358 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
193 | |
359 | |
194 | C<aio_readahead> populates the page cache with data from a file so that |
360 | C<aio_readahead> populates the page cache with data from a file so that |
195 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
361 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
196 | argument specifies the starting point from which data is to be read and |
362 | argument specifies the starting point from which data is to be read and |
197 | C<$length> specifies the number of bytes to be read. I/O is performed in |
363 | C<$length> specifies the number of bytes to be read. I/O is performed in |
… | |
… | |
201 | file. The current file offset of the file is left unchanged. |
367 | file. The current file offset of the file is left unchanged. |
202 | |
368 | |
203 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
369 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
204 | emulated by simply reading the data, which would have a similar effect. |
370 | emulated by simply reading the data, which would have a similar effect. |
205 | |
371 | |
206 | =item aio_stat $fh_or_path, $callback |
372 | =item aio_stat $fh_or_path, $callback->($status) |
207 | |
373 | |
208 | =item aio_lstat $fh, $callback |
374 | =item aio_lstat $fh, $callback->($status) |
209 | |
375 | |
210 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
376 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
211 | be called after the stat and the results will be available using C<stat _> |
377 | be called after the stat and the results will be available using C<stat _> |
212 | or C<-s _> etc... |
378 | or C<-s _> etc... |
213 | |
379 | |
… | |
… | |
223 | aio_stat "/etc/passwd", sub { |
389 | aio_stat "/etc/passwd", sub { |
224 | $_[0] and die "stat failed: $!"; |
390 | $_[0] and die "stat failed: $!"; |
225 | print "size is ", -s _, "\n"; |
391 | print "size is ", -s _, "\n"; |
226 | }; |
392 | }; |
227 | |
393 | |
228 | =item aio_unlink $pathname, $callback |
394 | =item aio_unlink $pathname, $callback->($status) |
229 | |
395 | |
230 | Asynchronously unlink (delete) a file and call the callback with the |
396 | Asynchronously unlink (delete) a file and call the callback with the |
231 | result code. |
397 | result code. |
232 | |
398 | |
|
|
399 | =item aio_link $srcpath, $dstpath, $callback->($status) |
|
|
400 | |
|
|
401 | Asynchronously create a new link to the existing object at C<$srcpath> at |
|
|
402 | the path C<$dstpath> and call the callback with the result code. |
|
|
403 | |
|
|
404 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
405 | |
|
|
406 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
|
|
407 | the path C<$dstpath> and call the callback with the result code. |
|
|
408 | |
|
|
409 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
410 | |
|
|
411 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
|
|
412 | rename(2) and call the callback with the result code. |
|
|
413 | |
233 | =item aio_rmdir $pathname, $callback |
414 | =item aio_rmdir $pathname, $callback->($status) |
234 | |
415 | |
235 | Asynchronously rmdir (delete) a directory and call the callback with the |
416 | Asynchronously rmdir (delete) a directory and call the callback with the |
236 | result code. |
417 | result code. |
237 | |
418 | |
238 | =item aio_readdir $pathname $callback |
419 | =item aio_readdir $pathname, $callback->($entries) |
239 | |
420 | |
240 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
421 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
241 | directory (i.e. opendir + readdir + closedir). The entries will not be |
422 | directory (i.e. opendir + readdir + closedir). The entries will not be |
242 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
423 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
243 | |
424 | |
244 | The callback a single argument which is either C<undef> or an array-ref |
425 | The callback a single argument which is either C<undef> or an array-ref |
245 | with the filenames. |
426 | with the filenames. |
246 | |
427 | |
|
|
428 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
|
|
429 | |
|
|
430 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
|
|
431 | efficiently separate the entries of directory C<$path> into two sets of |
|
|
432 | names, directories you can recurse into (directories), and ones you cannot |
|
|
433 | recurse into (everything else, including symlinks to directories). |
|
|
434 | |
|
|
435 | C<aio_scandir> is a composite request that creates of many sub requests_ |
|
|
436 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
|
|
437 | this function generates. If it is C<< <= 0 >>, then a suitable default |
|
|
438 | will be chosen (currently 6). |
|
|
439 | |
|
|
440 | On error, the callback is called without arguments, otherwise it receives |
|
|
441 | two array-refs with path-relative entry names. |
|
|
442 | |
|
|
443 | Example: |
|
|
444 | |
|
|
445 | aio_scandir $dir, 0, sub { |
|
|
446 | my ($dirs, $nondirs) = @_; |
|
|
447 | print "real directories: @$dirs\n"; |
|
|
448 | print "everything else: @$nondirs\n"; |
|
|
449 | }; |
|
|
450 | |
|
|
451 | Implementation notes. |
|
|
452 | |
|
|
453 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
|
|
454 | |
|
|
455 | After reading the directory, the modification time, size etc. of the |
|
|
456 | directory before and after the readdir is checked, and if they match (and |
|
|
457 | isn't the current time), the link count will be used to decide how many |
|
|
458 | entries are directories (if >= 2). Otherwise, no knowledge of the number |
|
|
459 | of subdirectories will be assumed. |
|
|
460 | |
|
|
461 | Then entries will be sorted into likely directories (everything without |
|
|
462 | a non-initial dot currently) and likely non-directories (everything |
|
|
463 | else). Then every entry plus an appended C</.> will be C<stat>'ed, |
|
|
464 | likely directories first. If that succeeds, it assumes that the entry |
|
|
465 | is a directory or a symlink to directory (which will be checked |
|
|
466 | seperately). This is often faster than stat'ing the entry itself because |
|
|
467 | filesystems might detect the type of the entry without reading the inode |
|
|
468 | data (e.g. ext2fs filetype feature). |
|
|
469 | |
|
|
470 | If the known number of directories (link count - 2) has been reached, the |
|
|
471 | rest of the entries is assumed to be non-directories. |
|
|
472 | |
|
|
473 | This only works with certainty on POSIX (= UNIX) filesystems, which |
|
|
474 | fortunately are the vast majority of filesystems around. |
|
|
475 | |
|
|
476 | It will also likely work on non-POSIX filesystems with reduced efficiency |
|
|
477 | as those tend to return 0 or 1 as link counts, which disables the |
|
|
478 | directory counting heuristic. |
|
|
479 | |
|
|
480 | =cut |
|
|
481 | |
|
|
482 | sub aio_scandir($$$) { |
|
|
483 | my ($path, $maxreq, $cb) = @_; |
|
|
484 | |
|
|
485 | my $grp = aio_group $cb; |
|
|
486 | |
|
|
487 | $maxreq = 6 if $maxreq <= 0; |
|
|
488 | |
|
|
489 | # stat once |
|
|
490 | add $grp aio_stat $path, sub { |
|
|
491 | return $grp->result () if $_[0]; |
|
|
492 | my $now = time; |
|
|
493 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
494 | |
|
|
495 | # read the directory entries |
|
|
496 | add $grp aio_readdir $path, sub { |
|
|
497 | my $entries = shift |
|
|
498 | or return $grp->result (); |
|
|
499 | |
|
|
500 | # stat the dir another time |
|
|
501 | add $grp aio_stat $path, sub { |
|
|
502 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
|
|
503 | |
|
|
504 | my $ndirs; |
|
|
505 | |
|
|
506 | # take the slow route if anything looks fishy |
|
|
507 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
|
|
508 | $ndirs = -1; |
|
|
509 | } else { |
|
|
510 | # if nlink == 2, we are finished |
|
|
511 | # on non-posix-fs's, we rely on nlink < 2 |
|
|
512 | $ndirs = (stat _)[3] - 2 |
|
|
513 | or return $grp->result ([], $entries); |
|
|
514 | } |
|
|
515 | |
|
|
516 | # sort into likely dirs and likely nondirs |
|
|
517 | # dirs == files without ".", short entries first |
|
|
518 | $entries = [map $_->[0], |
|
|
519 | sort { $b->[1] cmp $a->[1] } |
|
|
520 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
|
|
521 | @$entries]; |
|
|
522 | |
|
|
523 | my (@dirs, @nondirs); |
|
|
524 | |
|
|
525 | my $statgrp = add $grp aio_group sub { |
|
|
526 | $grp->result (\@dirs, \@nondirs); |
|
|
527 | }; |
|
|
528 | |
|
|
529 | limit $statgrp $maxreq; |
|
|
530 | feed $statgrp sub { |
|
|
531 | return unless @$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 | } |
|
|
550 | } |
|
|
551 | } |
|
|
552 | }; |
|
|
553 | }; |
|
|
554 | }; |
|
|
555 | }; |
|
|
556 | }; |
|
|
557 | |
|
|
558 | $grp |
|
|
559 | } |
|
|
560 | |
247 | =item aio_fsync $fh, $callback |
561 | =item aio_fsync $fh, $callback->($status) |
248 | |
562 | |
249 | Asynchronously call fsync on the given filehandle and call the callback |
563 | Asynchronously call fsync on the given filehandle and call the callback |
250 | with the fsync result code. |
564 | with the fsync result code. |
251 | |
565 | |
252 | =item aio_fdatasync $fh, $callback |
566 | =item aio_fdatasync $fh, $callback->($status) |
253 | |
567 | |
254 | Asynchronously call fdatasync on the given filehandle and call the |
568 | Asynchronously call fdatasync on the given filehandle and call the |
255 | callback with the fdatasync result code. |
569 | callback with the fdatasync result code. |
256 | |
570 | |
257 | 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 |
258 | detected, it will be emulated by calling C<fsync> instead. |
572 | detected, it will be emulated by calling C<fsync> instead. |
|
|
573 | |
|
|
574 | =item aio_group $callback->(...) |
|
|
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 | |
|
|
608 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
|
|
609 | |
|
|
610 | Mainly used for debugging and benchmarking, this aio request puts one of |
|
|
611 | the request workers to sleep for the given time. |
|
|
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 | |
|
|
618 | =back |
|
|
619 | |
|
|
620 | =head2 IO::AIO::REQ CLASS |
|
|
621 | |
|
|
622 | All non-aggregate C<aio_*> functions return an object of this class when |
|
|
623 | called in non-void context. |
|
|
624 | |
|
|
625 | =over 4 |
|
|
626 | |
|
|
627 | =item cancel $req |
|
|
628 | |
|
|
629 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
630 | when entering the B<execute> state and skipping calling the callback when |
|
|
631 | entering the the B<result> state, but will leave the request otherwise |
|
|
632 | untouched. That means that requests that currently execute will not be |
|
|
633 | stopped and resources held by the request will not be freed prematurely. |
|
|
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 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
688 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
689 | this kind of concurrency-limiting. |
|
|
690 | |
|
|
691 | =back |
|
|
692 | |
|
|
693 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
694 | will finish very quickly. If they contain only requests that are in the |
|
|
695 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
696 | exist. |
|
|
697 | |
|
|
698 | That means after creating a group you have some time to add requests. And |
|
|
699 | in the callbacks of those requests, you can add further requests to the |
|
|
700 | group. And only when all those requests have finished will the the group |
|
|
701 | itself finish. |
|
|
702 | |
|
|
703 | =over 4 |
|
|
704 | |
|
|
705 | =item add $grp ... |
|
|
706 | |
|
|
707 | =item $grp->add (...) |
|
|
708 | |
|
|
709 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
|
|
710 | be added, including other groups, as long as you do not create circular |
|
|
711 | dependencies. |
|
|
712 | |
|
|
713 | Returns all its arguments. |
|
|
714 | |
|
|
715 | =item $grp->cancel_subs |
|
|
716 | |
|
|
717 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
718 | itself. Useful when you queued a lot of events but got a result early. |
|
|
719 | |
|
|
720 | =item $grp->result (...) |
|
|
721 | |
|
|
722 | Set the result value(s) that will be passed to the group callback when all |
|
|
723 | subrequests have finished. By default, no argument will be passed. |
|
|
724 | |
|
|
725 | =item feed $grp $callback->($grp) |
|
|
726 | |
|
|
727 | Sets a feeder/generator on this group: every group can have an attached |
|
|
728 | generator that generates requests if idle. The idea behind this is that, |
|
|
729 | although you could just queue as many requests as you want in a group, |
|
|
730 | this might starve other requests for a potentially long time. For |
|
|
731 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
|
|
732 | requests, delaying any later requests for a long time. |
|
|
733 | |
|
|
734 | To avoid this, and allow incremental generation of requests, you can |
|
|
735 | instead a group and set a feeder on it that generates those requests. The |
|
|
736 | feed callback will be called whenever there are few enough (see C<limit>, |
|
|
737 | below) requests active in the group itself and is expected to queue more |
|
|
738 | requests. |
|
|
739 | |
|
|
740 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
|
|
741 | not impose any limits). |
|
|
742 | |
|
|
743 | If the feed does not queue more requests when called, it will be |
|
|
744 | automatically removed from the group. |
|
|
745 | |
|
|
746 | If the feed limit is C<0>, it will be set to C<2> automatically. |
|
|
747 | |
|
|
748 | Example: |
|
|
749 | |
|
|
750 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
751 | |
|
|
752 | my $grp = aio_group sub { print "finished\n" }; |
|
|
753 | limit $grp 4; |
|
|
754 | feed $grp sub { |
|
|
755 | my $file = pop @files |
|
|
756 | or return; |
|
|
757 | |
|
|
758 | add $grp aio_stat $file, sub { ... }; |
|
|
759 | }; |
|
|
760 | |
|
|
761 | =item limit $grp $num |
|
|
762 | |
|
|
763 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
764 | the group contains less than this many requests. |
|
|
765 | |
|
|
766 | Setting the limit to C<0> will pause the feeding process. |
259 | |
767 | |
260 | =back |
768 | =back |
261 | |
769 | |
262 | =head2 SUPPORT FUNCTIONS |
770 | =head2 SUPPORT FUNCTIONS |
263 | |
771 | |
… | |
… | |
321 | IO::AIO::poll_wait, IO::AIO::poll_cb |
829 | IO::AIO::poll_wait, IO::AIO::poll_cb |
322 | if IO::AIO::nreqs; |
830 | if IO::AIO::nreqs; |
323 | |
831 | |
324 | =item IO::AIO::min_parallel $nthreads |
832 | =item IO::AIO::min_parallel $nthreads |
325 | |
833 | |
326 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
834 | Set the minimum number of AIO threads to C<$nthreads>. The current |
327 | is C<4>, which means four asynchronous operations can be done at one time |
835 | default is C<8>, which means eight asynchronous operations can execute |
328 | (the number of outstanding operations, however, is unlimited). |
836 | concurrently at any one time (the number of outstanding requests, |
|
|
837 | however, is unlimited). |
329 | |
838 | |
330 | IO::AIO starts threads only on demand, when an AIO request is queued and |
839 | IO::AIO starts threads only on demand, when an AIO request is queued and |
331 | no free thread exists. |
840 | no free thread exists. |
332 | |
841 | |
333 | It is recommended to keep the number of threads low, as some Linux |
842 | It is recommended to keep the number of threads relatively low, as some |
334 | kernel versions will scale negatively with the number of threads (higher |
843 | Linux kernel versions will scale negatively with the number of threads |
335 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
844 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
336 | threads should be fine. |
845 | versions, 4-32 threads should be fine. |
337 | |
846 | |
338 | Under most circumstances you don't need to call this function, as the |
847 | Under most circumstances you don't need to call this function, as the |
339 | module selects a default that is suitable for low to moderate load. |
848 | module selects a default that is suitable for low to moderate load. |
340 | |
849 | |
341 | =item IO::AIO::max_parallel $nthreads |
850 | =item IO::AIO::max_parallel $nthreads |
… | |
… | |
352 | |
861 | |
353 | Under normal circumstances you don't need to call this function. |
862 | Under normal circumstances you don't need to call this function. |
354 | |
863 | |
355 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
864 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
356 | |
865 | |
|
|
866 | [DEPRECATED] |
|
|
867 | |
357 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
868 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
358 | try to queue up more than this number of requests, the caller will block until |
869 | try to queue up more than this number of requests, the caller will block until |
359 | some requests have been handled. |
870 | some requests have been handled. |
360 | |
871 | |
361 | The default is very large, so normally there is no practical limit. If you |
872 | The default is very large, so normally there is no practical limit. If you |
362 | queue up many requests in a loop it often improves speed if you set |
873 | queue up many requests in a loop it often improves speed if you set |
363 | this to a relatively low number, such as C<100>. |
874 | this to a relatively low number, such as C<100>. |
|
|
875 | |
|
|
876 | This function does not work well together with C<aio_group>'s, and their |
|
|
877 | feeder interface is better suited to limiting concurrency, so do not use |
|
|
878 | this function. |
364 | |
879 | |
365 | Under normal circumstances you don't need to call this function. |
880 | Under normal circumstances you don't need to call this function. |
366 | |
881 | |
367 | =back |
882 | =back |
368 | |
883 | |
… | |
… | |
382 | or return undef; |
897 | or return undef; |
383 | |
898 | |
384 | *$sym |
899 | *$sym |
385 | } |
900 | } |
386 | |
901 | |
387 | min_parallel 4; |
902 | min_parallel 8; |
388 | |
903 | |
389 | END { |
904 | END { |
390 | max_parallel 0; |
905 | max_parallel 0; |
391 | } |
906 | } |
392 | |
907 | |
393 | 1; |
908 | 1; |
394 | |
909 | |
395 | =head2 FORK BEHAVIOUR |
910 | =head2 FORK BEHAVIOUR |
396 | |
911 | |
|
|
912 | This module should do "the right thing" when the process using it forks: |
|
|
913 | |
397 | Before the fork, IO::AIO enters a quiescent state where no requests |
914 | Before the fork, IO::AIO enters a quiescent state where no requests |
398 | can be added in other threads and no results will be processed. After |
915 | can be added in other threads and no results will be processed. After |
399 | the fork the parent simply leaves the quiescent state and continues |
916 | the fork the parent simply leaves the quiescent state and continues |
400 | request/result processing, while the child clears the request/result |
917 | request/result processing, while the child frees the request/result queue |
401 | queue (so the requests started before the fork will only be handled in |
918 | (so that the requests started before the fork will only be handled in the |
402 | the parent). Threats will be started on demand until the limit ste in the |
919 | parent). Threads will be started on demand until the limit set in the |
403 | parent process has been reached again. |
920 | parent process has been reached again. |
404 | |
921 | |
|
|
922 | In short: the parent will, after a short pause, continue as if fork had |
|
|
923 | not been called, while the child will act as if IO::AIO has not been used |
|
|
924 | yet. |
|
|
925 | |
|
|
926 | =head2 MEMORY USAGE |
|
|
927 | |
|
|
928 | Per-request usage: |
|
|
929 | |
|
|
930 | Each aio request uses - depending on your architecture - around 100-200 |
|
|
931 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
|
|
932 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
|
|
933 | scalars and other data passed into aio requests will also be locked and |
|
|
934 | will consume memory till the request has entered the done state. |
|
|
935 | |
|
|
936 | This is now awfully much, so queuing lots of requests is not usually a |
|
|
937 | problem. |
|
|
938 | |
|
|
939 | Per-thread usage: |
|
|
940 | |
|
|
941 | In the execution phase, some aio requests require more memory for |
|
|
942 | temporary buffers, and each thread requires a stack and other data |
|
|
943 | structures (usually around 16k-128k, depending on the OS). |
|
|
944 | |
|
|
945 | =head1 KNOWN BUGS |
|
|
946 | |
|
|
947 | Known bugs will be fixed in the next release. |
|
|
948 | |
405 | =head1 SEE ALSO |
949 | =head1 SEE ALSO |
406 | |
950 | |
407 | L<Coro>, L<Linux::AIO>. |
951 | L<Coro::AIO>. |
408 | |
952 | |
409 | =head1 AUTHOR |
953 | =head1 AUTHOR |
410 | |
954 | |
411 | Marc Lehmann <schmorp@schmorp.de> |
955 | Marc Lehmann <schmorp@schmorp.de> |
412 | http://home.schmorp.de/ |
956 | http://home.schmorp.de/ |