… | |
… | |
12 | }; |
12 | }; |
13 | |
13 | |
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 | |
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 | \&IO::AIO::poll_cb; |
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 | |
|
|
47 | # Danga::Socket integration |
|
|
48 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
49 | \&IO::AIO::poll_cb); |
|
|
50 | |
33 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
34 | |
52 | |
35 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
36 | operating system supports. |
54 | operating system supports. |
37 | |
55 | |
38 | 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 |
39 | 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 |
40 | 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 |
41 | 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 |
42 | aio functions available on many operating systems. However, they are often |
60 | functions available on many operating systems. However, they are often |
43 | 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 |
44 | 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 |
45 | 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. |
46 | |
65 | |
47 | 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-) |
48 | currently not reentrant, so use appropriate locking yourself. |
67 | threads, it is currently not reentrant in any way, so use appropriate |
|
|
68 | locking yourself, always call C<poll_cb> from within the same thread, or |
|
|
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). |
49 | |
120 | |
50 | =cut |
121 | =cut |
51 | |
122 | |
52 | package IO::AIO; |
123 | package IO::AIO; |
53 | |
124 | |
|
|
125 | no warnings; |
|
|
126 | use strict 'vars'; |
|
|
127 | |
54 | use base 'Exporter'; |
128 | use base 'Exporter'; |
55 | |
129 | |
56 | use Fcntl (); |
|
|
57 | |
|
|
58 | BEGIN { |
130 | BEGIN { |
59 | $VERSION = 0.2; |
131 | our $VERSION = '2.0'; |
60 | |
132 | |
61 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
133 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
62 | aio_fsync aio_fdatasync aio_readahead); |
134 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
63 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
135 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
|
|
136 | aio_copy aio_group aio_nop aio_mknod); |
|
|
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 nready npending); |
|
|
140 | |
|
|
141 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
64 | |
142 | |
65 | require XSLoader; |
143 | require XSLoader; |
66 | XSLoader::load IO::AIO, $VERSION; |
144 | XSLoader::load ("IO::AIO", $VERSION); |
67 | } |
145 | } |
68 | |
146 | |
69 | =head1 FUNCTIONS |
147 | =head1 FUNCTIONS |
70 | |
148 | |
71 | =head2 AIO FUNCTIONS |
149 | =head2 AIO FUNCTIONS |
72 | |
150 | |
73 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
151 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
74 | with the same name (sans C<aio_>). The arguments are similar or identical, |
152 | with the same name (sans C<aio_>). The arguments are similar or identical, |
75 | and they all accept an additional C<$callback> argument which must be |
153 | and they all accept an additional (and optional) C<$callback> argument |
76 | a code reference. This code reference will get called with the syscall |
154 | which must be a code reference. This code reference will get called with |
77 | return code (e.g. most syscalls return C<-1> on error, unlike perl, which |
155 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
78 | usually delivers "false") as it's sole argument when the given syscall has |
156 | perl, which usually delivers "false") as it's sole argument when the given |
79 | been executed asynchronously. |
157 | syscall has been executed asynchronously. |
80 | |
158 | |
81 | All functions that expect a filehandle will also accept a file descriptor. |
159 | All functions expecting a filehandle keep a copy of the filehandle |
|
|
160 | internally until the request has finished. |
82 | |
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 | |
83 | The filenames you pass to these routines I<must> be absolute. The reason |
165 | The pathnames you pass to these routines I<must> be absolute and |
84 | is that at the time the request is being executed, the current working |
166 | encoded in byte form. The reason for the former is that at the time the |
85 | directory could have changed. Alternatively, you can make sure that you |
167 | request is being executed, the current working directory could have |
|
|
168 | changed. Alternatively, you can make sure that you never change the |
86 | never change the current working directory. |
169 | current working directory. |
|
|
170 | |
|
|
171 | To encode pathnames to byte form, either make sure you either: a) |
|
|
172 | always pass in filenames you got from outside (command line, readdir |
|
|
173 | etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
|
|
174 | your pathnames to the locale (or other) encoding in effect in the user |
|
|
175 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
|
|
176 | use something else. |
87 | |
177 | |
88 | =over 4 |
178 | =over 4 |
89 | |
179 | |
|
|
180 | =item $prev_pri = aioreq_pri [$pri] |
|
|
181 | |
|
|
182 | Returns the priority value that would be used for the next request and, if |
|
|
183 | C<$pri> is given, sets the priority for the next aio request. |
|
|
184 | |
|
|
185 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
|
|
186 | and C<4>, respectively. Requests with higher priority will be serviced |
|
|
187 | first. |
|
|
188 | |
|
|
189 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
|
|
190 | functions. |
|
|
191 | |
|
|
192 | Example: open a file with low priority, then read something from it with |
|
|
193 | higher priority so the read request is serviced before other low priority |
|
|
194 | open requests (potentially spamming the cache): |
|
|
195 | |
|
|
196 | aioreq_pri -3; |
|
|
197 | aio_open ..., sub { |
|
|
198 | return unless $_[0]; |
|
|
199 | |
|
|
200 | aioreq_pri -2; |
|
|
201 | aio_read $_[0], ..., sub { |
|
|
202 | ... |
|
|
203 | }; |
|
|
204 | }; |
|
|
205 | |
|
|
206 | =item aioreq_nice $pri_adjust |
|
|
207 | |
|
|
208 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
|
209 | priority, so effects are cumulative. |
|
|
210 | |
90 | =item aio_open $pathname, $flags, $mode, $callback |
211 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
91 | |
212 | |
92 | Asynchronously open or create a file and call the callback with a newly |
213 | Asynchronously open or create a file and call the callback with a newly |
93 | created filehandle for the file. |
214 | created filehandle for the file. |
94 | |
215 | |
95 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
216 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
96 | for an explanation. |
217 | for an explanation. |
97 | |
218 | |
98 | The C<$mode> argument is a bitmask. See the C<Fcntl> module for a |
219 | The C<$flags> argument is a bitmask. See the C<Fcntl> module for a |
99 | list. They are the same as used in C<sysopen>. |
220 | list. They are the same as used by C<sysopen>. |
|
|
221 | |
|
|
222 | Likewise, C<$mode> specifies the mode of the newly created file, if it |
|
|
223 | didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, |
|
|
224 | except that it is mandatory (i.e. use C<0> if you don't create new files, |
|
|
225 | and C<0666> or C<0777> if you do). |
100 | |
226 | |
101 | Example: |
227 | Example: |
102 | |
228 | |
103 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
229 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
104 | if ($_[0]) { |
230 | if ($_[0]) { |
… | |
… | |
107 | } else { |
233 | } else { |
108 | die "open failed: $!\n"; |
234 | die "open failed: $!\n"; |
109 | } |
235 | } |
110 | }; |
236 | }; |
111 | |
237 | |
112 | =item aio_close $fh, $callback |
238 | =item aio_close $fh, $callback->($status) |
113 | |
239 | |
114 | Asynchronously close a file and call the callback with the result |
240 | Asynchronously close a file and call the callback with the result |
115 | code. I<WARNING:> although accepted, you should not pass in a perl |
241 | 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 |
242 | filehandle here, as perl will likely close the file descriptor another |
117 | the filehandle is destroyed. Normally, you can safely call perls C<close> |
243 | time when the filehandle is destroyed. Normally, you can safely call perls |
118 | or just let filehandles go out of scope. |
244 | C<close> or just let filehandles go out of scope. |
119 | |
245 | |
|
|
246 | This is supposed to be a bug in the API, so that might change. It's |
|
|
247 | therefore best to avoid this function. |
|
|
248 | |
120 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
249 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
121 | |
250 | |
122 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
251 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
123 | |
252 | |
124 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
253 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
125 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
254 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
126 | callback without the actual number of bytes read (or -1 on error, just |
255 | callback without the actual number of bytes read (or -1 on error, just |
127 | like the syscall). |
256 | like the syscall). |
128 | |
257 | |
|
|
258 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
|
|
259 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
|
|
260 | necessary/optional hardware is installed). |
|
|
261 | |
129 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at |
262 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
130 | offset C<0> within the scalar: |
263 | offset C<0> within the scalar: |
131 | |
264 | |
132 | aio_read $fh, 7, 15, $buffer, 0, sub { |
265 | aio_read $fh, 7, 15, $buffer, 0, sub { |
133 | $_[0] >= 0 or die "read error: $!"; |
266 | $_[0] > 0 or die "read error: $!"; |
134 | print "read <$buffer>\n"; |
267 | print "read $_[0] bytes: <$buffer>\n"; |
135 | }; |
268 | }; |
136 | |
269 | |
|
|
270 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
|
|
271 | |
|
|
272 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
|
|
273 | reading at byte offset C<$in_offset>, and starts writing at the current |
|
|
274 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
|
|
275 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
|
|
276 | other. |
|
|
277 | |
|
|
278 | This call tries to make use of a native C<sendfile> syscall to provide |
|
|
279 | zero-copy operation. For this to work, C<$out_fh> should refer to a |
|
|
280 | socket, and C<$in_fh> should refer to mmap'able file. |
|
|
281 | |
|
|
282 | If the native sendfile call fails or is not implemented, it will be |
|
|
283 | emulated, so you can call C<aio_sendfile> on any type of filehandle |
|
|
284 | regardless of the limitations of the operating system. |
|
|
285 | |
|
|
286 | Please note, however, that C<aio_sendfile> can read more bytes from |
|
|
287 | C<$in_fh> than are written, and there is no way to find out how many |
|
|
288 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
|
|
289 | provides the number of bytes written to C<$out_fh>. Only if the result |
|
|
290 | value equals C<$length> one can assume that C<$length> bytes have been |
|
|
291 | read. |
|
|
292 | |
137 | =item aio_readahead $fh,$offset,$length, $callback |
293 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
138 | |
294 | |
139 | Asynchronously reads the specified byte range into the page cache, using |
|
|
140 | the C<readahead> syscall. If that syscall doesn't exist the status will be |
|
|
141 | C<-1> and C<$!> is set to ENOSYS. |
|
|
142 | |
|
|
143 | readahead() populates the page cache with data from a file so that |
295 | C<aio_readahead> populates the page cache with data from a file so that |
144 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
296 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
145 | argument specifies the starting point from which data is to be read and |
297 | argument specifies the starting point from which data is to be read and |
146 | C<$length> specifies the number of bytes to be read. I/O is performed in |
298 | C<$length> specifies the number of bytes to be read. I/O is performed in |
147 | whole pages, so that offset is effectively rounded down to a page boundary |
299 | whole pages, so that offset is effectively rounded down to a page boundary |
148 | and bytes are read up to the next page boundary greater than or equal to |
300 | and bytes are read up to the next page boundary greater than or equal to |
149 | (off-set+length). aio_readahead() does not read beyond the end of the |
301 | (off-set+length). C<aio_readahead> does not read beyond the end of the |
150 | file. The current file offset of the file is left unchanged. |
302 | file. The current file offset of the file is left unchanged. |
151 | |
303 | |
|
|
304 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
|
|
305 | emulated by simply reading the data, which would have a similar effect. |
|
|
306 | |
152 | =item aio_stat $fh_or_path, $callback |
307 | =item aio_stat $fh_or_path, $callback->($status) |
153 | |
308 | |
154 | =item aio_lstat $fh, $callback |
309 | =item aio_lstat $fh, $callback->($status) |
155 | |
310 | |
156 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
311 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
157 | be called after the stat and the results will be available using C<stat _> |
312 | be called after the stat and the results will be available using C<stat _> |
158 | or C<-s _> etc... |
313 | or C<-s _> etc... |
159 | |
314 | |
… | |
… | |
169 | aio_stat "/etc/passwd", sub { |
324 | aio_stat "/etc/passwd", sub { |
170 | $_[0] and die "stat failed: $!"; |
325 | $_[0] and die "stat failed: $!"; |
171 | print "size is ", -s _, "\n"; |
326 | print "size is ", -s _, "\n"; |
172 | }; |
327 | }; |
173 | |
328 | |
174 | =item aio_unlink $pathname, $callback |
329 | =item aio_unlink $pathname, $callback->($status) |
175 | |
330 | |
176 | Asynchronously unlink (delete) a file and call the callback with the |
331 | Asynchronously unlink (delete) a file and call the callback with the |
177 | result code. |
332 | result code. |
178 | |
333 | |
|
|
334 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
|
|
335 | |
|
|
336 | Asynchronously create a device node (or fifo). See mknod(2): the only |
|
|
337 | portable value for C<$mode> is C<S_IFIFO> ored with permissions, and C<0> |
|
|
338 | for C<$dev>. |
|
|
339 | |
|
|
340 | =item aio_link $srcpath, $dstpath, $callback->($status) |
|
|
341 | |
|
|
342 | Asynchronously create a new link to the existing object at C<$srcpath> at |
|
|
343 | the path C<$dstpath> and call the callback with the result code. |
|
|
344 | |
|
|
345 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
346 | |
|
|
347 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
|
|
348 | the path C<$dstpath> and call the callback with the result code. |
|
|
349 | |
|
|
350 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
351 | |
|
|
352 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
|
|
353 | rename(2) and call the callback with the result code. |
|
|
354 | |
|
|
355 | =item aio_rmdir $pathname, $callback->($status) |
|
|
356 | |
|
|
357 | Asynchronously rmdir (delete) a directory and call the callback with the |
|
|
358 | result code. |
|
|
359 | |
|
|
360 | =item aio_readdir $pathname, $callback->($entries) |
|
|
361 | |
|
|
362 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
|
|
363 | directory (i.e. opendir + readdir + closedir). The entries will not be |
|
|
364 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
|
|
365 | |
|
|
366 | The callback a single argument which is either C<undef> or an array-ref |
|
|
367 | with the filenames. |
|
|
368 | |
|
|
369 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
370 | |
|
|
371 | Try to copy the I<file> (directories not supported as either source or |
|
|
372 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
373 | the C<0> (error) or C<-1> ok. |
|
|
374 | |
|
|
375 | This is a composite request that it creates the destination file with |
|
|
376 | mode 0200 and copies the contents of the source file into it using |
|
|
377 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
|
|
378 | uid/gid, in that order. |
|
|
379 | |
|
|
380 | If an error occurs, the partial destination file will be unlinked, if |
|
|
381 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
382 | errors are being ignored. |
|
|
383 | |
|
|
384 | =cut |
|
|
385 | |
|
|
386 | sub aio_copy($$;$) { |
|
|
387 | my ($src, $dst, $cb) = @_; |
|
|
388 | |
|
|
389 | my $pri = aioreq_pri; |
|
|
390 | my $grp = aio_group $cb; |
|
|
391 | |
|
|
392 | aioreq_pri $pri; |
|
|
393 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
394 | if (my $src_fh = $_[0]) { |
|
|
395 | my @stat = stat $src_fh; |
|
|
396 | |
|
|
397 | aioreq_pri $pri; |
|
|
398 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
399 | if (my $dst_fh = $_[0]) { |
|
|
400 | aioreq_pri $pri; |
|
|
401 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
402 | if ($_[0] == $stat[7]) { |
|
|
403 | $grp->result (0); |
|
|
404 | close $src_fh; |
|
|
405 | |
|
|
406 | # those should not normally block. should. should. |
|
|
407 | utime $stat[8], $stat[9], $dst; |
|
|
408 | chmod $stat[2] & 07777, $dst_fh; |
|
|
409 | chown $stat[4], $stat[5], $dst_fh; |
|
|
410 | close $dst_fh; |
|
|
411 | } else { |
|
|
412 | $grp->result (-1); |
|
|
413 | close $src_fh; |
|
|
414 | close $dst_fh; |
|
|
415 | |
|
|
416 | aioreq $pri; |
|
|
417 | add $grp aio_unlink $dst; |
|
|
418 | } |
|
|
419 | }; |
|
|
420 | } else { |
|
|
421 | $grp->result (-1); |
|
|
422 | } |
|
|
423 | }, |
|
|
424 | |
|
|
425 | } else { |
|
|
426 | $grp->result (-1); |
|
|
427 | } |
|
|
428 | }; |
|
|
429 | |
|
|
430 | $grp |
|
|
431 | } |
|
|
432 | |
|
|
433 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
434 | |
|
|
435 | Try to move the I<file> (directories not supported as either source or |
|
|
436 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
437 | the C<0> (error) or C<-1> ok. |
|
|
438 | |
|
|
439 | This is a composite request that tries to rename(2) the file first. If |
|
|
440 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
441 | that is successful, unlinking the C<$srcpath>. |
|
|
442 | |
|
|
443 | =cut |
|
|
444 | |
|
|
445 | sub aio_move($$;$) { |
|
|
446 | my ($src, $dst, $cb) = @_; |
|
|
447 | |
|
|
448 | my $pri = aioreq_pri; |
|
|
449 | my $grp = aio_group $cb; |
|
|
450 | |
|
|
451 | aioreq_pri $pri; |
|
|
452 | add $grp aio_rename $src, $dst, sub { |
|
|
453 | if ($_[0] && $! == EXDEV) { |
|
|
454 | aioreq_pri $pri; |
|
|
455 | add $grp aio_copy $src, $dst, sub { |
|
|
456 | $grp->result ($_[0]); |
|
|
457 | |
|
|
458 | if (!$_[0]) { |
|
|
459 | aioreq_pri $pri; |
|
|
460 | add $grp aio_unlink $src; |
|
|
461 | } |
|
|
462 | }; |
|
|
463 | } else { |
|
|
464 | $grp->result ($_[0]); |
|
|
465 | } |
|
|
466 | }; |
|
|
467 | |
|
|
468 | $grp |
|
|
469 | } |
|
|
470 | |
|
|
471 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
|
|
472 | |
|
|
473 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
|
|
474 | efficiently separate the entries of directory C<$path> into two sets of |
|
|
475 | names, directories you can recurse into (directories), and ones you cannot |
|
|
476 | recurse into (everything else, including symlinks to directories). |
|
|
477 | |
|
|
478 | C<aio_scandir> is a composite request that creates of many sub requests_ |
|
|
479 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
|
|
480 | this function generates. If it is C<< <= 0 >>, then a suitable default |
|
|
481 | will be chosen (currently 4). |
|
|
482 | |
|
|
483 | On error, the callback is called without arguments, otherwise it receives |
|
|
484 | two array-refs with path-relative entry names. |
|
|
485 | |
|
|
486 | Example: |
|
|
487 | |
|
|
488 | aio_scandir $dir, 0, sub { |
|
|
489 | my ($dirs, $nondirs) = @_; |
|
|
490 | print "real directories: @$dirs\n"; |
|
|
491 | print "everything else: @$nondirs\n"; |
|
|
492 | }; |
|
|
493 | |
|
|
494 | Implementation notes. |
|
|
495 | |
|
|
496 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
|
|
497 | |
|
|
498 | After reading the directory, the modification time, size etc. of the |
|
|
499 | directory before and after the readdir is checked, and if they match (and |
|
|
500 | isn't the current time), the link count will be used to decide how many |
|
|
501 | entries are directories (if >= 2). Otherwise, no knowledge of the number |
|
|
502 | of subdirectories will be assumed. |
|
|
503 | |
|
|
504 | Then entries will be sorted into likely directories (everything without |
|
|
505 | a non-initial dot currently) and likely non-directories (everything |
|
|
506 | else). Then every entry plus an appended C</.> will be C<stat>'ed, |
|
|
507 | likely directories first. If that succeeds, it assumes that the entry |
|
|
508 | is a directory or a symlink to directory (which will be checked |
|
|
509 | seperately). This is often faster than stat'ing the entry itself because |
|
|
510 | filesystems might detect the type of the entry without reading the inode |
|
|
511 | data (e.g. ext2fs filetype feature). |
|
|
512 | |
|
|
513 | If the known number of directories (link count - 2) has been reached, the |
|
|
514 | rest of the entries is assumed to be non-directories. |
|
|
515 | |
|
|
516 | This only works with certainty on POSIX (= UNIX) filesystems, which |
|
|
517 | fortunately are the vast majority of filesystems around. |
|
|
518 | |
|
|
519 | It will also likely work on non-POSIX filesystems with reduced efficiency |
|
|
520 | as those tend to return 0 or 1 as link counts, which disables the |
|
|
521 | directory counting heuristic. |
|
|
522 | |
|
|
523 | =cut |
|
|
524 | |
|
|
525 | sub aio_scandir($$$) { |
|
|
526 | my ($path, $maxreq, $cb) = @_; |
|
|
527 | |
|
|
528 | my $pri = aioreq_pri; |
|
|
529 | |
|
|
530 | my $grp = aio_group $cb; |
|
|
531 | |
|
|
532 | $maxreq = 4 if $maxreq <= 0; |
|
|
533 | |
|
|
534 | # stat once |
|
|
535 | aioreq_pri $pri; |
|
|
536 | add $grp aio_stat $path, sub { |
|
|
537 | return $grp->result () if $_[0]; |
|
|
538 | my $now = time; |
|
|
539 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
540 | |
|
|
541 | # read the directory entries |
|
|
542 | aioreq_pri $pri; |
|
|
543 | add $grp aio_readdir $path, sub { |
|
|
544 | my $entries = shift |
|
|
545 | or return $grp->result (); |
|
|
546 | |
|
|
547 | # stat the dir another time |
|
|
548 | aioreq_pri $pri; |
|
|
549 | add $grp aio_stat $path, sub { |
|
|
550 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
|
|
551 | |
|
|
552 | my $ndirs; |
|
|
553 | |
|
|
554 | # take the slow route if anything looks fishy |
|
|
555 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
|
|
556 | $ndirs = -1; |
|
|
557 | } else { |
|
|
558 | # if nlink == 2, we are finished |
|
|
559 | # on non-posix-fs's, we rely on nlink < 2 |
|
|
560 | $ndirs = (stat _)[3] - 2 |
|
|
561 | or return $grp->result ([], $entries); |
|
|
562 | } |
|
|
563 | |
|
|
564 | # sort into likely dirs and likely nondirs |
|
|
565 | # dirs == files without ".", short entries first |
|
|
566 | $entries = [map $_->[0], |
|
|
567 | sort { $b->[1] cmp $a->[1] } |
|
|
568 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
|
|
569 | @$entries]; |
|
|
570 | |
|
|
571 | my (@dirs, @nondirs); |
|
|
572 | |
|
|
573 | my $statgrp = add $grp aio_group sub { |
|
|
574 | $grp->result (\@dirs, \@nondirs); |
|
|
575 | }; |
|
|
576 | |
|
|
577 | limit $statgrp $maxreq; |
|
|
578 | feed $statgrp sub { |
|
|
579 | return unless @$entries; |
|
|
580 | my $entry = pop @$entries; |
|
|
581 | |
|
|
582 | aioreq_pri $pri; |
|
|
583 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
584 | if ($_[0] < 0) { |
|
|
585 | push @nondirs, $entry; |
|
|
586 | } else { |
|
|
587 | # need to check for real directory |
|
|
588 | aioreq_pri $pri; |
|
|
589 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
590 | if (-d _) { |
|
|
591 | push @dirs, $entry; |
|
|
592 | |
|
|
593 | unless (--$ndirs) { |
|
|
594 | push @nondirs, @$entries; |
|
|
595 | feed $statgrp; |
|
|
596 | } |
|
|
597 | } else { |
|
|
598 | push @nondirs, $entry; |
|
|
599 | } |
|
|
600 | } |
|
|
601 | } |
|
|
602 | }; |
|
|
603 | }; |
|
|
604 | }; |
|
|
605 | }; |
|
|
606 | }; |
|
|
607 | |
|
|
608 | $grp |
|
|
609 | } |
|
|
610 | |
179 | =item aio_fsync $fh, $callback |
611 | =item aio_fsync $fh, $callback->($status) |
180 | |
612 | |
181 | Asynchronously call fsync on the given filehandle and call the callback |
613 | Asynchronously call fsync on the given filehandle and call the callback |
182 | with the fsync result code. |
614 | with the fsync result code. |
183 | |
615 | |
184 | =item aio_fdatasync $fh, $callback |
616 | =item aio_fdatasync $fh, $callback->($status) |
185 | |
617 | |
186 | Asynchronously call fdatasync on the given filehandle and call the |
618 | Asynchronously call fdatasync on the given filehandle and call the |
187 | callback with the fdatasync result code. |
619 | callback with the fdatasync result code. |
188 | |
620 | |
|
|
621 | If this call isn't available because your OS lacks it or it couldn't be |
|
|
622 | detected, it will be emulated by calling C<fsync> instead. |
|
|
623 | |
|
|
624 | =item aio_group $callback->(...) |
|
|
625 | |
|
|
626 | This is a very special aio request: Instead of doing something, it is a |
|
|
627 | container for other aio requests, which is useful if you want to bundle |
|
|
628 | many requests into a single, composite, request with a definite callback |
|
|
629 | and the ability to cancel the whole request with its subrequests. |
|
|
630 | |
|
|
631 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
632 | for more info. |
|
|
633 | |
|
|
634 | Example: |
|
|
635 | |
|
|
636 | my $grp = aio_group sub { |
|
|
637 | print "all stats done\n"; |
|
|
638 | }; |
|
|
639 | |
|
|
640 | add $grp |
|
|
641 | (aio_stat ...), |
|
|
642 | (aio_stat ...), |
|
|
643 | ...; |
|
|
644 | |
|
|
645 | =item aio_nop $callback->() |
|
|
646 | |
|
|
647 | This is a special request - it does nothing in itself and is only used for |
|
|
648 | side effects, such as when you want to add a dummy request to a group so |
|
|
649 | that finishing the requests in the group depends on executing the given |
|
|
650 | code. |
|
|
651 | |
|
|
652 | While this request does nothing, it still goes through the execution |
|
|
653 | phase and still requires a worker thread. Thus, the callback will not |
|
|
654 | be executed immediately but only after other requests in the queue have |
|
|
655 | entered their execution phase. This can be used to measure request |
|
|
656 | latency. |
|
|
657 | |
|
|
658 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
|
|
659 | |
|
|
660 | Mainly used for debugging and benchmarking, this aio request puts one of |
|
|
661 | the request workers to sleep for the given time. |
|
|
662 | |
|
|
663 | While it is theoretically handy to have simple I/O scheduling requests |
|
|
664 | like sleep and file handle readable/writable, the overhead this creates is |
|
|
665 | immense (it blocks a thread for a long time) so do not use this function |
|
|
666 | except to put your application under artificial I/O pressure. |
|
|
667 | |
189 | =back |
668 | =back |
190 | |
669 | |
|
|
670 | =head2 IO::AIO::REQ CLASS |
|
|
671 | |
|
|
672 | All non-aggregate C<aio_*> functions return an object of this class when |
|
|
673 | called in non-void context. |
|
|
674 | |
|
|
675 | =over 4 |
|
|
676 | |
|
|
677 | =item cancel $req |
|
|
678 | |
|
|
679 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
680 | when entering the B<execute> state and skipping calling the callback when |
|
|
681 | entering the the B<result> state, but will leave the request otherwise |
|
|
682 | untouched. That means that requests that currently execute will not be |
|
|
683 | stopped and resources held by the request will not be freed prematurely. |
|
|
684 | |
|
|
685 | =item cb $req $callback->(...) |
|
|
686 | |
|
|
687 | Replace (or simply set) the callback registered to the request. |
|
|
688 | |
|
|
689 | =back |
|
|
690 | |
|
|
691 | =head2 IO::AIO::GRP CLASS |
|
|
692 | |
|
|
693 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
694 | objects of this class, too. |
|
|
695 | |
|
|
696 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
697 | aio requests. |
|
|
698 | |
|
|
699 | You create one by calling the C<aio_group> constructing function with a |
|
|
700 | callback that will be called when all contained requests have entered the |
|
|
701 | C<done> state: |
|
|
702 | |
|
|
703 | my $grp = aio_group sub { |
|
|
704 | print "all requests are done\n"; |
|
|
705 | }; |
|
|
706 | |
|
|
707 | You add requests by calling the C<add> method with one or more |
|
|
708 | C<IO::AIO::REQ> objects: |
|
|
709 | |
|
|
710 | $grp->add (aio_unlink "..."); |
|
|
711 | |
|
|
712 | add $grp aio_stat "...", sub { |
|
|
713 | $_[0] or return $grp->result ("error"); |
|
|
714 | |
|
|
715 | # add another request dynamically, if first succeeded |
|
|
716 | add $grp aio_open "...", sub { |
|
|
717 | $grp->result ("ok"); |
|
|
718 | }; |
|
|
719 | }; |
|
|
720 | |
|
|
721 | This makes it very easy to create composite requests (see the source of |
|
|
722 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
723 | |
|
|
724 | =over 4 |
|
|
725 | |
|
|
726 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
727 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
728 | |
|
|
729 | =item * They can be canceled like any other request. Canceling will cancel not |
|
|
730 | only the request itself, but also all requests it contains. |
|
|
731 | |
|
|
732 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
733 | |
|
|
734 | =item * You must not add requests to a group from within the group callback (or |
|
|
735 | any later time). |
|
|
736 | |
|
|
737 | =back |
|
|
738 | |
|
|
739 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
740 | will finish very quickly. If they contain only requests that are in the |
|
|
741 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
742 | exist. |
|
|
743 | |
|
|
744 | That means after creating a group you have some time to add requests. And |
|
|
745 | in the callbacks of those requests, you can add further requests to the |
|
|
746 | group. And only when all those requests have finished will the the group |
|
|
747 | itself finish. |
|
|
748 | |
|
|
749 | =over 4 |
|
|
750 | |
|
|
751 | =item add $grp ... |
|
|
752 | |
|
|
753 | =item $grp->add (...) |
|
|
754 | |
|
|
755 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
|
|
756 | be added, including other groups, as long as you do not create circular |
|
|
757 | dependencies. |
|
|
758 | |
|
|
759 | Returns all its arguments. |
|
|
760 | |
|
|
761 | =item $grp->cancel_subs |
|
|
762 | |
|
|
763 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
764 | itself. Useful when you queued a lot of events but got a result early. |
|
|
765 | |
|
|
766 | =item $grp->result (...) |
|
|
767 | |
|
|
768 | Set the result value(s) that will be passed to the group callback when all |
|
|
769 | subrequests have finished and set thre groups errno to the current value |
|
|
770 | of errno (just like calling C<errno> without an error number). By default, |
|
|
771 | no argument will be passed and errno is zero. |
|
|
772 | |
|
|
773 | =item $grp->errno ([$errno]) |
|
|
774 | |
|
|
775 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
776 | when the argument is missing. |
|
|
777 | |
|
|
778 | Every aio request has an associated errno value that is restored when |
|
|
779 | the callback is invoked. This method lets you change this value from its |
|
|
780 | default (0). |
|
|
781 | |
|
|
782 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
783 | before the call to C<result>, or call c<errno> after it. |
|
|
784 | |
|
|
785 | =item feed $grp $callback->($grp) |
|
|
786 | |
|
|
787 | Sets a feeder/generator on this group: every group can have an attached |
|
|
788 | generator that generates requests if idle. The idea behind this is that, |
|
|
789 | although you could just queue as many requests as you want in a group, |
|
|
790 | this might starve other requests for a potentially long time. For |
|
|
791 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
|
|
792 | requests, delaying any later requests for a long time. |
|
|
793 | |
|
|
794 | To avoid this, and allow incremental generation of requests, you can |
|
|
795 | instead a group and set a feeder on it that generates those requests. The |
|
|
796 | feed callback will be called whenever there are few enough (see C<limit>, |
|
|
797 | below) requests active in the group itself and is expected to queue more |
|
|
798 | requests. |
|
|
799 | |
|
|
800 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
|
|
801 | not impose any limits). |
|
|
802 | |
|
|
803 | If the feed does not queue more requests when called, it will be |
|
|
804 | automatically removed from the group. |
|
|
805 | |
|
|
806 | If the feed limit is C<0>, it will be set to C<2> automatically. |
|
|
807 | |
|
|
808 | Example: |
|
|
809 | |
|
|
810 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
811 | |
|
|
812 | my $grp = aio_group sub { print "finished\n" }; |
|
|
813 | limit $grp 4; |
|
|
814 | feed $grp sub { |
|
|
815 | my $file = pop @files |
|
|
816 | or return; |
|
|
817 | |
|
|
818 | add $grp aio_stat $file, sub { ... }; |
|
|
819 | }; |
|
|
820 | |
|
|
821 | =item limit $grp $num |
|
|
822 | |
|
|
823 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
824 | the group contains less than this many requests. |
|
|
825 | |
|
|
826 | Setting the limit to C<0> will pause the feeding process. |
|
|
827 | |
|
|
828 | =back |
|
|
829 | |
191 | =head2 SUPPORT FUNCTIONS |
830 | =head2 SUPPORT FUNCTIONS |
192 | |
831 | |
193 | =over 4 |
832 | =over 4 |
194 | |
833 | |
195 | =item $fileno = IO::AIO::poll_fileno |
834 | =item $fileno = IO::AIO::poll_fileno |
196 | |
835 | |
197 | Return the I<request result pipe filehandle>. This filehandle must be |
836 | Return the I<request result pipe file descriptor>. This filehandle must be |
198 | polled for reading by some mechanism outside this module (e.g. Event |
837 | polled for reading by some mechanism outside this module (e.g. Event or |
199 | or select, see below). If the pipe becomes readable you have to call |
838 | select, see below or the SYNOPSIS). If the pipe becomes readable you have |
200 | C<poll_cb> to check the results. |
839 | to call C<poll_cb> to check the results. |
201 | |
840 | |
202 | See C<poll_cb> for an example. |
841 | See C<poll_cb> for an example. |
203 | |
842 | |
204 | =item IO::AIO::poll_cb |
843 | =item IO::AIO::poll_cb |
205 | |
844 | |
206 | Process all outstanding events on the result pipe. You have to call this |
845 | Process all outstanding events on the result pipe. You have to call this |
207 | regularly. Returns the number of events processed. Returns immediately |
846 | regularly. Returns the number of events processed. Returns immediately |
208 | when no events are outstanding. |
847 | when no events are outstanding. |
209 | |
848 | |
210 | You can use Event to multiplex, e.g.: |
849 | If not all requests were processed for whatever reason, the filehandle |
|
|
850 | will still be ready when C<poll_cb> returns. |
|
|
851 | |
|
|
852 | Example: Install an Event watcher that automatically calls |
|
|
853 | IO::AIO::poll_cb with high priority: |
211 | |
854 | |
212 | Event->io (fd => IO::AIO::poll_fileno, |
855 | Event->io (fd => IO::AIO::poll_fileno, |
213 | poll => 'r', async => 1, |
856 | poll => 'r', async => 1, |
214 | cb => \&IO::AIO::poll_cb); |
857 | cb => \&IO::AIO::poll_cb); |
215 | |
858 | |
|
|
859 | =item IO::AIO::poll_some $max_requests |
|
|
860 | |
|
|
861 | Similar to C<poll_cb>, but only processes up to C<$max_requests> requests |
|
|
862 | at a time. |
|
|
863 | |
|
|
864 | Useful if you want to ensure some level of interactiveness when perl is |
|
|
865 | not fast enough to process all requests in time. |
|
|
866 | |
|
|
867 | Example: Install an Event watcher that automatically calls |
|
|
868 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
|
|
869 | program get the CPU sometimes even under high AIO load. |
|
|
870 | |
|
|
871 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
872 | poll => 'r', nice => 1, |
|
|
873 | cb => sub { IO::AIO::poll_some 256 }); |
|
|
874 | |
216 | =item IO::AIO::poll_wait |
875 | =item IO::AIO::poll_wait |
217 | |
876 | |
218 | Wait till the result filehandle becomes ready for reading (simply does a |
877 | 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 |
878 | C<select> on the filehandle. This is useful if you want to synchronously wait |
220 | for some requests to finish). |
879 | for some requests to finish). |
221 | |
880 | |
222 | See C<nreqs> for an example. |
881 | See C<nreqs> for an example. |
223 | |
882 | |
224 | =item IO::AIO::nreqs |
883 | =item IO::AIO::nreqs |
225 | |
884 | |
226 | Returns the number of requests currently outstanding. |
885 | Returns the number of requests currently in the ready, execute or pending |
|
|
886 | states (i.e. for which their callback has not been invoked yet). |
227 | |
887 | |
228 | Example: wait till there are no outstanding requests anymore: |
888 | Example: wait till there are no outstanding requests anymore: |
229 | |
889 | |
230 | IO::AIO::poll_wait, IO::AIO::poll_cb |
890 | IO::AIO::poll_wait, IO::AIO::poll_cb |
231 | while IO::AIO::nreqs; |
891 | while IO::AIO::nreqs; |
232 | |
892 | |
|
|
893 | =item IO::AIO::nready |
|
|
894 | |
|
|
895 | Returns the number of requests currently in the ready state (not yet |
|
|
896 | executed). |
|
|
897 | |
|
|
898 | =item IO::AIO::npending |
|
|
899 | |
|
|
900 | Returns the number of requests currently in the pending state (executed, |
|
|
901 | but not yet processed by poll_cb). |
|
|
902 | |
|
|
903 | =item IO::AIO::flush |
|
|
904 | |
|
|
905 | Wait till all outstanding AIO requests have been handled. |
|
|
906 | |
|
|
907 | Strictly equivalent to: |
|
|
908 | |
|
|
909 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
910 | while IO::AIO::nreqs; |
|
|
911 | |
|
|
912 | =item IO::AIO::poll |
|
|
913 | |
|
|
914 | Waits until some requests have been handled. |
|
|
915 | |
|
|
916 | Strictly equivalent to: |
|
|
917 | |
|
|
918 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
919 | if IO::AIO::nreqs; |
|
|
920 | |
233 | =item IO::AIO::min_parallel $nthreads |
921 | =item IO::AIO::min_parallel $nthreads |
234 | |
922 | |
235 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
923 | Set the minimum number of AIO threads to C<$nthreads>. The current |
236 | C<1>, which means a single asynchronous operation can be done at one time |
924 | default is C<8>, which means eight asynchronous operations can execute |
237 | (the number of outstanding operations, however, is unlimited). |
925 | concurrently at any one time (the number of outstanding requests, |
|
|
926 | however, is unlimited). |
238 | |
927 | |
|
|
928 | IO::AIO starts threads only on demand, when an AIO request is queued and |
|
|
929 | no free thread exists. |
|
|
930 | |
239 | It is recommended to keep the number of threads low, as some Linux |
931 | It is recommended to keep the number of threads relatively low, as some |
240 | kernel versions will scale negatively with the number of threads (higher |
932 | Linux kernel versions will scale negatively with the number of threads |
241 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
933 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
242 | threads should be fine. |
934 | versions, 4-32 threads should be fine. |
243 | |
935 | |
244 | Under normal circumstances you don't need to call this function, as this |
936 | Under most circumstances you don't need to call this function, as the |
245 | module automatically starts some threads (the exact number might change, |
937 | module selects a default that is suitable for low to moderate load. |
246 | and is currently 4). |
|
|
247 | |
938 | |
248 | =item IO::AIO::max_parallel $nthreads |
939 | =item IO::AIO::max_parallel $nthreads |
249 | |
940 | |
250 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
941 | Sets the maximum number of AIO threads to C<$nthreads>. If more than the |
251 | the specified number of threads are currently running, kill them. This |
942 | specified number of threads are currently running, this function kills |
252 | function blocks until the limit is reached. |
943 | them. This function blocks until the limit is reached. |
|
|
944 | |
|
|
945 | While C<$nthreads> are zero, aio requests get queued but not executed |
|
|
946 | until the number of threads has been increased again. |
253 | |
947 | |
254 | This module automatically runs C<max_parallel 0> at program end, to ensure |
948 | 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. |
949 | that all threads are killed and that there are no outstanding requests. |
256 | |
950 | |
257 | Under normal circumstances you don't need to call this function. |
951 | Under normal circumstances you don't need to call this function. |
258 | |
952 | |
259 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
953 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
|
|
954 | |
|
|
955 | This is a very bad function to use in interactive programs because it |
|
|
956 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
957 | use an C<aio_group> together with a feed callback. |
260 | |
958 | |
261 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
959 | 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 |
960 | to queue up more than this number of requests, the next call to the |
263 | some requests have been handled. |
961 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
962 | function will block until the limit is no longer exceeded. |
264 | |
963 | |
265 | The default is very large, so normally there is no practical limit. If you |
964 | The default value is very large, so there is no practical limit on the |
266 | queue up many requests in a loop it it often improves speed if you set |
965 | number of outstanding requests. |
267 | this to a relatively low number, such as C<100>. |
|
|
268 | |
966 | |
269 | Under normal circumstances you don't need to call this function. |
967 | You can still queue as many requests as you want. Therefore, |
|
|
968 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
|
|
969 | as a stop gap to shield against fatal memory overflow (with large values). |
270 | |
970 | |
271 | =back |
971 | =back |
272 | |
972 | |
273 | =cut |
973 | =cut |
274 | |
974 | |
275 | # support function to convert a fd into a perl filehandle |
975 | # support function to convert a fd into a perl filehandle |
276 | sub _fd2fh { |
976 | sub _fd2fh { |
277 | return undef if $_[0] < 0; |
977 | return undef if $_[0] < 0; |
278 | |
978 | |
279 | # try to be perl5.6-compatible |
979 | # try to generate nice filehandles |
280 | local *AIO_FH; |
980 | my $sym = "IO::AIO::fd#$_[0]"; |
281 | open AIO_FH, "+<&=$_[0]" |
981 | local *$sym; |
|
|
982 | |
|
|
983 | open *$sym, "+<&=$_[0]" # usually works under any unix |
|
|
984 | or open *$sym, "<&=$_[0]" # cygwin needs this |
|
|
985 | or open *$sym, ">&=$_[0]" # or this |
282 | or return undef; |
986 | or return undef; |
283 | |
987 | |
284 | *AIO_FH |
988 | *$sym |
285 | } |
989 | } |
286 | |
990 | |
287 | min_parallel 4; |
991 | min_parallel 8; |
288 | |
992 | |
289 | END { |
993 | END { |
290 | max_parallel 0; |
994 | flush; |
291 | } |
995 | }; |
292 | |
996 | |
293 | 1; |
997 | 1; |
294 | |
998 | |
|
|
999 | =head2 FORK BEHAVIOUR |
|
|
1000 | |
|
|
1001 | This module should do "the right thing" when the process using it forks: |
|
|
1002 | |
|
|
1003 | Before the fork, IO::AIO enters a quiescent state where no requests |
|
|
1004 | can be added in other threads and no results will be processed. After |
|
|
1005 | the fork the parent simply leaves the quiescent state and continues |
|
|
1006 | request/result processing, while the child frees the request/result queue |
|
|
1007 | (so that the requests started before the fork will only be handled in the |
|
|
1008 | parent). Threads will be started on demand until the limit set in the |
|
|
1009 | parent process has been reached again. |
|
|
1010 | |
|
|
1011 | In short: the parent will, after a short pause, continue as if fork had |
|
|
1012 | not been called, while the child will act as if IO::AIO has not been used |
|
|
1013 | yet. |
|
|
1014 | |
|
|
1015 | =head2 MEMORY USAGE |
|
|
1016 | |
|
|
1017 | Per-request usage: |
|
|
1018 | |
|
|
1019 | Each aio request uses - depending on your architecture - around 100-200 |
|
|
1020 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
|
|
1021 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
|
|
1022 | scalars and other data passed into aio requests will also be locked and |
|
|
1023 | will consume memory till the request has entered the done state. |
|
|
1024 | |
|
|
1025 | This is now awfully much, so queuing lots of requests is not usually a |
|
|
1026 | problem. |
|
|
1027 | |
|
|
1028 | Per-thread usage: |
|
|
1029 | |
|
|
1030 | In the execution phase, some aio requests require more memory for |
|
|
1031 | temporary buffers, and each thread requires a stack and other data |
|
|
1032 | structures (usually around 16k-128k, depending on the OS). |
|
|
1033 | |
|
|
1034 | =head1 KNOWN BUGS |
|
|
1035 | |
|
|
1036 | Known bugs will be fixed in the next release. |
|
|
1037 | |
295 | =head1 SEE ALSO |
1038 | =head1 SEE ALSO |
296 | |
1039 | |
297 | L<Coro>, L<Linux::AIO>. |
1040 | L<Coro::AIO>. |
298 | |
1041 | |
299 | =head1 AUTHOR |
1042 | =head1 AUTHOR |
300 | |
1043 | |
301 | Marc Lehmann <schmorp@schmorp.de> |
1044 | Marc Lehmann <schmorp@schmorp.de> |
302 | http://home.schmorp.de/ |
1045 | http://home.schmorp.de/ |