… | |
… | |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use IO::AIO; |
7 | use IO::AIO; |
8 | |
8 | |
|
|
9 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
|
|
10 | my ($fh) = @_; |
|
|
11 | ... |
|
|
12 | }; |
|
|
13 | |
|
|
14 | aio_unlink "/tmp/file", sub { }; |
|
|
15 | |
|
|
16 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
|
|
17 | $_[0] > 0 or die "read error: $!"; |
|
|
18 | }; |
|
|
19 | |
|
|
20 | # Event |
|
|
21 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
22 | poll => 'r', |
|
|
23 | cb => \&IO::AIO::poll_cb); |
|
|
24 | |
|
|
25 | # Glib/Gtk2 |
|
|
26 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
27 | \&IO::AIO::poll_cb; |
|
|
28 | |
|
|
29 | # Tk |
|
|
30 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
31 | readable => \&IO::AIO::poll_cb); |
|
|
32 | |
9 | =head1 DESCRIPTION |
33 | =head1 DESCRIPTION |
10 | |
34 | |
11 | This module implements asynchronous I/O using whatever means your |
35 | This module implements asynchronous I/O using whatever means your |
12 | operating system supports. Currently, it falls back to Linux::AIO if that |
36 | operating system supports. |
13 | module is available, or uses pthreads to emulato aio functionality. |
|
|
14 | |
37 | |
15 | Currently, in this module a number of threads are started that execute |
38 | Currently, a number of threads are started that execute your read/writes |
16 | your read/writes and signal their completion. You don't need thread |
39 | and signal their completion. You don't need thread support in your libc or |
17 | support in your libc or perl, and the threads created by this module will |
40 | perl, and the threads created by this module will not be visible to the |
18 | not be visible to the pthreads library. |
41 | pthreads library. In the future, this module might make use of the native |
|
|
42 | aio functions available on many operating systems. However, they are often |
|
|
43 | not well-supported (Linux doesn't allow them on normal files currently, |
|
|
44 | for example), and they would only support aio_read and aio_write, so the |
|
|
45 | remaining functionality would have to be implemented using threads anyway. |
19 | |
46 | |
20 | Although the module will work with in the presence of other threads, it is |
47 | Although the module will work with in the presence of other threads, it is |
21 | not reentrant, so use appropriate locking yourself. |
48 | currently not reentrant, so use appropriate locking yourself. |
22 | |
49 | |
23 | =head2 API NOTES |
50 | =cut |
|
|
51 | |
|
|
52 | package IO::AIO; |
|
|
53 | |
|
|
54 | use base 'Exporter'; |
|
|
55 | |
|
|
56 | use Fcntl (); |
|
|
57 | |
|
|
58 | BEGIN { |
|
|
59 | $VERSION = 0.3; |
|
|
60 | |
|
|
61 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
|
|
62 | aio_fsync aio_fdatasync aio_readahead); |
|
|
63 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
|
|
64 | |
|
|
65 | require XSLoader; |
|
|
66 | XSLoader::load IO::AIO, $VERSION; |
|
|
67 | } |
|
|
68 | |
|
|
69 | =head1 FUNCTIONS |
|
|
70 | |
|
|
71 | =head2 AIO FUNCTIONS |
24 | |
72 | |
25 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
73 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
26 | with the same name (sans C<aio_>). The arguments are similar or identical, |
74 | with the same name (sans C<aio_>). The arguments are similar or identical, |
27 | and they all accept an additional C<$callback> argument which must be |
75 | and they all accept an additional C<$callback> argument which must be |
28 | a code reference. This code reference will get called with the syscall |
76 | a code reference. This code reference will get called with the syscall |
… | |
… | |
37 | directory could have changed. Alternatively, you can make sure that you |
85 | directory could have changed. Alternatively, you can make sure that you |
38 | never change the current working directory. |
86 | never change the current working directory. |
39 | |
87 | |
40 | =over 4 |
88 | =over 4 |
41 | |
89 | |
42 | =cut |
|
|
43 | |
|
|
44 | package IO::AIO; |
|
|
45 | |
|
|
46 | use base 'Exporter'; |
|
|
47 | |
|
|
48 | BEGIN { |
|
|
49 | $VERSION = 0.1; |
|
|
50 | |
|
|
51 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
|
|
52 | aio_fsync aio_fdatasync aio_readahead); |
|
|
53 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs); |
|
|
54 | |
|
|
55 | require XSLoader; |
|
|
56 | XSLoader::load IO::AIO, $VERSION; |
|
|
57 | } |
|
|
58 | |
|
|
59 | =item IO::AIO::min_parallel $nthreads |
|
|
60 | |
|
|
61 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
|
|
62 | C<1>, which means a single asynchronous operation can be done at one time |
|
|
63 | (the number of outstanding operations, however, is unlimited). |
|
|
64 | |
|
|
65 | It is recommended to keep the number of threads low, as some linux |
|
|
66 | kernel versions will scale negatively with the number of threads (higher |
|
|
67 | parallelity => MUCH higher latency). |
|
|
68 | |
|
|
69 | Under normal circumstances you don't need to call this function, as this |
|
|
70 | module automatically starts a single async thread. |
|
|
71 | |
|
|
72 | =item IO::AIO::max_parallel $nthreads |
|
|
73 | |
|
|
74 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
|
|
75 | the specified number of threads are currently running, kill them. This |
|
|
76 | function blocks until the limit is reached. |
|
|
77 | |
|
|
78 | This module automatically runs C<max_parallel 0> at program end, to ensure |
|
|
79 | that all threads are killed and that there are no outstanding requests. |
|
|
80 | |
|
|
81 | Under normal circumstances you don't need to call this function. |
|
|
82 | |
|
|
83 | =item $fileno = IO::AIO::poll_fileno |
|
|
84 | |
|
|
85 | Return the I<request result pipe filehandle>. This filehandle must be |
|
|
86 | polled for reading by some mechanism outside this module (e.g. Event |
|
|
87 | or select, see below). If the pipe becomes readable you have to call |
|
|
88 | C<poll_cb> to check the results. |
|
|
89 | |
|
|
90 | See C<poll_cb> for an example. |
|
|
91 | |
|
|
92 | =item IO::AIO::poll_cb |
|
|
93 | |
|
|
94 | Process all outstanding events on the result pipe. You have to call this |
|
|
95 | regularly. Returns the number of events processed. Returns immediately |
|
|
96 | when no events are outstanding. |
|
|
97 | |
|
|
98 | You can use Event to multiplex, e.g.: |
|
|
99 | |
|
|
100 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
101 | poll => 'r', async => 1, |
|
|
102 | cb => \&IO::AIO::poll_cb); |
|
|
103 | |
|
|
104 | =item IO::AIO::poll_wait |
|
|
105 | |
|
|
106 | Wait till the result filehandle becomes ready for reading (simply does a |
|
|
107 | select on the filehandle. This is useful if you want to synchronously wait |
|
|
108 | for some requests to finish). |
|
|
109 | |
|
|
110 | See C<nreqs> for an example. |
|
|
111 | |
|
|
112 | =item IO::AIO::nreqs |
|
|
113 | |
|
|
114 | Returns the number of requests currently outstanding. |
|
|
115 | |
|
|
116 | Example: wait till there are no outstanding requests anymore: |
|
|
117 | |
|
|
118 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
119 | while IO::AIO::nreqs; |
|
|
120 | |
|
|
121 | =item aio_open $pathname, $flags, $mode, $callback |
90 | =item aio_open $pathname, $flags, $mode, $callback |
122 | |
91 | |
123 | Asynchronously open or create a file and call the callback with the |
92 | Asynchronously open or create a file and call the callback with a newly |
124 | filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this |
93 | created filehandle for the file. |
125 | might change in the future). |
|
|
126 | |
94 | |
127 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
95 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
128 | for an explanation. |
96 | for an explanation. |
129 | |
97 | |
130 | The C<$mode> argument is a bitmask. See the C<Fcntl> module for a |
98 | The C<$mode> argument is a bitmask. See the C<Fcntl> module for a |
131 | list. They are the same as used in C<sysopen>. |
99 | list. They are the same as used in C<sysopen>. |
132 | |
100 | |
133 | Example: |
101 | Example: |
134 | |
102 | |
135 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
103 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
136 | if ($_[0] >= 0) { |
104 | if ($_[0]) { |
137 | open my $fh, "<&$_[0]"; # create a copy for perl |
|
|
138 | aio_close $_[0], sub { }; # close the aio handle |
|
|
139 | print "open successful, fh is $fh\n"; |
105 | print "open successful, fh is $_[0]\n"; |
140 | ... |
106 | ... |
141 | } else { |
107 | } else { |
142 | die "open failed: $!\n"; |
108 | die "open failed: $!\n"; |
143 | } |
109 | } |
144 | }; |
110 | }; |
145 | |
111 | |
146 | =item aio_close $fh, $callback |
112 | =item aio_close $fh, $callback |
147 | |
113 | |
148 | Asynchronously close a file and call the callback with the result code. |
114 | Asynchronously close a file and call the callback with the result |
|
|
115 | code. I<WARNING:> although accepted, you should not pass in a perl |
|
|
116 | filehandle here, as perl will likely close the file descriptor itself when |
|
|
117 | the filehandle is destroyed. Normally, you can safely call perls C<close> |
|
|
118 | or just let filehandles go out of scope. |
149 | |
119 | |
150 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
120 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
151 | |
121 | |
152 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
122 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
153 | |
123 | |
… | |
… | |
158 | |
128 | |
159 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at |
129 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at |
160 | offset C<0> within the scalar: |
130 | offset C<0> within the scalar: |
161 | |
131 | |
162 | aio_read $fh, 7, 15, $buffer, 0, sub { |
132 | aio_read $fh, 7, 15, $buffer, 0, sub { |
163 | $_[0] >= 0 or die "read error: $!"; |
133 | $_[0] > 0 or die "read error: $!"; |
164 | print "read <$buffer>\n"; |
134 | print "read $_[0] bytes: <$buffer>\n"; |
165 | }; |
135 | }; |
166 | |
136 | |
167 | =item aio_readahead $fh,$offset,$length, $callback |
137 | =item aio_readahead $fh,$offset,$length, $callback |
168 | |
138 | |
169 | Asynchronously reads the specified byte range into the page cache, using |
139 | Asynchronously reads the specified byte range into the page cache, using |
… | |
… | |
214 | =item aio_fdatasync $fh, $callback |
184 | =item aio_fdatasync $fh, $callback |
215 | |
185 | |
216 | Asynchronously call fdatasync on the given filehandle and call the |
186 | Asynchronously call fdatasync on the given filehandle and call the |
217 | callback with the fdatasync result code. |
187 | callback with the fdatasync result code. |
218 | |
188 | |
|
|
189 | =back |
|
|
190 | |
|
|
191 | =head2 SUPPORT FUNCTIONS |
|
|
192 | |
|
|
193 | =over 4 |
|
|
194 | |
|
|
195 | =item $fileno = IO::AIO::poll_fileno |
|
|
196 | |
|
|
197 | Return the I<request result pipe filehandle>. This filehandle must be |
|
|
198 | polled for reading by some mechanism outside this module (e.g. Event |
|
|
199 | or select, see below). If the pipe becomes readable you have to call |
|
|
200 | C<poll_cb> to check the results. |
|
|
201 | |
|
|
202 | See C<poll_cb> for an example. |
|
|
203 | |
|
|
204 | =item IO::AIO::poll_cb |
|
|
205 | |
|
|
206 | Process all outstanding events on the result pipe. You have to call this |
|
|
207 | regularly. Returns the number of events processed. Returns immediately |
|
|
208 | when no events are outstanding. |
|
|
209 | |
|
|
210 | You can use Event to multiplex, e.g.: |
|
|
211 | |
|
|
212 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
213 | poll => 'r', async => 1, |
|
|
214 | cb => \&IO::AIO::poll_cb); |
|
|
215 | |
|
|
216 | =item IO::AIO::poll_wait |
|
|
217 | |
|
|
218 | Wait till the result filehandle becomes ready for reading (simply does a |
|
|
219 | select on the filehandle. This is useful if you want to synchronously wait |
|
|
220 | for some requests to finish). |
|
|
221 | |
|
|
222 | See C<nreqs> for an example. |
|
|
223 | |
|
|
224 | =item IO::AIO::nreqs |
|
|
225 | |
|
|
226 | Returns the number of requests currently outstanding. |
|
|
227 | |
|
|
228 | Example: wait till there are no outstanding requests anymore: |
|
|
229 | |
|
|
230 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
231 | while IO::AIO::nreqs; |
|
|
232 | |
|
|
233 | =item IO::AIO::min_parallel $nthreads |
|
|
234 | |
|
|
235 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
|
|
236 | C<1>, which means a single asynchronous operation can be done at one time |
|
|
237 | (the number of outstanding operations, however, is unlimited). |
|
|
238 | |
|
|
239 | It is recommended to keep the number of threads low, as some Linux |
|
|
240 | kernel versions will scale negatively with the number of threads (higher |
|
|
241 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
|
|
242 | threads should be fine. |
|
|
243 | |
|
|
244 | Under normal circumstances you don't need to call this function, as this |
|
|
245 | module automatically starts some threads (the exact number might change, |
|
|
246 | and is currently 4). |
|
|
247 | |
|
|
248 | =item IO::AIO::max_parallel $nthreads |
|
|
249 | |
|
|
250 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
|
|
251 | the specified number of threads are currently running, kill them. This |
|
|
252 | function blocks until the limit is reached. |
|
|
253 | |
|
|
254 | This module automatically runs C<max_parallel 0> at program end, to ensure |
|
|
255 | that all threads are killed and that there are no outstanding requests. |
|
|
256 | |
|
|
257 | Under normal circumstances you don't need to call this function. |
|
|
258 | |
|
|
259 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
|
|
260 | |
|
|
261 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
|
|
262 | try to queue up more than this number of requests, the caller will block until |
|
|
263 | some requests have been handled. |
|
|
264 | |
|
|
265 | The default is very large, so normally there is no practical limit. If you |
|
|
266 | queue up many requests in a loop it it often improves speed if you set |
|
|
267 | this to a relatively low number, such as C<100>. |
|
|
268 | |
|
|
269 | Under normal circumstances you don't need to call this function. |
|
|
270 | |
|
|
271 | =back |
|
|
272 | |
219 | =cut |
273 | =cut |
|
|
274 | |
|
|
275 | # support function to convert a fd into a perl filehandle |
|
|
276 | sub _fd2fh { |
|
|
277 | return undef if $_[0] < 0; |
|
|
278 | |
|
|
279 | # try to be perl5.6-compatible |
|
|
280 | local *AIO_FH; |
|
|
281 | open AIO_FH, "+<&=$_[0]" |
|
|
282 | or return undef; |
|
|
283 | |
|
|
284 | *AIO_FH |
|
|
285 | } |
220 | |
286 | |
221 | min_parallel 4; |
287 | min_parallel 4; |
222 | |
288 | |
223 | END { |
289 | END { |
224 | max_parallel 0; |
290 | max_parallel 0; |
225 | } |
291 | } |
226 | |
292 | |
227 | 1; |
293 | 1; |
228 | |
294 | |
229 | =back |
|
|
230 | |
|
|
231 | =head1 BUGS |
|
|
232 | |
|
|
233 | - aio_open gives a fd, but all other functions expect a perl filehandle. |
|
|
234 | |
|
|
235 | =head1 SEE ALSO |
295 | =head1 SEE ALSO |
236 | |
296 | |
237 | L<Coro>, L<Linux::AIO>. |
297 | L<Coro>, L<Linux::AIO>. |
238 | |
298 | |
239 | =head1 AUTHOR |
299 | =head1 AUTHOR |