… | |
… | |
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 { |
9 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
10 | my ($fh) = @_; |
10 | my $fh = shift |
|
|
11 | or die "/etc/passwd: $!"; |
11 | ... |
12 | ... |
12 | }; |
13 | }; |
13 | |
14 | |
14 | aio_unlink "/tmp/file", sub { }; |
15 | aio_unlink "/tmp/file", sub { }; |
15 | |
16 | |
16 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
17 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
17 | $_[0] > 0 or die "read error: $!"; |
18 | $_[0] > 0 or die "read error: $!"; |
18 | }; |
19 | }; |
19 | |
20 | |
20 | # Event |
21 | # version 2+ has request and group objects |
21 | Event->io (fd => IO::AIO::poll_fileno, |
22 | use IO::AIO 2; |
22 | poll => 'r', |
|
|
23 | cb => \&IO::AIO::poll_cb); |
|
|
24 | |
23 | |
25 | # Glib/Gtk2 |
24 | aioreq_pri 4; # give next request a very high priority |
26 | add_watch Glib::IO IO::AIO::poll_fileno, |
25 | my $req = aio_unlink "/tmp/file", sub { }; |
27 | sub { IO::AIO::poll_cb, 1 }; |
26 | $req->cancel; # cancel request if still in queue |
28 | |
27 | |
29 | # Tk |
28 | my $grp = aio_group sub { print "all stats done\n" }; |
30 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
29 | add $grp aio_stat "..." for ...; |
31 | readable => \&IO::AIO::poll_cb); |
|
|
32 | |
|
|
33 | # Danga::Socket |
|
|
34 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
35 | \&IO::AIO::poll_cb); |
|
|
36 | |
|
|
37 | |
30 | |
38 | =head1 DESCRIPTION |
31 | =head1 DESCRIPTION |
39 | |
32 | |
40 | This module implements asynchronous I/O using whatever means your |
33 | This module implements asynchronous I/O using whatever means your |
41 | operating system supports. |
34 | operating system supports. It is implemented as an interface to C<libeio> |
|
|
35 | (L<http://software.schmorp.de/pkg/libeio.html>). |
42 | |
36 | |
|
|
37 | Asynchronous means that operations that can normally block your program |
|
|
38 | (e.g. reading from disk) will be done asynchronously: the operation |
|
|
39 | will still block, but you can do something else in the meantime. This |
|
|
40 | is extremely useful for programs that need to stay interactive even |
|
|
41 | when doing heavy I/O (GUI programs, high performance network servers |
|
|
42 | etc.), but can also be used to easily do operations in parallel that are |
|
|
43 | normally done sequentially, e.g. stat'ing many files, which is much faster |
|
|
44 | on a RAID volume or over NFS when you do a number of stat operations |
|
|
45 | concurrently. |
|
|
46 | |
|
|
47 | While most of this works on all types of file descriptors (for |
|
|
48 | example sockets), using these functions on file descriptors that |
|
|
49 | support nonblocking operation (again, sockets, pipes etc.) is |
|
|
50 | very inefficient. Use an event loop for that (such as the L<EV> |
|
|
51 | module): IO::AIO will naturally fit into such an event loop itself. |
|
|
52 | |
43 | Currently, a number of threads are started that execute your read/writes |
53 | 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 |
54 | 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 |
55 | 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 |
56 | 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 |
57 | functions available on many operating systems. However, they are often |
48 | not well-supported (Linux doesn't allow them on normal files currently, |
58 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
49 | for example), and they would only support aio_read and aio_write, so the |
59 | files currently, for example), and they would only support aio_read and |
50 | remaining functionality would have to be implemented using threads anyway. |
60 | aio_write, so the remaining functionality would have to be implemented |
|
|
61 | using threads anyway. |
51 | |
62 | |
52 | Although the module will work with in the presence of other threads, it is |
63 | Although the module will work in the presence of other (Perl-) threads, |
53 | currently not reentrant, so use appropriate locking yourself. |
64 | it is currently not reentrant in any way, so use appropriate locking |
|
|
65 | yourself, always call C<poll_cb> from within the same thread, or never |
|
|
66 | call C<poll_cb> (or other C<aio_> functions) recursively. |
|
|
67 | |
|
|
68 | =head2 EXAMPLE |
|
|
69 | |
|
|
70 | This is a simple example that uses the EV module and loads |
|
|
71 | F</etc/passwd> asynchronously: |
|
|
72 | |
|
|
73 | use Fcntl; |
|
|
74 | use EV; |
|
|
75 | use IO::AIO; |
|
|
76 | |
|
|
77 | # register the IO::AIO callback with EV |
|
|
78 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
79 | |
|
|
80 | # queue the request to open /etc/passwd |
|
|
81 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
|
|
82 | my $fh = shift |
|
|
83 | or die "error while opening: $!"; |
|
|
84 | |
|
|
85 | # stat'ing filehandles is generally non-blocking |
|
|
86 | my $size = -s $fh; |
|
|
87 | |
|
|
88 | # queue a request to read the file |
|
|
89 | my $contents; |
|
|
90 | aio_read $fh, 0, $size, $contents, 0, sub { |
|
|
91 | $_[0] == $size |
|
|
92 | or die "short read: $!"; |
|
|
93 | |
|
|
94 | close $fh; |
|
|
95 | |
|
|
96 | # file contents now in $contents |
|
|
97 | print $contents; |
|
|
98 | |
|
|
99 | # exit event loop and program |
|
|
100 | EV::unloop; |
|
|
101 | }; |
|
|
102 | }; |
|
|
103 | |
|
|
104 | # possibly queue up other requests, or open GUI windows, |
|
|
105 | # check for sockets etc. etc. |
|
|
106 | |
|
|
107 | # process events as long as there are some: |
|
|
108 | EV::loop; |
|
|
109 | |
|
|
110 | =head1 REQUEST ANATOMY AND LIFETIME |
|
|
111 | |
|
|
112 | Every C<aio_*> function creates a request. which is a C data structure not |
|
|
113 | directly visible to Perl. |
|
|
114 | |
|
|
115 | If called in non-void context, every request function returns a Perl |
|
|
116 | object representing the request. In void context, nothing is returned, |
|
|
117 | which saves a bit of memory. |
|
|
118 | |
|
|
119 | The perl object is a fairly standard ref-to-hash object. The hash contents |
|
|
120 | are not used by IO::AIO so you are free to store anything you like in it. |
|
|
121 | |
|
|
122 | During their existance, aio requests travel through the following states, |
|
|
123 | in order: |
|
|
124 | |
|
|
125 | =over 4 |
|
|
126 | |
|
|
127 | =item ready |
|
|
128 | |
|
|
129 | Immediately after a request is created it is put into the ready state, |
|
|
130 | waiting for a thread to execute it. |
|
|
131 | |
|
|
132 | =item execute |
|
|
133 | |
|
|
134 | A thread has accepted the request for processing and is currently |
|
|
135 | executing it (e.g. blocking in read). |
|
|
136 | |
|
|
137 | =item pending |
|
|
138 | |
|
|
139 | The request has been executed and is waiting for result processing. |
|
|
140 | |
|
|
141 | While request submission and execution is fully asynchronous, result |
|
|
142 | processing is not and relies on the perl interpreter calling C<poll_cb> |
|
|
143 | (or another function with the same effect). |
|
|
144 | |
|
|
145 | =item result |
|
|
146 | |
|
|
147 | The request results are processed synchronously by C<poll_cb>. |
|
|
148 | |
|
|
149 | The C<poll_cb> function will process all outstanding aio requests by |
|
|
150 | calling their callbacks, freeing memory associated with them and managing |
|
|
151 | any groups they are contained in. |
|
|
152 | |
|
|
153 | =item done |
|
|
154 | |
|
|
155 | Request has reached the end of its lifetime and holds no resources anymore |
|
|
156 | (except possibly for the Perl object, but its connection to the actual |
|
|
157 | aio request is severed and calling its methods will either do nothing or |
|
|
158 | result in a runtime error). |
|
|
159 | |
|
|
160 | =back |
54 | |
161 | |
55 | =cut |
162 | =cut |
56 | |
163 | |
57 | package IO::AIO; |
164 | package IO::AIO; |
58 | |
165 | |
|
|
166 | use Carp (); |
|
|
167 | |
|
|
168 | use common::sense; |
|
|
169 | |
59 | use base 'Exporter'; |
170 | use base 'Exporter'; |
60 | |
171 | |
61 | use Fcntl (); |
|
|
62 | |
|
|
63 | BEGIN { |
172 | BEGIN { |
64 | $VERSION = 0.3; |
173 | our $VERSION = '4.0'; |
65 | |
174 | |
66 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
175 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close |
67 | aio_fsync aio_fdatasync aio_readahead); |
176 | aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx |
68 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
177 | aio_scandir aio_symlink aio_readlink aio_realpath aio_sync |
|
|
178 | aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate |
|
|
179 | aio_pathsync aio_readahead |
|
|
180 | aio_rename aio_link aio_move aio_copy aio_group |
|
|
181 | aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown |
|
|
182 | aio_chmod aio_utime aio_truncate |
|
|
183 | aio_msync aio_mtouch aio_mlock aio_mlockall |
|
|
184 | aio_statvfs |
|
|
185 | aio_wd); |
|
|
186 | |
|
|
187 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
|
|
188 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
|
|
189 | min_parallel max_parallel max_idle idle_timeout |
|
|
190 | nreqs nready npending nthreads |
|
|
191 | max_poll_time max_poll_reqs |
|
|
192 | sendfile fadvise madvise |
|
|
193 | mmap munmap munlock munlockall); |
|
|
194 | |
|
|
195 | push @AIO_REQ, qw(aio_busy); # not exported |
|
|
196 | |
|
|
197 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
69 | |
198 | |
70 | require XSLoader; |
199 | require XSLoader; |
71 | XSLoader::load IO::AIO, $VERSION; |
200 | XSLoader::load ("IO::AIO", $VERSION); |
72 | } |
201 | } |
73 | |
202 | |
74 | =head1 FUNCTIONS |
203 | =head1 FUNCTIONS |
75 | |
204 | |
|
|
205 | =head2 QUICK OVERVIEW |
|
|
206 | |
|
|
207 | This section simply lists the prototypes of the most important functions |
|
|
208 | for quick reference. See the following sections for function-by-function |
|
|
209 | documentation. |
|
|
210 | |
|
|
211 | aio_wd $pathname, $callback->($wd) |
|
|
212 | aio_open $pathname, $flags, $mode, $callback->($fh) |
|
|
213 | aio_close $fh, $callback->($status) |
|
|
214 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
|
|
215 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
|
|
216 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
|
|
217 | aio_readahead $fh,$offset,$length, $callback->($retval) |
|
|
218 | aio_stat $fh_or_path, $callback->($status) |
|
|
219 | aio_lstat $fh, $callback->($status) |
|
|
220 | aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
221 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
|
|
222 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
|
|
223 | aio_truncate $fh_or_path, $offset, $callback->($status) |
|
|
224 | aio_chmod $fh_or_path, $mode, $callback->($status) |
|
|
225 | aio_unlink $pathname, $callback->($status) |
|
|
226 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
|
|
227 | aio_link $srcpath, $dstpath, $callback->($status) |
|
|
228 | aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
229 | aio_readlink $pathname, $callback->($link) |
|
|
230 | aio_realpath $pathname, $callback->($link) |
|
|
231 | aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
232 | aio_mkdir $pathname, $mode, $callback->($status) |
|
|
233 | aio_rmdir $pathname, $callback->($status) |
|
|
234 | aio_readdir $pathname, $callback->($entries) |
|
|
235 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
236 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
|
|
237 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
238 | aio_load $pathname, $data, $callback->($status) |
|
|
239 | aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
240 | aio_move $srcpath, $dstpath, $callback->($status) |
|
|
241 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
|
|
242 | aio_rmtree $pathname, $callback->($status) |
|
|
243 | aio_sync $callback->($status) |
|
|
244 | aio_syncfs $fh, $callback->($status) |
|
|
245 | aio_fsync $fh, $callback->($status) |
|
|
246 | aio_fdatasync $fh, $callback->($status) |
|
|
247 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
248 | aio_pathsync $pathname, $callback->($status) |
|
|
249 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
250 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
251 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
252 | aio_mlockall $flags, $callback->($status) |
|
|
253 | aio_group $callback->(...) |
|
|
254 | aio_nop $callback->() |
|
|
255 | |
|
|
256 | $prev_pri = aioreq_pri [$pri] |
|
|
257 | aioreq_nice $pri_adjust |
|
|
258 | |
|
|
259 | IO::AIO::poll_wait |
|
|
260 | IO::AIO::poll_cb |
|
|
261 | IO::AIO::poll |
|
|
262 | IO::AIO::flush |
|
|
263 | IO::AIO::max_poll_reqs $nreqs |
|
|
264 | IO::AIO::max_poll_time $seconds |
|
|
265 | IO::AIO::min_parallel $nthreads |
|
|
266 | IO::AIO::max_parallel $nthreads |
|
|
267 | IO::AIO::max_idle $nthreads |
|
|
268 | IO::AIO::idle_timeout $seconds |
|
|
269 | IO::AIO::max_outstanding $maxreqs |
|
|
270 | IO::AIO::nreqs |
|
|
271 | IO::AIO::nready |
|
|
272 | IO::AIO::npending |
|
|
273 | |
|
|
274 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
275 | IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
276 | IO::AIO::madvise $scalar, $offset, $length, $advice |
|
|
277 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
|
|
278 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
279 | IO::AIO::munlockall |
|
|
280 | |
76 | =head2 AIO FUNCTIONS |
281 | =head2 AIO REQUEST FUNCTIONS |
77 | |
282 | |
78 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
283 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
79 | with the same name (sans C<aio_>). The arguments are similar or identical, |
284 | with the same name (sans C<aio_>). The arguments are similar or identical, |
80 | and they all accept an additional (and optional) C<$callback> argument |
285 | and they all accept an additional (and optional) C<$callback> argument |
81 | which must be a code reference. This code reference will get called with |
286 | which must be a code reference. This code reference will get called with |
82 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
287 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
83 | perl, which usually delivers "false") as it's sole argument when the given |
288 | perl, which usually delivers "false") as its sole argument after the given |
84 | syscall has been executed asynchronously. |
289 | syscall has been executed asynchronously. |
85 | |
290 | |
86 | All functions that expect a filehandle will also accept a file descriptor. |
291 | All functions expecting a filehandle keep a copy of the filehandle |
|
|
292 | internally until the request has finished. |
87 | |
293 | |
|
|
294 | All functions return request objects of type L<IO::AIO::REQ> that allow |
|
|
295 | further manipulation of those requests while they are in-flight. |
|
|
296 | |
88 | The filenames you pass to these routines I<must> be absolute. The reason |
297 | The pathnames you pass to these routines I<should> be absolute. The |
89 | is that at the time the request is being executed, the current working |
298 | reason for this is that at the time the request is being executed, the |
90 | directory could have changed. Alternatively, you can make sure that you |
299 | current working directory could have changed. Alternatively, you can make |
91 | never change the current working directory. |
300 | sure that you never change the current working directory anywhere in |
|
|
301 | the program and then use relative paths. Lastly, you can take advantage |
|
|
302 | of IO::AIOs working directory abstraction - see the description of the |
|
|
303 | C<IO::AIO::WD> class later in this document. |
|
|
304 | |
|
|
305 | To encode pathnames as octets, either make sure you either: a) always pass |
|
|
306 | in filenames you got from outside (command line, readdir etc.) without |
|
|
307 | tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
|
|
308 | your pathnames to the locale (or other) encoding in effect in the user |
|
|
309 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
|
|
310 | use something else to ensure your scalar has the correct contents. |
|
|
311 | |
|
|
312 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
|
|
313 | handles correctly whether it is set or not. |
92 | |
314 | |
93 | =over 4 |
315 | =over 4 |
94 | |
316 | |
|
|
317 | =item $prev_pri = aioreq_pri [$pri] |
|
|
318 | |
|
|
319 | Returns the priority value that would be used for the next request and, if |
|
|
320 | C<$pri> is given, sets the priority for the next aio request. |
|
|
321 | |
|
|
322 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
|
|
323 | and C<4>, respectively. Requests with higher priority will be serviced |
|
|
324 | first. |
|
|
325 | |
|
|
326 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
|
|
327 | functions. |
|
|
328 | |
|
|
329 | Example: open a file with low priority, then read something from it with |
|
|
330 | higher priority so the read request is serviced before other low priority |
|
|
331 | open requests (potentially spamming the cache): |
|
|
332 | |
|
|
333 | aioreq_pri -3; |
|
|
334 | aio_open ..., sub { |
|
|
335 | return unless $_[0]; |
|
|
336 | |
|
|
337 | aioreq_pri -2; |
|
|
338 | aio_read $_[0], ..., sub { |
|
|
339 | ... |
|
|
340 | }; |
|
|
341 | }; |
|
|
342 | |
|
|
343 | |
|
|
344 | =item aioreq_nice $pri_adjust |
|
|
345 | |
|
|
346 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
|
347 | priority, so the effect is cumulative. |
|
|
348 | |
|
|
349 | |
95 | =item aio_open $pathname, $flags, $mode, $callback |
350 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
96 | |
351 | |
97 | Asynchronously open or create a file and call the callback with a newly |
352 | Asynchronously open or create a file and call the callback with a newly |
98 | created filehandle for the file. |
353 | created filehandle for the file. |
99 | |
354 | |
100 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
355 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
101 | for an explanation. |
356 | for an explanation. |
102 | |
357 | |
103 | The C<$mode> argument is a bitmask. See the C<Fcntl> module for a |
358 | The C<$flags> argument is a bitmask. See the C<Fcntl> module for a |
104 | list. They are the same as used in C<sysopen>. |
359 | list. They are the same as used by C<sysopen>. |
|
|
360 | |
|
|
361 | Likewise, C<$mode> specifies the mode of the newly created file, if it |
|
|
362 | didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, |
|
|
363 | except that it is mandatory (i.e. use C<0> if you don't create new files, |
|
|
364 | and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified |
|
|
365 | by the umask in effect then the request is being executed, so better never |
|
|
366 | change the umask. |
105 | |
367 | |
106 | Example: |
368 | Example: |
107 | |
369 | |
108 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
370 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
109 | if ($_[0]) { |
371 | if ($_[0]) { |
110 | print "open successful, fh is $_[0]\n"; |
372 | print "open successful, fh is $_[0]\n"; |
111 | ... |
373 | ... |
112 | } else { |
374 | } else { |
113 | die "open failed: $!\n"; |
375 | die "open failed: $!\n"; |
114 | } |
376 | } |
115 | }; |
377 | }; |
116 | |
378 | |
|
|
379 | In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>, |
|
|
380 | C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the |
|
|
381 | following POSIX and non-POSIX constants are available (missing ones on |
|
|
382 | your system are, as usual, C<0>): |
|
|
383 | |
|
|
384 | C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, |
|
|
385 | C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, |
|
|
386 | C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. |
|
|
387 | |
|
|
388 | |
117 | =item aio_close $fh, $callback |
389 | =item aio_close $fh, $callback->($status) |
118 | |
390 | |
119 | Asynchronously close a file and call the callback with the result |
391 | Asynchronously close a file and call the callback with the result |
120 | code. I<WARNING:> although accepted, you should not pass in a perl |
392 | code. |
121 | filehandle here, as perl will likely close the file descriptor itself when |
|
|
122 | the filehandle is destroyed. Normally, you can safely call perls C<close> |
|
|
123 | or just let filehandles go out of scope. |
|
|
124 | |
393 | |
|
|
394 | Unfortunately, you can't do this to perl. Perl I<insists> very strongly on |
|
|
395 | closing the file descriptor associated with the filehandle itself. |
|
|
396 | |
|
|
397 | Therefore, C<aio_close> will not close the filehandle - instead it will |
|
|
398 | use dup2 to overwrite the file descriptor with the write-end of a pipe |
|
|
399 | (the pipe fd will be created on demand and will be cached). |
|
|
400 | |
|
|
401 | Or in other words: the file descriptor will be closed, but it will not be |
|
|
402 | free for reuse until the perl filehandle is closed. |
|
|
403 | |
|
|
404 | =cut |
|
|
405 | |
125 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
406 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
126 | |
407 | |
127 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
408 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
128 | |
409 | |
129 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
410 | Reads or writes C<$length> bytes from or to the specified C<$fh> and |
130 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
411 | C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> |
131 | callback without the actual number of bytes read (or -1 on error, just |
412 | and calls the callback without the actual number of bytes read (or -1 on |
132 | like the syscall). |
413 | error, just like the syscall). |
133 | |
414 | |
|
|
415 | C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to |
|
|
416 | offset plus the actual number of bytes read. |
|
|
417 | |
|
|
418 | If C<$offset> is undefined, then the current file descriptor offset will |
|
|
419 | be used (and updated), otherwise the file descriptor offset will not be |
|
|
420 | changed by these calls. |
|
|
421 | |
|
|
422 | If C<$length> is undefined in C<aio_write>, use the remaining length of |
|
|
423 | C<$data>. |
|
|
424 | |
|
|
425 | If C<$dataoffset> is less than zero, it will be counted from the end of |
|
|
426 | C<$data>. |
|
|
427 | |
|
|
428 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
|
|
429 | is outstanding. Modifying it can result in segfaults or World War III (if |
|
|
430 | the necessary/optional hardware is installed). |
|
|
431 | |
134 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at |
432 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
135 | offset C<0> within the scalar: |
433 | offset C<0> within the scalar: |
136 | |
434 | |
137 | aio_read $fh, 7, 15, $buffer, 0, sub { |
435 | aio_read $fh, 7, 15, $buffer, 0, sub { |
138 | $_[0] > 0 or die "read error: $!"; |
436 | $_[0] > 0 or die "read error: $!"; |
139 | print "read $_[0] bytes: <$buffer>\n"; |
437 | print "read $_[0] bytes: <$buffer>\n"; |
140 | }; |
438 | }; |
141 | |
439 | |
|
|
440 | |
|
|
441 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
|
|
442 | |
|
|
443 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
|
|
444 | reading at byte offset C<$in_offset>, and starts writing at the current |
|
|
445 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
|
|
446 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
|
|
447 | other. The same C<$in_fh> works fine though, as this function does not |
|
|
448 | move or use the file offset of C<$in_fh>. |
|
|
449 | |
|
|
450 | Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than |
|
|
451 | are written, and there is no way to find out how many more bytes have been |
|
|
452 | read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the |
|
|
453 | number of bytes written to C<$out_fh>. Only if the result value equals |
|
|
454 | C<$length> one can assume that C<$length> bytes have been read. |
|
|
455 | |
|
|
456 | Unlike with other C<aio_> functions, it makes a lot of sense to use |
|
|
457 | C<aio_sendfile> on non-blocking sockets, as long as one end (typically |
|
|
458 | the C<$in_fh>) is a file - the file I/O will then be asynchronous, while |
|
|
459 | the socket I/O will be non-blocking. Note, however, that you can run |
|
|
460 | into a trap where C<aio_sendfile> reads some data with readahead, then |
|
|
461 | fails to write all data, and when the socket is ready the next time, the |
|
|
462 | data in the cache is already lost, forcing C<aio_sendfile> to again hit |
|
|
463 | the disk. Explicit C<aio_read> + C<aio_write> let's you better control |
|
|
464 | resource usage. |
|
|
465 | |
|
|
466 | This call tries to make use of a native C<sendfile>-like syscall to |
|
|
467 | provide zero-copy operation. For this to work, C<$out_fh> should refer to |
|
|
468 | a socket, and C<$in_fh> should refer to an mmap'able file. |
|
|
469 | |
|
|
470 | If a native sendfile cannot be found or it fails with C<ENOSYS>, |
|
|
471 | C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or |
|
|
472 | C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any |
|
|
473 | type of filehandle regardless of the limitations of the operating system. |
|
|
474 | |
|
|
475 | As native sendfile syscalls (as practically any non-POSIX interface hacked |
|
|
476 | together in a hurry to improve benchmark numbers) tend to be rather buggy |
|
|
477 | on many systems, this implementation tries to work around some known bugs |
|
|
478 | in Linux and FreeBSD kernels (probably others, too), but that might fail, |
|
|
479 | so you really really should check the return value of C<aio_sendfile> - |
|
|
480 | fewre bytes than expected might have been transferred. |
|
|
481 | |
|
|
482 | |
142 | =item aio_readahead $fh,$offset,$length, $callback |
483 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
143 | |
484 | |
144 | Asynchronously reads the specified byte range into the page cache, using |
|
|
145 | the C<readahead> syscall. If that syscall doesn't exist the status will be |
|
|
146 | C<-1> and C<$!> is set to ENOSYS. |
|
|
147 | |
|
|
148 | readahead() populates the page cache with data from a file so that |
485 | C<aio_readahead> populates the page cache with data from a file so that |
149 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
486 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
150 | argument specifies the starting point from which data is to be read and |
487 | argument specifies the starting point from which data is to be read and |
151 | C<$length> specifies the number of bytes to be read. I/O is performed in |
488 | C<$length> specifies the number of bytes to be read. I/O is performed in |
152 | whole pages, so that offset is effectively rounded down to a page boundary |
489 | whole pages, so that offset is effectively rounded down to a page boundary |
153 | and bytes are read up to the next page boundary greater than or equal to |
490 | and bytes are read up to the next page boundary greater than or equal to |
154 | (off-set+length). aio_readahead() does not read beyond the end of the |
491 | (off-set+length). C<aio_readahead> does not read beyond the end of the |
155 | file. The current file offset of the file is left unchanged. |
492 | file. The current file offset of the file is left unchanged. |
156 | |
493 | |
|
|
494 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
|
|
495 | emulated by simply reading the data, which would have a similar effect. |
|
|
496 | |
|
|
497 | |
157 | =item aio_stat $fh_or_path, $callback |
498 | =item aio_stat $fh_or_path, $callback->($status) |
158 | |
499 | |
159 | =item aio_lstat $fh, $callback |
500 | =item aio_lstat $fh, $callback->($status) |
160 | |
501 | |
161 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
502 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
162 | be called after the stat and the results will be available using C<stat _> |
503 | be called after the stat and the results will be available using C<stat _> |
163 | or C<-s _> etc... |
504 | or C<-s _> etc... |
164 | |
505 | |
… | |
… | |
166 | for an explanation. |
507 | for an explanation. |
167 | |
508 | |
168 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
509 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
169 | error when stat'ing a large file, the results will be silently truncated |
510 | error when stat'ing a large file, the results will be silently truncated |
170 | unless perl itself is compiled with large file support. |
511 | unless perl itself is compiled with large file support. |
|
|
512 | |
|
|
513 | To help interpret the mode and dev/rdev stat values, IO::AIO offers the |
|
|
514 | following constants and functions (if not implemented, the constants will |
|
|
515 | be C<0> and the functions will either C<croak> or fall back on traditional |
|
|
516 | behaviour). |
|
|
517 | |
|
|
518 | C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, |
|
|
519 | C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, |
|
|
520 | C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. |
171 | |
521 | |
172 | Example: Print the length of F</etc/passwd>: |
522 | Example: Print the length of F</etc/passwd>: |
173 | |
523 | |
174 | aio_stat "/etc/passwd", sub { |
524 | aio_stat "/etc/passwd", sub { |
175 | $_[0] and die "stat failed: $!"; |
525 | $_[0] and die "stat failed: $!"; |
176 | print "size is ", -s _, "\n"; |
526 | print "size is ", -s _, "\n"; |
177 | }; |
527 | }; |
178 | |
528 | |
|
|
529 | |
|
|
530 | =item aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
531 | |
|
|
532 | Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on |
|
|
533 | whether a file handle or path was passed. |
|
|
534 | |
|
|
535 | On success, the callback is passed a hash reference with the following |
|
|
536 | members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>, |
|
|
537 | C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef> |
|
|
538 | is passed. |
|
|
539 | |
|
|
540 | The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and |
|
|
541 | C<ST_NOSUID>. |
|
|
542 | |
|
|
543 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
|
|
544 | their correct value when available, or to C<0> on systems that do |
|
|
545 | not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>, |
|
|
546 | C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>, |
|
|
547 | C<ST_NODIRATIME> and C<ST_RELATIME>. |
|
|
548 | |
|
|
549 | Example: stat C</wd> and dump out the data if successful. |
|
|
550 | |
|
|
551 | aio_statvfs "/wd", sub { |
|
|
552 | my $f = $_[0] |
|
|
553 | or die "statvfs: $!"; |
|
|
554 | |
|
|
555 | use Data::Dumper; |
|
|
556 | say Dumper $f; |
|
|
557 | }; |
|
|
558 | |
|
|
559 | # result: |
|
|
560 | { |
|
|
561 | bsize => 1024, |
|
|
562 | bfree => 4333064312, |
|
|
563 | blocks => 10253828096, |
|
|
564 | files => 2050765568, |
|
|
565 | flag => 4096, |
|
|
566 | favail => 2042092649, |
|
|
567 | bavail => 4333064312, |
|
|
568 | ffree => 2042092649, |
|
|
569 | namemax => 255, |
|
|
570 | frsize => 1024, |
|
|
571 | fsid => 1810 |
|
|
572 | } |
|
|
573 | |
|
|
574 | |
|
|
575 | =item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
|
|
576 | |
|
|
577 | Works like perl's C<utime> function (including the special case of $atime |
|
|
578 | and $mtime being undef). Fractional times are supported if the underlying |
|
|
579 | syscalls support them. |
|
|
580 | |
|
|
581 | When called with a pathname, uses utimes(2) if available, otherwise |
|
|
582 | utime(2). If called on a file descriptor, uses futimes(2) if available, |
|
|
583 | otherwise returns ENOSYS, so this is not portable. |
|
|
584 | |
|
|
585 | Examples: |
|
|
586 | |
|
|
587 | # set atime and mtime to current time (basically touch(1)): |
|
|
588 | aio_utime "path", undef, undef; |
|
|
589 | # set atime to current time and mtime to beginning of the epoch: |
|
|
590 | aio_utime "path", time, undef; # undef==0 |
|
|
591 | |
|
|
592 | |
|
|
593 | =item aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
|
|
594 | |
|
|
595 | Works like perl's C<chown> function, except that C<undef> for either $uid |
|
|
596 | or $gid is being interpreted as "do not change" (but -1 can also be used). |
|
|
597 | |
|
|
598 | Examples: |
|
|
599 | |
|
|
600 | # same as "chown root path" in the shell: |
|
|
601 | aio_chown "path", 0, -1; |
|
|
602 | # same as above: |
|
|
603 | aio_chown "path", 0, undef; |
|
|
604 | |
|
|
605 | |
|
|
606 | =item aio_truncate $fh_or_path, $offset, $callback->($status) |
|
|
607 | |
|
|
608 | Works like truncate(2) or ftruncate(2). |
|
|
609 | |
|
|
610 | |
|
|
611 | =item aio_chmod $fh_or_path, $mode, $callback->($status) |
|
|
612 | |
|
|
613 | Works like perl's C<chmod> function. |
|
|
614 | |
|
|
615 | |
179 | =item aio_unlink $pathname, $callback |
616 | =item aio_unlink $pathname, $callback->($status) |
180 | |
617 | |
181 | Asynchronously unlink (delete) a file and call the callback with the |
618 | Asynchronously unlink (delete) a file and call the callback with the |
182 | result code. |
619 | result code. |
183 | |
620 | |
|
|
621 | |
|
|
622 | =item aio_mknod $pathname, $mode, $dev, $callback->($status) |
|
|
623 | |
|
|
624 | [EXPERIMENTAL] |
|
|
625 | |
|
|
626 | Asynchronously create a device node (or fifo). See mknod(2). |
|
|
627 | |
|
|
628 | The only (POSIX-) portable way of calling this function is: |
|
|
629 | |
|
|
630 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
631 | |
|
|
632 | See C<aio_stat> for info about some potentially helpful extra constants |
|
|
633 | and functions. |
|
|
634 | |
|
|
635 | =item aio_link $srcpath, $dstpath, $callback->($status) |
|
|
636 | |
|
|
637 | Asynchronously create a new link to the existing object at C<$srcpath> at |
|
|
638 | the path C<$dstpath> and call the callback with the result code. |
|
|
639 | |
|
|
640 | |
|
|
641 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
642 | |
|
|
643 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
|
|
644 | the path C<$dstpath> and call the callback with the result code. |
|
|
645 | |
|
|
646 | |
|
|
647 | =item aio_readlink $pathname, $callback->($link) |
|
|
648 | |
|
|
649 | Asynchronously read the symlink specified by C<$path> and pass it to |
|
|
650 | the callback. If an error occurs, nothing or undef gets passed to the |
|
|
651 | callback. |
|
|
652 | |
|
|
653 | |
|
|
654 | =item aio_realpath $pathname, $callback->($path) |
|
|
655 | |
|
|
656 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
657 | C<$path>. The resulting path only consists of directories (Same as |
|
|
658 | L<Cwd::realpath>). |
|
|
659 | |
|
|
660 | This request can be used to get the absolute path of the current working |
|
|
661 | directory by passing it a path of F<.> (a single dot). |
|
|
662 | |
|
|
663 | |
|
|
664 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
665 | |
|
|
666 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
|
|
667 | rename(2) and call the callback with the result code. |
|
|
668 | |
|
|
669 | |
|
|
670 | =item aio_mkdir $pathname, $mode, $callback->($status) |
|
|
671 | |
|
|
672 | Asynchronously mkdir (create) a directory and call the callback with |
|
|
673 | the result code. C<$mode> will be modified by the umask at the time the |
|
|
674 | request is executed, so do not change your umask. |
|
|
675 | |
|
|
676 | |
|
|
677 | =item aio_rmdir $pathname, $callback->($status) |
|
|
678 | |
|
|
679 | Asynchronously rmdir (delete) a directory and call the callback with the |
|
|
680 | result code. |
|
|
681 | |
|
|
682 | |
|
|
683 | =item aio_readdir $pathname, $callback->($entries) |
|
|
684 | |
|
|
685 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
|
|
686 | directory (i.e. opendir + readdir + closedir). The entries will not be |
|
|
687 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
|
|
688 | |
|
|
689 | The callback is passed a single argument which is either C<undef> or an |
|
|
690 | array-ref with the filenames. |
|
|
691 | |
|
|
692 | |
|
|
693 | =item aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
694 | |
|
|
695 | Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to |
|
|
696 | tune behaviour and output format. In case of an error, C<$entries> will be |
|
|
697 | C<undef>. |
|
|
698 | |
|
|
699 | The flags are a combination of the following constants, ORed together (the |
|
|
700 | flags will also be passed to the callback, possibly modified): |
|
|
701 | |
|
|
702 | =over 4 |
|
|
703 | |
|
|
704 | =item IO::AIO::READDIR_DENTS |
|
|
705 | |
|
|
706 | When this flag is off, then the callback gets an arrayref consisting of |
|
|
707 | names only (as with C<aio_readdir>), otherwise it gets an arrayref with |
|
|
708 | C<[$name, $type, $inode]> arrayrefs, each describing a single directory |
|
|
709 | entry in more detail. |
|
|
710 | |
|
|
711 | C<$name> is the name of the entry. |
|
|
712 | |
|
|
713 | C<$type> is one of the C<IO::AIO::DT_xxx> constants: |
|
|
714 | |
|
|
715 | C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, |
|
|
716 | C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, |
|
|
717 | C<IO::AIO::DT_WHT>. |
|
|
718 | |
|
|
719 | C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to |
|
|
720 | know, you have to run stat yourself. Also, for speed reasons, the C<$type> |
|
|
721 | scalars are read-only: you can not modify them. |
|
|
722 | |
|
|
723 | C<$inode> is the inode number (which might not be exact on systems with 64 |
|
|
724 | bit inode numbers and 32 bit perls). This field has unspecified content on |
|
|
725 | systems that do not deliver the inode information. |
|
|
726 | |
|
|
727 | =item IO::AIO::READDIR_DIRS_FIRST |
|
|
728 | |
|
|
729 | When this flag is set, then the names will be returned in an order where |
|
|
730 | likely directories come first, in optimal stat order. This is useful when |
|
|
731 | you need to quickly find directories, or you want to find all directories |
|
|
732 | while avoiding to stat() each entry. |
|
|
733 | |
|
|
734 | If the system returns type information in readdir, then this is used |
|
|
735 | to find directories directly. Otherwise, likely directories are names |
|
|
736 | beginning with ".", or otherwise names with no dots, of which names with |
|
|
737 | short names are tried first. |
|
|
738 | |
|
|
739 | =item IO::AIO::READDIR_STAT_ORDER |
|
|
740 | |
|
|
741 | When this flag is set, then the names will be returned in an order |
|
|
742 | suitable for stat()'ing each one. That is, when you plan to stat() |
|
|
743 | all files in the given directory, then the returned order will likely |
|
|
744 | be fastest. |
|
|
745 | |
|
|
746 | If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then |
|
|
747 | the likely dirs come first, resulting in a less optimal stat order. |
|
|
748 | |
|
|
749 | =item IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
750 | |
|
|
751 | This flag should not be set when calling C<aio_readdirx>. Instead, it |
|
|
752 | is being set by C<aio_readdirx>, when any of the C<$type>'s found were |
|
|
753 | C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all |
|
|
754 | C<$type>'s are known, which can be used to speed up some algorithms. |
|
|
755 | |
|
|
756 | =back |
|
|
757 | |
|
|
758 | |
|
|
759 | =item aio_load $pathname, $data, $callback->($status) |
|
|
760 | |
|
|
761 | This is a composite request that tries to fully load the given file into |
|
|
762 | memory. Status is the same as with aio_read. |
|
|
763 | |
|
|
764 | =cut |
|
|
765 | |
|
|
766 | sub aio_load($$;$) { |
|
|
767 | my ($path, undef, $cb) = @_; |
|
|
768 | my $data = \$_[1]; |
|
|
769 | |
|
|
770 | my $pri = aioreq_pri; |
|
|
771 | my $grp = aio_group $cb; |
|
|
772 | |
|
|
773 | aioreq_pri $pri; |
|
|
774 | add $grp aio_open $path, O_RDONLY, 0, sub { |
|
|
775 | my $fh = shift |
|
|
776 | or return $grp->result (-1); |
|
|
777 | |
|
|
778 | aioreq_pri $pri; |
|
|
779 | add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { |
|
|
780 | $grp->result ($_[0]); |
|
|
781 | }; |
|
|
782 | }; |
|
|
783 | |
|
|
784 | $grp |
|
|
785 | } |
|
|
786 | |
|
|
787 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
788 | |
|
|
789 | Try to copy the I<file> (directories not supported as either source or |
|
|
790 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
791 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
|
|
792 | |
|
|
793 | This is a composite request that creates the destination file with |
|
|
794 | mode 0200 and copies the contents of the source file into it using |
|
|
795 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
|
|
796 | uid/gid, in that order. |
|
|
797 | |
|
|
798 | If an error occurs, the partial destination file will be unlinked, if |
|
|
799 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
800 | errors are being ignored. |
|
|
801 | |
|
|
802 | =cut |
|
|
803 | |
|
|
804 | sub aio_copy($$;$) { |
|
|
805 | my ($src, $dst, $cb) = @_; |
|
|
806 | |
|
|
807 | my $pri = aioreq_pri; |
|
|
808 | my $grp = aio_group $cb; |
|
|
809 | |
|
|
810 | aioreq_pri $pri; |
|
|
811 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
812 | if (my $src_fh = $_[0]) { |
|
|
813 | my @stat = stat $src_fh; # hmm, might block over nfs? |
|
|
814 | |
|
|
815 | aioreq_pri $pri; |
|
|
816 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
817 | if (my $dst_fh = $_[0]) { |
|
|
818 | aioreq_pri $pri; |
|
|
819 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
820 | if ($_[0] == $stat[7]) { |
|
|
821 | $grp->result (0); |
|
|
822 | close $src_fh; |
|
|
823 | |
|
|
824 | my $ch = sub { |
|
|
825 | aioreq_pri $pri; |
|
|
826 | add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub { |
|
|
827 | aioreq_pri $pri; |
|
|
828 | add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub { |
|
|
829 | aioreq_pri $pri; |
|
|
830 | add $grp aio_close $dst_fh; |
|
|
831 | } |
|
|
832 | }; |
|
|
833 | }; |
|
|
834 | |
|
|
835 | aioreq_pri $pri; |
|
|
836 | add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub { |
|
|
837 | if ($_[0] < 0 && $! == ENOSYS) { |
|
|
838 | aioreq_pri $pri; |
|
|
839 | add $grp aio_utime $dst, $stat[8], $stat[9], $ch; |
|
|
840 | } else { |
|
|
841 | $ch->(); |
|
|
842 | } |
|
|
843 | }; |
|
|
844 | } else { |
|
|
845 | $grp->result (-1); |
|
|
846 | close $src_fh; |
|
|
847 | close $dst_fh; |
|
|
848 | |
|
|
849 | aioreq $pri; |
|
|
850 | add $grp aio_unlink $dst; |
|
|
851 | } |
|
|
852 | }; |
|
|
853 | } else { |
|
|
854 | $grp->result (-1); |
|
|
855 | } |
|
|
856 | }, |
|
|
857 | |
|
|
858 | } else { |
|
|
859 | $grp->result (-1); |
|
|
860 | } |
|
|
861 | }; |
|
|
862 | |
|
|
863 | $grp |
|
|
864 | } |
|
|
865 | |
|
|
866 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
867 | |
|
|
868 | Try to move the I<file> (directories not supported as either source or |
|
|
869 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
870 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
|
|
871 | |
|
|
872 | This is a composite request that tries to rename(2) the file first; if |
|
|
873 | rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
874 | that is successful, unlinks the C<$srcpath>. |
|
|
875 | |
|
|
876 | =cut |
|
|
877 | |
|
|
878 | sub aio_move($$;$) { |
|
|
879 | my ($src, $dst, $cb) = @_; |
|
|
880 | |
|
|
881 | my $pri = aioreq_pri; |
|
|
882 | my $grp = aio_group $cb; |
|
|
883 | |
|
|
884 | aioreq_pri $pri; |
|
|
885 | add $grp aio_rename $src, $dst, sub { |
|
|
886 | if ($_[0] && $! == EXDEV) { |
|
|
887 | aioreq_pri $pri; |
|
|
888 | add $grp aio_copy $src, $dst, sub { |
|
|
889 | $grp->result ($_[0]); |
|
|
890 | |
|
|
891 | unless ($_[0]) { |
|
|
892 | aioreq_pri $pri; |
|
|
893 | add $grp aio_unlink $src; |
|
|
894 | } |
|
|
895 | }; |
|
|
896 | } else { |
|
|
897 | $grp->result ($_[0]); |
|
|
898 | } |
|
|
899 | }; |
|
|
900 | |
|
|
901 | $grp |
|
|
902 | } |
|
|
903 | |
|
|
904 | =item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
|
|
905 | |
|
|
906 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
|
|
907 | efficiently separate the entries of directory C<$path> into two sets of |
|
|
908 | names, directories you can recurse into (directories), and ones you cannot |
|
|
909 | recurse into (everything else, including symlinks to directories). |
|
|
910 | |
|
|
911 | C<aio_scandir> is a composite request that creates of many sub requests_ |
|
|
912 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
|
|
913 | this function generates. If it is C<< <= 0 >>, then a suitable default |
|
|
914 | will be chosen (currently 4). |
|
|
915 | |
|
|
916 | On error, the callback is called without arguments, otherwise it receives |
|
|
917 | two array-refs with path-relative entry names. |
|
|
918 | |
|
|
919 | Example: |
|
|
920 | |
|
|
921 | aio_scandir $dir, 0, sub { |
|
|
922 | my ($dirs, $nondirs) = @_; |
|
|
923 | print "real directories: @$dirs\n"; |
|
|
924 | print "everything else: @$nondirs\n"; |
|
|
925 | }; |
|
|
926 | |
|
|
927 | Implementation notes. |
|
|
928 | |
|
|
929 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
|
|
930 | |
|
|
931 | If readdir returns file type information, then this is used directly to |
|
|
932 | find directories. |
|
|
933 | |
|
|
934 | Otherwise, after reading the directory, the modification time, size etc. |
|
|
935 | of the directory before and after the readdir is checked, and if they |
|
|
936 | match (and isn't the current time), the link count will be used to decide |
|
|
937 | how many entries are directories (if >= 2). Otherwise, no knowledge of the |
|
|
938 | number of subdirectories will be assumed. |
|
|
939 | |
|
|
940 | Then entries will be sorted into likely directories a non-initial dot |
|
|
941 | currently) and likely non-directories (see C<aio_readdirx>). Then every |
|
|
942 | entry plus an appended C</.> will be C<stat>'ed, likely directories first, |
|
|
943 | in order of their inode numbers. If that succeeds, it assumes that the |
|
|
944 | entry is a directory or a symlink to directory (which will be checked |
|
|
945 | separately). This is often faster than stat'ing the entry itself because |
|
|
946 | filesystems might detect the type of the entry without reading the inode |
|
|
947 | data (e.g. ext2fs filetype feature), even on systems that cannot return |
|
|
948 | the filetype information on readdir. |
|
|
949 | |
|
|
950 | If the known number of directories (link count - 2) has been reached, the |
|
|
951 | rest of the entries is assumed to be non-directories. |
|
|
952 | |
|
|
953 | This only works with certainty on POSIX (= UNIX) filesystems, which |
|
|
954 | fortunately are the vast majority of filesystems around. |
|
|
955 | |
|
|
956 | It will also likely work on non-POSIX filesystems with reduced efficiency |
|
|
957 | as those tend to return 0 or 1 as link counts, which disables the |
|
|
958 | directory counting heuristic. |
|
|
959 | |
|
|
960 | =cut |
|
|
961 | |
|
|
962 | sub aio_scandir($$;$) { |
|
|
963 | my ($path, $maxreq, $cb) = @_; |
|
|
964 | |
|
|
965 | my $pri = aioreq_pri; |
|
|
966 | |
|
|
967 | my $grp = aio_group $cb; |
|
|
968 | |
|
|
969 | $maxreq = 4 if $maxreq <= 0; |
|
|
970 | |
|
|
971 | # stat once |
|
|
972 | aioreq_pri $pri; |
|
|
973 | add $grp aio_stat $path, sub { |
|
|
974 | return $grp->result () if $_[0]; |
|
|
975 | my $now = time; |
|
|
976 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
977 | |
|
|
978 | # read the directory entries |
|
|
979 | aioreq_pri $pri; |
|
|
980 | add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { |
|
|
981 | my $entries = shift |
|
|
982 | or return $grp->result (); |
|
|
983 | |
|
|
984 | # stat the dir another time |
|
|
985 | aioreq_pri $pri; |
|
|
986 | add $grp aio_stat $path, sub { |
|
|
987 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
|
|
988 | |
|
|
989 | my $ndirs; |
|
|
990 | |
|
|
991 | # take the slow route if anything looks fishy |
|
|
992 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
|
|
993 | $ndirs = -1; |
|
|
994 | } else { |
|
|
995 | # if nlink == 2, we are finished |
|
|
996 | # for non-posix-fs's, we rely on nlink < 2 |
|
|
997 | $ndirs = (stat _)[3] - 2 |
|
|
998 | or return $grp->result ([], $entries); |
|
|
999 | } |
|
|
1000 | |
|
|
1001 | my (@dirs, @nondirs); |
|
|
1002 | |
|
|
1003 | my $statgrp = add $grp aio_group sub { |
|
|
1004 | $grp->result (\@dirs, \@nondirs); |
|
|
1005 | }; |
|
|
1006 | |
|
|
1007 | limit $statgrp $maxreq; |
|
|
1008 | feed $statgrp sub { |
|
|
1009 | return unless @$entries; |
|
|
1010 | my $entry = shift @$entries; |
|
|
1011 | |
|
|
1012 | aioreq_pri $pri; |
|
|
1013 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
1014 | if ($_[0] < 0) { |
|
|
1015 | push @nondirs, $entry; |
|
|
1016 | } else { |
|
|
1017 | # need to check for real directory |
|
|
1018 | aioreq_pri $pri; |
|
|
1019 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
1020 | if (-d _) { |
|
|
1021 | push @dirs, $entry; |
|
|
1022 | |
|
|
1023 | unless (--$ndirs) { |
|
|
1024 | push @nondirs, @$entries; |
|
|
1025 | feed $statgrp; |
|
|
1026 | } |
|
|
1027 | } else { |
|
|
1028 | push @nondirs, $entry; |
|
|
1029 | } |
|
|
1030 | } |
|
|
1031 | } |
|
|
1032 | }; |
|
|
1033 | }; |
|
|
1034 | }; |
|
|
1035 | }; |
|
|
1036 | }; |
|
|
1037 | |
|
|
1038 | $grp |
|
|
1039 | } |
|
|
1040 | |
|
|
1041 | =item aio_rmtree $pathname, $callback->($status) |
|
|
1042 | |
|
|
1043 | Delete a directory tree starting (and including) C<$path>, return the |
|
|
1044 | status of the final C<rmdir> only. This is a composite request that |
|
|
1045 | uses C<aio_scandir> to recurse into and rmdir directories, and unlink |
|
|
1046 | everything else. |
|
|
1047 | |
|
|
1048 | =cut |
|
|
1049 | |
|
|
1050 | sub aio_rmtree; |
|
|
1051 | sub aio_rmtree($;$) { |
|
|
1052 | my ($path, $cb) = @_; |
|
|
1053 | |
|
|
1054 | my $pri = aioreq_pri; |
|
|
1055 | my $grp = aio_group $cb; |
|
|
1056 | |
|
|
1057 | aioreq_pri $pri; |
|
|
1058 | add $grp aio_scandir $path, 0, sub { |
|
|
1059 | my ($dirs, $nondirs) = @_; |
|
|
1060 | |
|
|
1061 | my $dirgrp = aio_group sub { |
|
|
1062 | add $grp aio_rmdir $path, sub { |
|
|
1063 | $grp->result ($_[0]); |
|
|
1064 | }; |
|
|
1065 | }; |
|
|
1066 | |
|
|
1067 | (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs; |
|
|
1068 | (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs; |
|
|
1069 | |
|
|
1070 | add $grp $dirgrp; |
|
|
1071 | }; |
|
|
1072 | |
|
|
1073 | $grp |
|
|
1074 | } |
|
|
1075 | |
|
|
1076 | =item aio_sync $callback->($status) |
|
|
1077 | |
|
|
1078 | Asynchronously call sync and call the callback when finished. |
|
|
1079 | |
184 | =item aio_fsync $fh, $callback |
1080 | =item aio_fsync $fh, $callback->($status) |
185 | |
1081 | |
186 | Asynchronously call fsync on the given filehandle and call the callback |
1082 | Asynchronously call fsync on the given filehandle and call the callback |
187 | with the fsync result code. |
1083 | with the fsync result code. |
188 | |
1084 | |
189 | =item aio_fdatasync $fh, $callback |
1085 | =item aio_fdatasync $fh, $callback->($status) |
190 | |
1086 | |
191 | Asynchronously call fdatasync on the given filehandle and call the |
1087 | Asynchronously call fdatasync on the given filehandle and call the |
192 | callback with the fdatasync result code. |
1088 | callback with the fdatasync result code. |
193 | |
1089 | |
|
|
1090 | If this call isn't available because your OS lacks it or it couldn't be |
|
|
1091 | detected, it will be emulated by calling C<fsync> instead. |
|
|
1092 | |
|
|
1093 | =item aio_syncfs $fh, $callback->($status) |
|
|
1094 | |
|
|
1095 | Asynchronously call the syncfs syscall to sync the filesystem associated |
|
|
1096 | to the given filehandle and call the callback with the syncfs result |
|
|
1097 | code. If syncfs is not available, calls sync(), but returns C<-1> and sets |
|
|
1098 | errno to C<ENOSYS> nevertheless. |
|
|
1099 | |
|
|
1100 | =item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
1101 | |
|
|
1102 | Sync the data portion of the file specified by C<$offset> and C<$length> |
|
|
1103 | to disk (but NOT the metadata), by calling the Linux-specific |
|
|
1104 | sync_file_range call. If sync_file_range is not available or it returns |
|
|
1105 | ENOSYS, then fdatasync or fsync is being substituted. |
|
|
1106 | |
|
|
1107 | C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, |
|
|
1108 | C<IO::AIO::SYNC_FILE_RANGE_WRITE> and |
|
|
1109 | C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range |
|
|
1110 | manpage for details. |
|
|
1111 | |
|
|
1112 | =item aio_pathsync $pathname, $callback->($status) |
|
|
1113 | |
|
|
1114 | This request tries to open, fsync and close the given path. This is a |
|
|
1115 | composite request intended to sync directories after directory operations |
|
|
1116 | (E.g. rename). This might not work on all operating systems or have any |
|
|
1117 | specific effect, but usually it makes sure that directory changes get |
|
|
1118 | written to disc. It works for anything that can be opened for read-only, |
|
|
1119 | not just directories. |
|
|
1120 | |
|
|
1121 | Future versions of this function might fall back to other methods when |
|
|
1122 | C<fsync> on the directory fails (such as calling C<sync>). |
|
|
1123 | |
|
|
1124 | Passes C<0> when everything went ok, and C<-1> on error. |
|
|
1125 | |
|
|
1126 | =cut |
|
|
1127 | |
|
|
1128 | sub aio_pathsync($;$) { |
|
|
1129 | my ($path, $cb) = @_; |
|
|
1130 | |
|
|
1131 | my $pri = aioreq_pri; |
|
|
1132 | my $grp = aio_group $cb; |
|
|
1133 | |
|
|
1134 | aioreq_pri $pri; |
|
|
1135 | add $grp aio_open $path, O_RDONLY, 0, sub { |
|
|
1136 | my ($fh) = @_; |
|
|
1137 | if ($fh) { |
|
|
1138 | aioreq_pri $pri; |
|
|
1139 | add $grp aio_fsync $fh, sub { |
|
|
1140 | $grp->result ($_[0]); |
|
|
1141 | |
|
|
1142 | aioreq_pri $pri; |
|
|
1143 | add $grp aio_close $fh; |
|
|
1144 | }; |
|
|
1145 | } else { |
|
|
1146 | $grp->result (-1); |
|
|
1147 | } |
|
|
1148 | }; |
|
|
1149 | |
|
|
1150 | $grp |
|
|
1151 | } |
|
|
1152 | |
|
|
1153 | =item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1154 | |
|
|
1155 | This is a rather advanced IO::AIO call, which only works on mmap(2)ed |
|
|
1156 | scalars (see the C<IO::AIO::mmap> function, although it also works on data |
|
|
1157 | scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the |
|
|
1158 | scalar must only be modified in-place while an aio operation is pending on |
|
|
1159 | it). |
|
|
1160 | |
|
|
1161 | It calls the C<msync> function of your OS, if available, with the memory |
|
|
1162 | area starting at C<$offset> in the string and ending C<$length> bytes |
|
|
1163 | later. If C<$length> is negative, counts from the end, and if C<$length> |
|
|
1164 | is C<undef>, then it goes till the end of the string. The flags can be |
|
|
1165 | a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and |
|
|
1166 | C<IO::AIO::MS_SYNC>. |
|
|
1167 | |
|
|
1168 | =item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1169 | |
|
|
1170 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1171 | scalars. |
|
|
1172 | |
|
|
1173 | It touches (reads or writes) all memory pages in the specified |
|
|
1174 | range inside the scalar. All caveats and parameters are the same |
|
|
1175 | as for C<aio_msync>, above, except for flags, which must be either |
|
|
1176 | C<0> (which reads all pages and ensures they are instantiated) or |
|
|
1177 | C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and |
|
|
1178 | writing an octet from it, which dirties the page). |
|
|
1179 | |
|
|
1180 | =item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
1181 | |
|
|
1182 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1183 | scalars. |
|
|
1184 | |
|
|
1185 | It reads in all the pages of the underlying storage into memory (if any) |
|
|
1186 | and locks them, so they are not getting swapped/paged out or removed. |
|
|
1187 | |
|
|
1188 | If C<$length> is undefined, then the scalar will be locked till the end. |
|
|
1189 | |
|
|
1190 | On systems that do not implement C<mlock>, this function returns C<-1> |
|
|
1191 | and sets errno to C<ENOSYS>. |
|
|
1192 | |
|
|
1193 | Note that the corresponding C<munlock> is synchronous and is |
|
|
1194 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1195 | |
|
|
1196 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
1197 | C<$data> gets destroyed. |
|
|
1198 | |
|
|
1199 | open my $fh, "<", $path or die "$path: $!"; |
|
|
1200 | my $data; |
|
|
1201 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
1202 | aio_mlock $data; # mlock in background |
|
|
1203 | |
|
|
1204 | =item aio_mlockall $flags, $callback->($status) |
|
|
1205 | |
|
|
1206 | Calls the C<mlockall> function with the given C<$flags> (a combination of |
|
|
1207 | C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). |
|
|
1208 | |
|
|
1209 | On systems that do not implement C<mlockall>, this function returns C<-1> |
|
|
1210 | and sets errno to C<ENOSYS>. |
|
|
1211 | |
|
|
1212 | Note that the corresponding C<munlockall> is synchronous and is |
|
|
1213 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1214 | |
|
|
1215 | Example: asynchronously lock all current and future pages into memory. |
|
|
1216 | |
|
|
1217 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
1218 | |
|
|
1219 | =item aio_group $callback->(...) |
|
|
1220 | |
|
|
1221 | This is a very special aio request: Instead of doing something, it is a |
|
|
1222 | container for other aio requests, which is useful if you want to bundle |
|
|
1223 | many requests into a single, composite, request with a definite callback |
|
|
1224 | and the ability to cancel the whole request with its subrequests. |
|
|
1225 | |
|
|
1226 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
1227 | for more info. |
|
|
1228 | |
|
|
1229 | Example: |
|
|
1230 | |
|
|
1231 | my $grp = aio_group sub { |
|
|
1232 | print "all stats done\n"; |
|
|
1233 | }; |
|
|
1234 | |
|
|
1235 | add $grp |
|
|
1236 | (aio_stat ...), |
|
|
1237 | (aio_stat ...), |
|
|
1238 | ...; |
|
|
1239 | |
|
|
1240 | =item aio_nop $callback->() |
|
|
1241 | |
|
|
1242 | This is a special request - it does nothing in itself and is only used for |
|
|
1243 | side effects, such as when you want to add a dummy request to a group so |
|
|
1244 | that finishing the requests in the group depends on executing the given |
|
|
1245 | code. |
|
|
1246 | |
|
|
1247 | While this request does nothing, it still goes through the execution |
|
|
1248 | phase and still requires a worker thread. Thus, the callback will not |
|
|
1249 | be executed immediately but only after other requests in the queue have |
|
|
1250 | entered their execution phase. This can be used to measure request |
|
|
1251 | latency. |
|
|
1252 | |
|
|
1253 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
|
|
1254 | |
|
|
1255 | Mainly used for debugging and benchmarking, this aio request puts one of |
|
|
1256 | the request workers to sleep for the given time. |
|
|
1257 | |
|
|
1258 | While it is theoretically handy to have simple I/O scheduling requests |
|
|
1259 | like sleep and file handle readable/writable, the overhead this creates is |
|
|
1260 | immense (it blocks a thread for a long time) so do not use this function |
|
|
1261 | except to put your application under artificial I/O pressure. |
|
|
1262 | |
194 | =back |
1263 | =back |
195 | |
1264 | |
|
|
1265 | |
|
|
1266 | =head2 IO::AIO::WD - multiple working directories |
|
|
1267 | |
|
|
1268 | Your process only has one current working directory, which is used by all |
|
|
1269 | threads. This makes it hard to use relative paths (some other component |
|
|
1270 | could call C<chdir> at any time, and it is hard to control when the path |
|
|
1271 | will be used by IO::AIO). |
|
|
1272 | |
|
|
1273 | One solution for this is to always use absolute paths. This usually works, |
|
|
1274 | but can be quite slow (the kernel has to walk the whole path on every |
|
|
1275 | access), and can also be a hassle to implement. |
|
|
1276 | |
|
|
1277 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
1278 | futimensat and so on) that make it possible to specify working directories |
|
|
1279 | per operation. |
|
|
1280 | |
|
|
1281 | For portability, and because the clowns who "designed", or shall I write, |
|
|
1282 | perpetrated this new interface were obviously half-drunk, this abstraction |
|
|
1283 | cannot be perfect, though. |
|
|
1284 | |
|
|
1285 | IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD |
|
|
1286 | object. This object stores the canonicalised, absolute version of the |
|
|
1287 | path, and on systems that allow it, also a directory file descriptor. |
|
|
1288 | |
|
|
1289 | Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> |
|
|
1290 | or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD |
|
|
1291 | object and a pathname instead. If the pathname is absolute, the |
|
|
1292 | IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative |
|
|
1293 | to that IO::AIO::WD object. |
|
|
1294 | |
|
|
1295 | For example, to get a wd object for F</etc> and then stat F<passwd> |
|
|
1296 | inside, you would write: |
|
|
1297 | |
|
|
1298 | aio_wd "/etc", sub { |
|
|
1299 | my $etcdir = shift; |
|
|
1300 | |
|
|
1301 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1302 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1303 | # when $etcdir is undef. |
|
|
1304 | |
|
|
1305 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1306 | # yay |
|
|
1307 | }; |
|
|
1308 | }; |
|
|
1309 | |
|
|
1310 | This shows that creating an IO::AIO::WD object is itself a potentially |
|
|
1311 | blocking operation, which is why it is done asynchronously. |
|
|
1312 | |
|
|
1313 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1314 | object and the pathname string, so you could write the following without |
|
|
1315 | causing any issues due to C<$path> getting reused: |
|
|
1316 | |
|
|
1317 | my $path = [$wd, undef]; |
|
|
1318 | |
|
|
1319 | for my $name (qw(abc def ghi)) { |
|
|
1320 | $path->[1] = $name; |
|
|
1321 | aio_stat $path, sub { |
|
|
1322 | # ... |
|
|
1323 | }; |
|
|
1324 | } |
|
|
1325 | |
|
|
1326 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1327 | pathname string doesn't change, so will point to the new directory (or |
|
|
1328 | nowhere at all), while the directory fd, if available on the system, |
|
|
1329 | will still point to the original directory. Most functions accepting a |
|
|
1330 | pathname will use the directory fd on newer systems, and the string on |
|
|
1331 | older systems. Some functions (such as realpath) will always rely on the |
|
|
1332 | string form of the pathname. |
|
|
1333 | |
|
|
1334 | So this fucntionality is mainly useful to get some protection against |
|
|
1335 | C<chdir>, to easily get an absolute path out of a relative path for future |
|
|
1336 | reference, and to speed up doing many operations in the same directory |
|
|
1337 | (e.g. when stat'ing all files in a directory). |
|
|
1338 | |
|
|
1339 | The following functions implement this working directory abstraction: |
|
|
1340 | |
|
|
1341 | =over 4 |
|
|
1342 | |
|
|
1343 | =item aio_wd $pathname, $callback->($wd) |
|
|
1344 | |
|
|
1345 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1346 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1347 | system, also open a directory fd to speed up pathname resolution relative |
|
|
1348 | to this working directory. |
|
|
1349 | |
|
|
1350 | If something goes wrong, then C<undef> is passwd to the callback instead |
|
|
1351 | of a working directory object and C<$!> is set appropriately. Since |
|
|
1352 | passing C<undef> as working directory component of a pathname fails the |
|
|
1353 | request with C<ENOENT>, there is often no need for error checking in the |
|
|
1354 | C<aio_wd> callback, as future requests using the value will fail in the |
|
|
1355 | expected way. |
|
|
1356 | |
|
|
1357 | If this call isn't available because your OS lacks it or it couldn't be |
|
|
1358 | detected, it will be emulated by calling C<fsync> instead. |
|
|
1359 | |
|
|
1360 | =item IO::AIO::CWD |
|
|
1361 | |
|
|
1362 | This is a compiletime constant (object) that represents the process |
|
|
1363 | current working directory. |
|
|
1364 | |
|
|
1365 | Specifying this object as working directory object for a pathname is as |
|
|
1366 | if the pathname would be specified directly, without a directory object, |
|
|
1367 | e.g., these calls are functionally identical: |
|
|
1368 | |
|
|
1369 | aio_stat "somefile", sub { ... }; |
|
|
1370 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1371 | |
|
|
1372 | =back |
|
|
1373 | |
|
|
1374 | |
|
|
1375 | =head2 IO::AIO::REQ CLASS |
|
|
1376 | |
|
|
1377 | All non-aggregate C<aio_*> functions return an object of this class when |
|
|
1378 | called in non-void context. |
|
|
1379 | |
|
|
1380 | =over 4 |
|
|
1381 | |
|
|
1382 | =item cancel $req |
|
|
1383 | |
|
|
1384 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
1385 | when entering the B<execute> state and skipping calling the callback when |
|
|
1386 | entering the the B<result> state, but will leave the request otherwise |
|
|
1387 | untouched (with the exception of readdir). That means that requests that |
|
|
1388 | currently execute will not be stopped and resources held by the request |
|
|
1389 | will not be freed prematurely. |
|
|
1390 | |
|
|
1391 | =item cb $req $callback->(...) |
|
|
1392 | |
|
|
1393 | Replace (or simply set) the callback registered to the request. |
|
|
1394 | |
|
|
1395 | =back |
|
|
1396 | |
|
|
1397 | =head2 IO::AIO::GRP CLASS |
|
|
1398 | |
|
|
1399 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
1400 | objects of this class, too. |
|
|
1401 | |
|
|
1402 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
1403 | aio requests. |
|
|
1404 | |
|
|
1405 | You create one by calling the C<aio_group> constructing function with a |
|
|
1406 | callback that will be called when all contained requests have entered the |
|
|
1407 | C<done> state: |
|
|
1408 | |
|
|
1409 | my $grp = aio_group sub { |
|
|
1410 | print "all requests are done\n"; |
|
|
1411 | }; |
|
|
1412 | |
|
|
1413 | You add requests by calling the C<add> method with one or more |
|
|
1414 | C<IO::AIO::REQ> objects: |
|
|
1415 | |
|
|
1416 | $grp->add (aio_unlink "..."); |
|
|
1417 | |
|
|
1418 | add $grp aio_stat "...", sub { |
|
|
1419 | $_[0] or return $grp->result ("error"); |
|
|
1420 | |
|
|
1421 | # add another request dynamically, if first succeeded |
|
|
1422 | add $grp aio_open "...", sub { |
|
|
1423 | $grp->result ("ok"); |
|
|
1424 | }; |
|
|
1425 | }; |
|
|
1426 | |
|
|
1427 | This makes it very easy to create composite requests (see the source of |
|
|
1428 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
1429 | |
|
|
1430 | =over 4 |
|
|
1431 | |
|
|
1432 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
1433 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
1434 | |
|
|
1435 | =item * They can be canceled like any other request. Canceling will cancel not |
|
|
1436 | only the request itself, but also all requests it contains. |
|
|
1437 | |
|
|
1438 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
1439 | |
|
|
1440 | =item * You must not add requests to a group from within the group callback (or |
|
|
1441 | any later time). |
|
|
1442 | |
|
|
1443 | =back |
|
|
1444 | |
|
|
1445 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
1446 | will finish very quickly. If they contain only requests that are in the |
|
|
1447 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
1448 | exist. |
|
|
1449 | |
|
|
1450 | That means after creating a group you have some time to add requests |
|
|
1451 | (precisely before the callback has been invoked, which is only done within |
|
|
1452 | the C<poll_cb>). And in the callbacks of those requests, you can add |
|
|
1453 | further requests to the group. And only when all those requests have |
|
|
1454 | finished will the the group itself finish. |
|
|
1455 | |
|
|
1456 | =over 4 |
|
|
1457 | |
|
|
1458 | =item add $grp ... |
|
|
1459 | |
|
|
1460 | =item $grp->add (...) |
|
|
1461 | |
|
|
1462 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
|
|
1463 | be added, including other groups, as long as you do not create circular |
|
|
1464 | dependencies. |
|
|
1465 | |
|
|
1466 | Returns all its arguments. |
|
|
1467 | |
|
|
1468 | =item $grp->cancel_subs |
|
|
1469 | |
|
|
1470 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
1471 | itself. Useful when you queued a lot of events but got a result early. |
|
|
1472 | |
|
|
1473 | The group request will finish normally (you cannot add requests to the |
|
|
1474 | group). |
|
|
1475 | |
|
|
1476 | =item $grp->result (...) |
|
|
1477 | |
|
|
1478 | Set the result value(s) that will be passed to the group callback when all |
|
|
1479 | subrequests have finished and set the groups errno to the current value |
|
|
1480 | of errno (just like calling C<errno> without an error number). By default, |
|
|
1481 | no argument will be passed and errno is zero. |
|
|
1482 | |
|
|
1483 | =item $grp->errno ([$errno]) |
|
|
1484 | |
|
|
1485 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
1486 | when the argument is missing. |
|
|
1487 | |
|
|
1488 | Every aio request has an associated errno value that is restored when |
|
|
1489 | the callback is invoked. This method lets you change this value from its |
|
|
1490 | default (0). |
|
|
1491 | |
|
|
1492 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
1493 | before the call to C<result>, or call c<errno> after it. |
|
|
1494 | |
|
|
1495 | =item feed $grp $callback->($grp) |
|
|
1496 | |
|
|
1497 | Sets a feeder/generator on this group: every group can have an attached |
|
|
1498 | generator that generates requests if idle. The idea behind this is that, |
|
|
1499 | although you could just queue as many requests as you want in a group, |
|
|
1500 | this might starve other requests for a potentially long time. For example, |
|
|
1501 | C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, |
|
|
1502 | delaying any later requests for a long time. |
|
|
1503 | |
|
|
1504 | To avoid this, and allow incremental generation of requests, you can |
|
|
1505 | instead a group and set a feeder on it that generates those requests. The |
|
|
1506 | feed callback will be called whenever there are few enough (see C<limit>, |
|
|
1507 | below) requests active in the group itself and is expected to queue more |
|
|
1508 | requests. |
|
|
1509 | |
|
|
1510 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
|
|
1511 | not impose any limits). |
|
|
1512 | |
|
|
1513 | If the feed does not queue more requests when called, it will be |
|
|
1514 | automatically removed from the group. |
|
|
1515 | |
|
|
1516 | If the feed limit is C<0> when this method is called, it will be set to |
|
|
1517 | C<2> automatically. |
|
|
1518 | |
|
|
1519 | Example: |
|
|
1520 | |
|
|
1521 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
1522 | |
|
|
1523 | my $grp = aio_group sub { print "finished\n" }; |
|
|
1524 | limit $grp 4; |
|
|
1525 | feed $grp sub { |
|
|
1526 | my $file = pop @files |
|
|
1527 | or return; |
|
|
1528 | |
|
|
1529 | add $grp aio_stat $file, sub { ... }; |
|
|
1530 | }; |
|
|
1531 | |
|
|
1532 | =item limit $grp $num |
|
|
1533 | |
|
|
1534 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
1535 | the group contains less than this many requests. |
|
|
1536 | |
|
|
1537 | Setting the limit to C<0> will pause the feeding process. |
|
|
1538 | |
|
|
1539 | The default value for the limit is C<0>, but note that setting a feeder |
|
|
1540 | automatically bumps it up to C<2>. |
|
|
1541 | |
|
|
1542 | =back |
|
|
1543 | |
196 | =head2 SUPPORT FUNCTIONS |
1544 | =head2 SUPPORT FUNCTIONS |
197 | |
1545 | |
|
|
1546 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
1547 | |
198 | =over 4 |
1548 | =over 4 |
199 | |
1549 | |
200 | =item $fileno = IO::AIO::poll_fileno |
1550 | =item $fileno = IO::AIO::poll_fileno |
201 | |
1551 | |
202 | Return the I<request result pipe filehandle>. This filehandle must be |
1552 | Return the I<request result pipe file descriptor>. This filehandle must be |
203 | polled for reading by some mechanism outside this module (e.g. Event |
1553 | polled for reading by some mechanism outside this module (e.g. EV, Glib, |
204 | or select, see below). If the pipe becomes readable you have to call |
1554 | select and so on, see below or the SYNOPSIS). If the pipe becomes readable |
205 | C<poll_cb> to check the results. |
1555 | you have to call C<poll_cb> to check the results. |
206 | |
1556 | |
207 | See C<poll_cb> for an example. |
1557 | See C<poll_cb> for an example. |
208 | |
1558 | |
209 | =item IO::AIO::poll_cb |
1559 | =item IO::AIO::poll_cb |
210 | |
1560 | |
211 | Process all outstanding events on the result pipe. You have to call this |
1561 | Process some outstanding events on the result pipe. You have to call |
212 | regularly. Returns the number of events processed. Returns immediately |
1562 | this regularly. Returns C<0> if all events could be processed (or there |
213 | when no events are outstanding. |
1563 | were no events to process), or C<-1> if it returned earlier for whatever |
|
|
1564 | reason. Returns immediately when no events are outstanding. The amount of |
|
|
1565 | events processed depends on the settings of C<IO::AIO::max_poll_req> and |
|
|
1566 | C<IO::AIO::max_poll_time>. |
214 | |
1567 | |
215 | You can use Event to multiplex, e.g.: |
1568 | If not all requests were processed for whatever reason, the filehandle |
|
|
1569 | will still be ready when C<poll_cb> returns, so normally you don't have to |
|
|
1570 | do anything special to have it called later. |
|
|
1571 | |
|
|
1572 | Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes |
|
|
1573 | ready, it can be beneficial to call this function from loops which submit |
|
|
1574 | a lot of requests, to make sure the results get processed when they become |
|
|
1575 | available and not just when the loop is finished and the event loop takes |
|
|
1576 | over again. This function returns very fast when there are no outstanding |
|
|
1577 | requests. |
|
|
1578 | |
|
|
1579 | Example: Install an Event watcher that automatically calls |
|
|
1580 | IO::AIO::poll_cb with high priority (more examples can be found in the |
|
|
1581 | SYNOPSIS section, at the top of this document): |
216 | |
1582 | |
217 | Event->io (fd => IO::AIO::poll_fileno, |
1583 | Event->io (fd => IO::AIO::poll_fileno, |
218 | poll => 'r', async => 1, |
1584 | poll => 'r', async => 1, |
219 | cb => \&IO::AIO::poll_cb); |
1585 | cb => \&IO::AIO::poll_cb); |
220 | |
1586 | |
221 | =item IO::AIO::poll_wait |
1587 | =item IO::AIO::poll_wait |
222 | |
1588 | |
|
|
1589 | If there are any outstanding requests and none of them in the result |
223 | Wait till the result filehandle becomes ready for reading (simply does a |
1590 | phase, wait till the result filehandle becomes ready for reading (simply |
224 | select on the filehandle. This is useful if you want to synchronously wait |
1591 | does a C<select> on the filehandle. This is useful if you want to |
225 | for some requests to finish). |
1592 | synchronously wait for some requests to finish). |
226 | |
1593 | |
227 | See C<nreqs> for an example. |
1594 | See C<nreqs> for an example. |
228 | |
1595 | |
|
|
1596 | =item IO::AIO::poll |
|
|
1597 | |
|
|
1598 | Waits until some requests have been handled. |
|
|
1599 | |
|
|
1600 | Returns the number of requests processed, but is otherwise strictly |
|
|
1601 | equivalent to: |
|
|
1602 | |
|
|
1603 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1604 | |
229 | =item IO::AIO::nreqs |
1605 | =item IO::AIO::flush |
230 | |
1606 | |
231 | Returns the number of requests currently outstanding. |
1607 | Wait till all outstanding AIO requests have been handled. |
232 | |
1608 | |
233 | Example: wait till there are no outstanding requests anymore: |
1609 | Strictly equivalent to: |
234 | |
1610 | |
235 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1611 | IO::AIO::poll_wait, IO::AIO::poll_cb |
236 | while IO::AIO::nreqs; |
1612 | while IO::AIO::nreqs; |
237 | |
1613 | |
|
|
1614 | =item IO::AIO::max_poll_reqs $nreqs |
|
|
1615 | |
|
|
1616 | =item IO::AIO::max_poll_time $seconds |
|
|
1617 | |
|
|
1618 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
1619 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
1620 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
1621 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
1622 | of time C<poll_cb> is allowed to use). |
|
|
1623 | |
|
|
1624 | Setting C<max_poll_time> to a non-zero value creates an overhead of one |
|
|
1625 | syscall per request processed, which is not normally a problem unless your |
|
|
1626 | callbacks are really really fast or your OS is really really slow (I am |
|
|
1627 | not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead. |
|
|
1628 | |
|
|
1629 | Setting these is useful if you want to ensure some level of |
|
|
1630 | interactiveness when perl is not fast enough to process all requests in |
|
|
1631 | time. |
|
|
1632 | |
|
|
1633 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
|
|
1634 | |
|
|
1635 | Example: Install an Event watcher that automatically calls |
|
|
1636 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
|
|
1637 | program get the CPU sometimes even under high AIO load. |
|
|
1638 | |
|
|
1639 | # try not to spend much more than 0.1s in poll_cb |
|
|
1640 | IO::AIO::max_poll_time 0.1; |
|
|
1641 | |
|
|
1642 | # use a low priority so other tasks have priority |
|
|
1643 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1644 | poll => 'r', nice => 1, |
|
|
1645 | cb => &IO::AIO::poll_cb); |
|
|
1646 | |
|
|
1647 | =back |
|
|
1648 | |
|
|
1649 | =head3 CONTROLLING THE NUMBER OF THREADS |
|
|
1650 | |
|
|
1651 | =over |
|
|
1652 | |
|
|
1653 | =item IO::AIO::min_parallel $nthreads |
|
|
1654 | |
|
|
1655 | Set the minimum number of AIO threads to C<$nthreads>. The current |
|
|
1656 | default is C<8>, which means eight asynchronous operations can execute |
|
|
1657 | concurrently at any one time (the number of outstanding requests, |
|
|
1658 | however, is unlimited). |
|
|
1659 | |
|
|
1660 | IO::AIO starts threads only on demand, when an AIO request is queued and |
|
|
1661 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
1662 | create demand for a hundred threads, even if it turns out that everything |
|
|
1663 | is in the cache and could have been processed faster by a single thread. |
|
|
1664 | |
|
|
1665 | It is recommended to keep the number of threads relatively low, as some |
|
|
1666 | Linux kernel versions will scale negatively with the number of threads |
|
|
1667 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
|
|
1668 | versions, 4-32 threads should be fine. |
|
|
1669 | |
|
|
1670 | Under most circumstances you don't need to call this function, as the |
|
|
1671 | module selects a default that is suitable for low to moderate load. |
|
|
1672 | |
|
|
1673 | =item IO::AIO::max_parallel $nthreads |
|
|
1674 | |
|
|
1675 | Sets the maximum number of AIO threads to C<$nthreads>. If more than the |
|
|
1676 | specified number of threads are currently running, this function kills |
|
|
1677 | them. This function blocks until the limit is reached. |
|
|
1678 | |
|
|
1679 | While C<$nthreads> are zero, aio requests get queued but not executed |
|
|
1680 | until the number of threads has been increased again. |
|
|
1681 | |
|
|
1682 | This module automatically runs C<max_parallel 0> at program end, to ensure |
|
|
1683 | that all threads are killed and that there are no outstanding requests. |
|
|
1684 | |
|
|
1685 | Under normal circumstances you don't need to call this function. |
|
|
1686 | |
|
|
1687 | =item IO::AIO::max_idle $nthreads |
|
|
1688 | |
|
|
1689 | Limit the number of threads (default: 4) that are allowed to idle |
|
|
1690 | (i.e., threads that did not get a request to process within the idle |
|
|
1691 | timeout (default: 10 seconds). That means if a thread becomes idle while |
|
|
1692 | C<$nthreads> other threads are also idle, it will free its resources and |
|
|
1693 | exit. |
|
|
1694 | |
|
|
1695 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1696 | to allow for extremely high load situations, but want to free resources |
|
|
1697 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1698 | |
|
|
1699 | The default is probably ok in most situations, especially if thread |
|
|
1700 | creation is fast. If thread creation is very slow on your system you might |
|
|
1701 | want to use larger values. |
|
|
1702 | |
|
|
1703 | =item IO::AIO::idle_timeout $seconds |
|
|
1704 | |
|
|
1705 | Sets the minimum idle timeout (default 10) after which worker threads are |
|
|
1706 | allowed to exit. SEe C<IO::AIO::max_idle>. |
|
|
1707 | |
|
|
1708 | =item IO::AIO::max_outstanding $maxreqs |
|
|
1709 | |
|
|
1710 | Sets the maximum number of outstanding requests to C<$nreqs>. If |
|
|
1711 | you do queue up more than this number of requests, the next call to |
|
|
1712 | C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as |
|
|
1713 | C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no |
|
|
1714 | longer exceeded. |
|
|
1715 | |
|
|
1716 | In other words, this setting does not enforce a queue limit, but can be |
|
|
1717 | used to make poll functions block if the limit is exceeded. |
|
|
1718 | |
|
|
1719 | This is a very bad function to use in interactive programs because it |
|
|
1720 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1721 | use an C<aio_group> together with a feed callback. |
|
|
1722 | |
|
|
1723 | It's main use is in scripts without an event loop - when you want to stat |
|
|
1724 | a lot of files, you can write somehting like this: |
|
|
1725 | |
|
|
1726 | IO::AIO::max_outstanding 32; |
|
|
1727 | |
|
|
1728 | for my $path (...) { |
|
|
1729 | aio_stat $path , ...; |
|
|
1730 | IO::AIO::poll_cb; |
|
|
1731 | } |
|
|
1732 | |
|
|
1733 | IO::AIO::flush; |
|
|
1734 | |
|
|
1735 | The call to C<poll_cb> inside the loop will normally return instantly, but |
|
|
1736 | as soon as more thna C<32> reqeusts are in-flight, it will block until |
|
|
1737 | some requests have been handled. This keeps the loop from pushing a large |
|
|
1738 | number of C<aio_stat> requests onto the queue. |
|
|
1739 | |
|
|
1740 | The default value for C<max_outstanding> is very large, so there is no |
|
|
1741 | practical limit on the number of outstanding requests. |
|
|
1742 | |
|
|
1743 | =back |
|
|
1744 | |
|
|
1745 | =head3 STATISTICAL INFORMATION |
|
|
1746 | |
|
|
1747 | =over |
|
|
1748 | |
238 | =item IO::AIO::flush |
1749 | =item IO::AIO::nreqs |
239 | |
1750 | |
240 | Wait till all outstanding AIO requests have been handled. |
1751 | Returns the number of requests currently in the ready, execute or pending |
|
|
1752 | states (i.e. for which their callback has not been invoked yet). |
241 | |
1753 | |
242 | Strictly equivalent to: |
1754 | Example: wait till there are no outstanding requests anymore: |
243 | |
1755 | |
244 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1756 | IO::AIO::poll_wait, IO::AIO::poll_cb |
245 | while IO::AIO::nreqs; |
1757 | while IO::AIO::nreqs; |
246 | |
1758 | |
|
|
1759 | =item IO::AIO::nready |
|
|
1760 | |
|
|
1761 | Returns the number of requests currently in the ready state (not yet |
|
|
1762 | executed). |
|
|
1763 | |
247 | =item IO::AIO::poll |
1764 | =item IO::AIO::npending |
248 | |
1765 | |
249 | Waits until some requests have been handled. |
1766 | Returns the number of requests currently in the pending state (executed, |
250 | |
1767 | but not yet processed by poll_cb). |
251 | Strictly equivalent to: |
|
|
252 | |
|
|
253 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
254 | if IO::AIO::nreqs; |
|
|
255 | |
|
|
256 | =item IO::AIO::min_parallel $nthreads |
|
|
257 | |
|
|
258 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
|
|
259 | C<1>, which means a single asynchronous operation can be done at one time |
|
|
260 | (the number of outstanding operations, however, is unlimited). |
|
|
261 | |
|
|
262 | It is recommended to keep the number of threads low, as some Linux |
|
|
263 | kernel versions will scale negatively with the number of threads (higher |
|
|
264 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
|
|
265 | threads should be fine. |
|
|
266 | |
|
|
267 | Under normal circumstances you don't need to call this function, as this |
|
|
268 | module automatically starts some threads (the exact number might change, |
|
|
269 | and is currently 4). |
|
|
270 | |
|
|
271 | =item IO::AIO::max_parallel $nthreads |
|
|
272 | |
|
|
273 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
|
|
274 | the specified number of threads are currently running, kill them. This |
|
|
275 | function blocks until the limit is reached. |
|
|
276 | |
|
|
277 | This module automatically runs C<max_parallel 0> at program end, to ensure |
|
|
278 | that all threads are killed and that there are no outstanding requests. |
|
|
279 | |
|
|
280 | Under normal circumstances you don't need to call this function. |
|
|
281 | |
|
|
282 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
|
|
283 | |
|
|
284 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
|
|
285 | try to queue up more than this number of requests, the caller will block until |
|
|
286 | some requests have been handled. |
|
|
287 | |
|
|
288 | The default is very large, so normally there is no practical limit. If you |
|
|
289 | queue up many requests in a loop it it often improves speed if you set |
|
|
290 | this to a relatively low number, such as C<100>. |
|
|
291 | |
|
|
292 | Under normal circumstances you don't need to call this function. |
|
|
293 | |
1768 | |
294 | =back |
1769 | =back |
295 | |
1770 | |
|
|
1771 | =head3 MISCELLANEOUS FUNCTIONS |
|
|
1772 | |
|
|
1773 | IO::AIO implements some functions that might be useful, but are not |
|
|
1774 | asynchronous. |
|
|
1775 | |
|
|
1776 | =over 4 |
|
|
1777 | |
|
|
1778 | =item IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
1779 | |
|
|
1780 | Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, |
|
|
1781 | but is blocking (this makes most sense if you know the input data is |
|
|
1782 | likely cached already and the output filehandle is set to non-blocking |
|
|
1783 | operations). |
|
|
1784 | |
|
|
1785 | Returns the number of bytes copied, or C<-1> on error. |
|
|
1786 | |
|
|
1787 | =item IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
1788 | |
|
|
1789 | Simply calls the C<posix_fadvise> function (see its |
|
|
1790 | manpage for details). The following advice constants are |
|
|
1791 | available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, |
|
|
1792 | C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, |
|
|
1793 | C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. |
|
|
1794 | |
|
|
1795 | On systems that do not implement C<posix_fadvise>, this function returns |
|
|
1796 | ENOSYS, otherwise the return value of C<posix_fadvise>. |
|
|
1797 | |
|
|
1798 | =item IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1799 | |
|
|
1800 | Simply calls the C<posix_madvise> function (see its |
|
|
1801 | manpage for details). The following advice constants are |
|
|
1802 | available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, |
|
|
1803 | C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. |
|
|
1804 | |
|
|
1805 | On systems that do not implement C<posix_madvise>, this function returns |
|
|
1806 | ENOSYS, otherwise the return value of C<posix_madvise>. |
|
|
1807 | |
|
|
1808 | =item IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1809 | |
|
|
1810 | Simply calls the C<mprotect> function on the preferably AIO::mmap'ed |
|
|
1811 | $scalar (see its manpage for details). The following protect |
|
|
1812 | constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, |
|
|
1813 | C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. |
|
|
1814 | |
|
|
1815 | On systems that do not implement C<mprotect>, this function returns |
|
|
1816 | ENOSYS, otherwise the return value of C<mprotect>. |
|
|
1817 | |
|
|
1818 | =item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1819 | |
|
|
1820 | Memory-maps a file (or anonymous memory range) and attaches it to the |
|
|
1821 | given C<$scalar>, which will act like a string scalar. |
|
|
1822 | |
|
|
1823 | The only operations allowed on the scalar are C<substr>/C<vec> that don't |
|
|
1824 | change the string length, and most read-only operations such as copying it |
|
|
1825 | or searching it with regexes and so on. |
|
|
1826 | |
|
|
1827 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1828 | |
|
|
1829 | The memory map associated with the C<$scalar> is automatically removed |
|
|
1830 | when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or |
|
|
1831 | C<IO::AIO::munmap> functions are called. |
|
|
1832 | |
|
|
1833 | This calls the C<mmap>(2) function internally. See your system's manual |
|
|
1834 | page for details on the C<$length>, C<$prot> and C<$flags> parameters. |
|
|
1835 | |
|
|
1836 | The C<$length> must be larger than zero and smaller than the actual |
|
|
1837 | filesize. |
|
|
1838 | |
|
|
1839 | C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, |
|
|
1840 | C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, |
|
|
1841 | |
|
|
1842 | C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or |
|
|
1843 | C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when |
|
|
1844 | not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> |
|
|
1845 | (which is set to C<MAP_ANON> if your system only provides this |
|
|
1846 | constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, |
|
|
1847 | C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or |
|
|
1848 | C<IO::AIO::MAP_NONBLOCK> |
|
|
1849 | |
|
|
1850 | If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. |
|
|
1851 | |
|
|
1852 | C<$offset> is the offset from the start of the file - it generally must be |
|
|
1853 | a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. |
|
|
1854 | |
|
|
1855 | Example: |
|
|
1856 | |
|
|
1857 | use Digest::MD5; |
|
|
1858 | use IO::AIO; |
|
|
1859 | |
|
|
1860 | open my $fh, "<verybigfile" |
|
|
1861 | or die "$!"; |
|
|
1862 | |
|
|
1863 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1864 | or die "verybigfile: $!"; |
|
|
1865 | |
|
|
1866 | my $fast_md5 = md5 $data; |
|
|
1867 | |
|
|
1868 | =item IO::AIO::munmap $scalar |
|
|
1869 | |
|
|
1870 | Removes a previous mmap and undefines the C<$scalar>. |
|
|
1871 | |
|
|
1872 | =item IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1873 | |
|
|
1874 | Calls the C<munlock> function, undoing the effects of a previous |
|
|
1875 | C<aio_mlock> call (see its description for details). |
|
|
1876 | |
|
|
1877 | =item IO::AIO::munlockall |
|
|
1878 | |
|
|
1879 | Calls the C<munlockall> function. |
|
|
1880 | |
|
|
1881 | On systems that do not implement C<munlockall>, this function returns |
|
|
1882 | ENOSYS, otherwise the return value of C<munlockall>. |
|
|
1883 | |
|
|
1884 | =back |
|
|
1885 | |
296 | =cut |
1886 | =cut |
297 | |
1887 | |
298 | # support function to convert a fd into a perl filehandle |
|
|
299 | sub _fd2fh { |
|
|
300 | return undef if $_[0] < 0; |
|
|
301 | |
|
|
302 | # try to be perl5.6-compatible |
|
|
303 | local *AIO_FH; |
|
|
304 | open AIO_FH, "+<&=$_[0]" |
|
|
305 | or return undef; |
|
|
306 | |
|
|
307 | *AIO_FH |
|
|
308 | } |
|
|
309 | |
|
|
310 | min_parallel 4; |
1888 | min_parallel 8; |
311 | |
1889 | |
312 | END { |
1890 | END { flush } |
313 | max_parallel 0; |
|
|
314 | } |
|
|
315 | |
1891 | |
316 | 1; |
1892 | 1; |
317 | |
1893 | |
|
|
1894 | =head1 EVENT LOOP INTEGRATION |
|
|
1895 | |
|
|
1896 | It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO |
|
|
1897 | automatically into many event loops: |
|
|
1898 | |
|
|
1899 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
1900 | use AnyEvent::AIO; |
|
|
1901 | |
|
|
1902 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
1903 | some examples of how to do this: |
|
|
1904 | |
|
|
1905 | # EV integration |
|
|
1906 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
1907 | |
|
|
1908 | # Event integration |
|
|
1909 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1910 | poll => 'r', |
|
|
1911 | cb => \&IO::AIO::poll_cb); |
|
|
1912 | |
|
|
1913 | # Glib/Gtk2 integration |
|
|
1914 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
1915 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
1916 | |
|
|
1917 | # Tk integration |
|
|
1918 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
1919 | readable => \&IO::AIO::poll_cb); |
|
|
1920 | |
|
|
1921 | # Danga::Socket integration |
|
|
1922 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
1923 | \&IO::AIO::poll_cb); |
|
|
1924 | |
|
|
1925 | =head2 FORK BEHAVIOUR |
|
|
1926 | |
|
|
1927 | Usage of pthreads in a program changes the semantics of fork |
|
|
1928 | considerably. Specifically, only async-safe functions can be called after |
|
|
1929 | fork. Perl doesn't know about this, so in general, you cannot call fork |
|
|
1930 | with defined behaviour in perl if pthreads are involved. IO::AIO uses |
|
|
1931 | pthreads, so this applies, but many other extensions and (for inexplicable |
|
|
1932 | reasons) perl itself often is linked against pthreads, so this limitation |
|
|
1933 | applies to quite a lot of perls. |
|
|
1934 | |
|
|
1935 | This module no longer tries to fight your OS, or POSIX. That means IO::AIO |
|
|
1936 | only works in the process that loaded it. Forking is fully supported, but |
|
|
1937 | using IO::AIO in the child is not. |
|
|
1938 | |
|
|
1939 | You might get around by not I<using> IO::AIO before (or after) |
|
|
1940 | forking. You could also try to call the L<IO::AIO::reinit> function in the |
|
|
1941 | child: |
|
|
1942 | |
|
|
1943 | =over 4 |
|
|
1944 | |
|
|
1945 | =item IO::AIO::reinit |
|
|
1946 | |
|
|
1947 | Abandons all current requests and I/O threads and simply reinitialises all |
|
|
1948 | data structures. This is not an operation supported by any standards, but |
|
|
1949 | happens to work on GNU/Linux and some newer BSD systems. |
|
|
1950 | |
|
|
1951 | The only reasonable use for this function is to call it after forking, if |
|
|
1952 | C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in |
|
|
1953 | the process will result in undefined behaviour. Calling it at any time |
|
|
1954 | will also result in any undefined (by POSIX) behaviour. |
|
|
1955 | |
|
|
1956 | =back |
|
|
1957 | |
|
|
1958 | =head2 MEMORY USAGE |
|
|
1959 | |
|
|
1960 | Per-request usage: |
|
|
1961 | |
|
|
1962 | Each aio request uses - depending on your architecture - around 100-200 |
|
|
1963 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
|
|
1964 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
|
|
1965 | scalars and other data passed into aio requests will also be locked and |
|
|
1966 | will consume memory till the request has entered the done state. |
|
|
1967 | |
|
|
1968 | This is not awfully much, so queuing lots of requests is not usually a |
|
|
1969 | problem. |
|
|
1970 | |
|
|
1971 | Per-thread usage: |
|
|
1972 | |
|
|
1973 | In the execution phase, some aio requests require more memory for |
|
|
1974 | temporary buffers, and each thread requires a stack and other data |
|
|
1975 | structures (usually around 16k-128k, depending on the OS). |
|
|
1976 | |
|
|
1977 | =head1 KNOWN BUGS |
|
|
1978 | |
|
|
1979 | Known bugs will be fixed in the next release. |
|
|
1980 | |
318 | =head1 SEE ALSO |
1981 | =head1 SEE ALSO |
319 | |
1982 | |
320 | L<Coro>, L<Linux::AIO>. |
1983 | L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a |
|
|
1984 | more natural syntax. |
321 | |
1985 | |
322 | =head1 AUTHOR |
1986 | =head1 AUTHOR |
323 | |
1987 | |
324 | Marc Lehmann <schmorp@schmorp.de> |
1988 | Marc Lehmann <schmorp@schmorp.de> |
325 | http://home.schmorp.de/ |
1989 | http://home.schmorp.de/ |