… | |
… | |
50 | |
50 | |
51 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
52 | |
52 | |
53 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. |
54 | operating system supports. |
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55 | |
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56 | Asynchronous means that operations that can normally block your program |
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57 | (e.g. reading from disk) will be done asynchronously: the operation |
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58 | will still block, but you can do something else in the meantime. This |
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59 | is extremely useful for programs that need to stay interactive even |
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60 | when doing heavy I/O (GUI programs, high performance network servers |
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61 | etc.), but can also be used to easily do operations in parallel that are |
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62 | normally done sequentially, e.g. stat'ing many files, which is much faster |
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63 | on a RAID volume or over NFS when you do a number of stat operations |
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64 | concurrently. |
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65 | |
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66 | While this works on all types of file descriptors (for example sockets), |
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67 | using these functions on file descriptors that support nonblocking |
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68 | operation (again, sockets, pipes etc.) is very inefficient. Use an event |
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69 | loop for that (such as the L<Event|Event> module): IO::AIO will naturally |
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70 | fit into such an event loop itself. |
55 | |
71 | |
56 | In this version, a number of threads are started that execute your |
72 | In this version, a number of threads are started that execute your |
57 | requests and signal their completion. You don't need thread support |
73 | requests and signal their completion. You don't need thread support |
58 | in perl, and the threads created by this module will not be visible |
74 | in perl, and the threads created by this module will not be visible |
59 | to perl. In the future, this module might make use of the native aio |
75 | to perl. In the future, this module might make use of the native aio |
60 | functions available on many operating systems. However, they are often |
76 | functions available on many operating systems. However, they are often |
61 | not well-supported or restricted (Linux doesn't allow them on normal |
77 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
62 | files currently, for example), and they would only support aio_read and |
78 | files currently, for example), and they would only support aio_read and |
63 | aio_write, so the remaining functionality would have to be implemented |
79 | aio_write, so the remaining functionality would have to be implemented |
64 | using threads anyway. |
80 | using threads anyway. |
65 | |
81 | |
66 | Although the module will work with in the presence of other (Perl-) |
82 | Although the module will work with in the presence of other (Perl-) |
67 | threads, it is currently not reentrant in any way, so use appropriate |
83 | threads, it is currently not reentrant in any way, so use appropriate |
68 | locking yourself, always call C<poll_cb> from within the same thread, or |
84 | locking yourself, always call C<poll_cb> from within the same thread, or |
69 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
85 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
70 | |
86 | |
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87 | =head2 EXAMPLE |
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88 | |
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89 | This is a simple example that uses the Event module and loads |
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90 | F</etc/passwd> asynchronously: |
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91 | |
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92 | use Fcntl; |
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93 | use Event; |
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94 | use IO::AIO; |
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95 | |
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96 | # register the IO::AIO callback with Event |
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97 | Event->io (fd => IO::AIO::poll_fileno, |
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98 | poll => 'r', |
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99 | cb => \&IO::AIO::poll_cb); |
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100 | |
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101 | # queue the request to open /etc/passwd |
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102 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
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103 | my $fh = $_[0] |
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104 | or die "error while opening: $!"; |
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105 | |
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106 | # stat'ing filehandles is generally non-blocking |
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107 | my $size = -s $fh; |
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108 | |
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109 | # queue a request to read the file |
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110 | my $contents; |
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111 | aio_read $fh, 0, $size, $contents, 0, sub { |
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112 | $_[0] == $size |
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113 | or die "short read: $!"; |
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114 | |
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115 | close $fh; |
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116 | |
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117 | # file contents now in $contents |
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118 | print $contents; |
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119 | |
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120 | # exit event loop and program |
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121 | Event::unloop; |
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122 | }; |
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123 | }; |
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124 | |
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125 | # possibly queue up other requests, or open GUI windows, |
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126 | # check for sockets etc. etc. |
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127 | |
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128 | # process events as long as there are some: |
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129 | Event::loop; |
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130 | |
71 | =head1 REQUEST ANATOMY AND LIFETIME |
131 | =head1 REQUEST ANATOMY AND LIFETIME |
72 | |
132 | |
73 | Every C<aio_*> function creates a request. which is a C data structure not |
133 | Every C<aio_*> function creates a request. which is a C data structure not |
74 | directly visible to Perl. |
134 | directly visible to Perl. |
75 | |
135 | |
… | |
… | |
116 | Request has reached the end of its lifetime and holds no resources anymore |
176 | Request has reached the end of its lifetime and holds no resources anymore |
117 | (except possibly for the Perl object, but its connection to the actual |
177 | (except possibly for the Perl object, but its connection to the actual |
118 | aio request is severed and calling its methods will either do nothing or |
178 | aio request is severed and calling its methods will either do nothing or |
119 | result in a runtime error). |
179 | result in a runtime error). |
120 | |
180 | |
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181 | =back |
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182 | |
121 | =cut |
183 | =cut |
122 | |
184 | |
123 | package IO::AIO; |
185 | package IO::AIO; |
124 | |
186 | |
125 | no warnings; |
187 | no warnings; |
126 | use strict 'vars'; |
188 | use strict 'vars'; |
127 | |
189 | |
128 | use base 'Exporter'; |
190 | use base 'Exporter'; |
129 | |
191 | |
130 | BEGIN { |
192 | BEGIN { |
131 | our $VERSION = '2.0'; |
193 | our $VERSION = '2.1'; |
132 | |
194 | |
133 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
195 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
134 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
196 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
135 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
197 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
136 | aio_group aio_nop); |
198 | aio_copy aio_group aio_nop aio_mknod); |
137 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
199 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
138 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
200 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
139 | min_parallel max_parallel nreqs); |
201 | min_parallel max_parallel max_idle |
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202 | nreqs nready npending nthreads |
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203 | max_poll_time max_poll_reqs); |
140 | |
204 | |
141 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
205 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
142 | |
206 | |
143 | require XSLoader; |
207 | require XSLoader; |
144 | XSLoader::load ("IO::AIO", $VERSION); |
208 | XSLoader::load ("IO::AIO", $VERSION); |
145 | } |
209 | } |
146 | |
210 | |
147 | =head1 FUNCTIONS |
211 | =head1 FUNCTIONS |
148 | |
212 | |
149 | =head2 AIO FUNCTIONS |
213 | =head2 AIO REQUEST FUNCTIONS |
150 | |
214 | |
151 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
215 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
152 | with the same name (sans C<aio_>). The arguments are similar or identical, |
216 | with the same name (sans C<aio_>). The arguments are similar or identical, |
153 | and they all accept an additional (and optional) C<$callback> argument |
217 | and they all accept an additional (and optional) C<$callback> argument |
154 | which must be a code reference. This code reference will get called with |
218 | which must be a code reference. This code reference will get called with |
… | |
… | |
157 | syscall has been executed asynchronously. |
221 | syscall has been executed asynchronously. |
158 | |
222 | |
159 | All functions expecting a filehandle keep a copy of the filehandle |
223 | All functions expecting a filehandle keep a copy of the filehandle |
160 | internally until the request has finished. |
224 | internally until the request has finished. |
161 | |
225 | |
162 | All requests return objects of type L<IO::AIO::REQ> that allow further |
226 | All functions return request objects of type L<IO::AIO::REQ> that allow |
163 | manipulation of those requests while they are in-flight. |
227 | further manipulation of those requests while they are in-flight. |
164 | |
228 | |
165 | The pathnames you pass to these routines I<must> be absolute and |
229 | The pathnames you pass to these routines I<must> be absolute and |
166 | encoded in byte form. The reason for the former is that at the time the |
230 | encoded as octets. The reason for the former is that at the time the |
167 | request is being executed, the current working directory could have |
231 | request is being executed, the current working directory could have |
168 | changed. Alternatively, you can make sure that you never change the |
232 | changed. Alternatively, you can make sure that you never change the |
169 | current working directory. |
233 | current working directory anywhere in the program and then use relative |
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234 | paths. |
170 | |
235 | |
171 | To encode pathnames to byte form, either make sure you either: a) |
236 | To encode pathnames as octets, either make sure you either: a) always pass |
172 | always pass in filenames you got from outside (command line, readdir |
237 | in filenames you got from outside (command line, readdir etc.) without |
173 | etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
238 | tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
174 | your pathnames to the locale (or other) encoding in effect in the user |
239 | your pathnames to the locale (or other) encoding in effect in the user |
175 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
240 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
176 | use something else. |
241 | use something else to ensure your scalar has the correct contents. |
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242 | |
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243 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
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244 | handles correctly wether it is set or not. |
177 | |
245 | |
178 | =over 4 |
246 | =over 4 |
179 | |
247 | |
180 | =item aioreq_pri $pri |
248 | =item $prev_pri = aioreq_pri [$pri] |
181 | |
249 | |
182 | Sets the priority for the next aio request. The default priority |
250 | Returns the priority value that would be used for the next request and, if |
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251 | C<$pri> is given, sets the priority for the next aio request. |
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252 | |
183 | is C<0>, the minimum and maximum priorities are C<-4> and C<4>, |
253 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
184 | respectively. Requests with higher priority will be serviced first. |
254 | and C<4>, respectively. Requests with higher priority will be serviced |
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255 | first. |
185 | |
256 | |
186 | The priority will be reset to C<0> after each call to one of the C<aio_> |
257 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
187 | functions. |
258 | functions. |
188 | |
259 | |
189 | Example: open a file with low priority, then read something from it with |
260 | Example: open a file with low priority, then read something from it with |
190 | higher priority so the read request is serviced before other low priority |
261 | higher priority so the read request is serviced before other low priority |
191 | open requests (potentially spamming the cache): |
262 | open requests (potentially spamming the cache): |
… | |
… | |
201 | }; |
272 | }; |
202 | |
273 | |
203 | =item aioreq_nice $pri_adjust |
274 | =item aioreq_nice $pri_adjust |
204 | |
275 | |
205 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
276 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
206 | priority, so effects are cumulative. |
277 | priority, so the effect is cumulative. |
207 | |
278 | |
208 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
279 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
209 | |
280 | |
210 | Asynchronously open or create a file and call the callback with a newly |
281 | Asynchronously open or create a file and call the callback with a newly |
211 | created filehandle for the file. |
282 | created filehandle for the file. |
… | |
… | |
261 | |
332 | |
262 | aio_read $fh, 7, 15, $buffer, 0, sub { |
333 | aio_read $fh, 7, 15, $buffer, 0, sub { |
263 | $_[0] > 0 or die "read error: $!"; |
334 | $_[0] > 0 or die "read error: $!"; |
264 | print "read $_[0] bytes: <$buffer>\n"; |
335 | print "read $_[0] bytes: <$buffer>\n"; |
265 | }; |
336 | }; |
266 | |
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267 | =item aio_move $srcpath, $dstpath, $callback->($status) |
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268 | |
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269 | Try to move the I<file> (directories not supported as either source or |
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270 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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271 | the C<0> (error) or C<-1> ok. |
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272 | |
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273 | This is a composite request that tries to rename(2) the file first. If |
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274 | rename files with C<EXDEV>, it creates the destination file with mode 0200 |
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275 | and copies the contents of the source file into it using C<aio_sendfile>, |
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276 | followed by restoring atime, mtime, access mode and uid/gid, in that |
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277 | order, and unlinking the C<$srcpath>. |
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278 | |
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279 | If an error occurs, the partial destination file will be unlinked, if |
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280 | possible, except when setting atime, mtime, access mode and uid/gid, where |
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281 | errors are being ignored. |
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282 | |
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283 | =cut |
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284 | |
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285 | sub aio_move($$$) { |
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286 | my ($src, $dst, $cb) = @_; |
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287 | |
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288 | my $grp = aio_group $cb; |
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289 | |
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290 | add $grp aio_rename $src, $dst, sub { |
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291 | if ($_[0] && $! == EXDEV) { |
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292 | add $grp aio_open $src, O_RDONLY, 0, sub { |
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293 | if (my $src_fh = $_[0]) { |
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294 | my @stat = stat $src_fh; |
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295 | |
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296 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
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297 | if (my $dst_fh = $_[0]) { |
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298 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
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299 | close $src_fh; |
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300 | |
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301 | if ($_[0] == $stat[7]) { |
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302 | utime $stat[8], $stat[9], $dst; |
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303 | chmod $stat[2] & 07777, $dst_fh; |
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304 | chown $stat[4], $stat[5], $dst_fh; |
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305 | close $dst_fh; |
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306 | |
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307 | add $grp aio_unlink $src, sub { |
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308 | $grp->result ($_[0]); |
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309 | }; |
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310 | } else { |
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311 | my $errno = $!; |
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312 | add $grp aio_unlink $dst, sub { |
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313 | $! = $errno; |
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314 | $grp->result (-1); |
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315 | }; |
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316 | } |
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317 | }; |
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318 | } else { |
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319 | $grp->result (-1); |
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320 | } |
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321 | }, |
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322 | |
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323 | } else { |
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324 | $grp->result (-1); |
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325 | } |
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326 | }; |
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327 | } else { |
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328 | $grp->result ($_[0]); |
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329 | } |
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330 | }; |
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331 | |
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332 | $grp |
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333 | } |
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334 | |
337 | |
335 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
338 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
336 | |
339 | |
337 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
340 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
338 | reading at byte offset C<$in_offset>, and starts writing at the current |
341 | reading at byte offset C<$in_offset>, and starts writing at the current |
… | |
… | |
394 | =item aio_unlink $pathname, $callback->($status) |
397 | =item aio_unlink $pathname, $callback->($status) |
395 | |
398 | |
396 | Asynchronously unlink (delete) a file and call the callback with the |
399 | Asynchronously unlink (delete) a file and call the callback with the |
397 | result code. |
400 | result code. |
398 | |
401 | |
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402 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
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403 | |
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404 | [EXPERIMENTAL] |
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405 | |
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406 | Asynchronously create a device node (or fifo). See mknod(2). |
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407 | |
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408 | The only (POSIX-) portable way of calling this function is: |
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409 | |
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410 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
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411 | |
399 | =item aio_link $srcpath, $dstpath, $callback->($status) |
412 | =item aio_link $srcpath, $dstpath, $callback->($status) |
400 | |
413 | |
401 | Asynchronously create a new link to the existing object at C<$srcpath> at |
414 | Asynchronously create a new link to the existing object at C<$srcpath> at |
402 | the path C<$dstpath> and call the callback with the result code. |
415 | the path C<$dstpath> and call the callback with the result code. |
403 | |
416 | |
… | |
… | |
422 | directory (i.e. opendir + readdir + closedir). The entries will not be |
435 | directory (i.e. opendir + readdir + closedir). The entries will not be |
423 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
436 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
424 | |
437 | |
425 | The callback a single argument which is either C<undef> or an array-ref |
438 | The callback a single argument which is either C<undef> or an array-ref |
426 | with the filenames. |
439 | with the filenames. |
|
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440 | |
|
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441 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
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442 | |
|
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443 | Try to copy the I<file> (directories not supported as either source or |
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444 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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445 | the C<0> (error) or C<-1> ok. |
|
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446 | |
|
|
447 | This is a composite request that it creates the destination file with |
|
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448 | mode 0200 and copies the contents of the source file into it using |
|
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449 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
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450 | uid/gid, in that order. |
|
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451 | |
|
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452 | If an error occurs, the partial destination file will be unlinked, if |
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453 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
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454 | errors are being ignored. |
|
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455 | |
|
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456 | =cut |
|
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457 | |
|
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458 | sub aio_copy($$;$) { |
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459 | my ($src, $dst, $cb) = @_; |
|
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460 | |
|
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461 | my $pri = aioreq_pri; |
|
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462 | my $grp = aio_group $cb; |
|
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463 | |
|
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464 | aioreq_pri $pri; |
|
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465 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
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466 | if (my $src_fh = $_[0]) { |
|
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467 | my @stat = stat $src_fh; |
|
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468 | |
|
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469 | aioreq_pri $pri; |
|
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470 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
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471 | if (my $dst_fh = $_[0]) { |
|
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472 | aioreq_pri $pri; |
|
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473 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
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474 | if ($_[0] == $stat[7]) { |
|
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475 | $grp->result (0); |
|
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476 | close $src_fh; |
|
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477 | |
|
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478 | # those should not normally block. should. should. |
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479 | utime $stat[8], $stat[9], $dst; |
|
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480 | chmod $stat[2] & 07777, $dst_fh; |
|
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481 | chown $stat[4], $stat[5], $dst_fh; |
|
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482 | close $dst_fh; |
|
|
483 | } else { |
|
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484 | $grp->result (-1); |
|
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485 | close $src_fh; |
|
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486 | close $dst_fh; |
|
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487 | |
|
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488 | aioreq $pri; |
|
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489 | add $grp aio_unlink $dst; |
|
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490 | } |
|
|
491 | }; |
|
|
492 | } else { |
|
|
493 | $grp->result (-1); |
|
|
494 | } |
|
|
495 | }, |
|
|
496 | |
|
|
497 | } else { |
|
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498 | $grp->result (-1); |
|
|
499 | } |
|
|
500 | }; |
|
|
501 | |
|
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502 | $grp |
|
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503 | } |
|
|
504 | |
|
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505 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
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506 | |
|
|
507 | Try to move the I<file> (directories not supported as either source or |
|
|
508 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
509 | the C<0> (error) or C<-1> ok. |
|
|
510 | |
|
|
511 | This is a composite request that tries to rename(2) the file first. If |
|
|
512 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
513 | that is successful, unlinking the C<$srcpath>. |
|
|
514 | |
|
|
515 | =cut |
|
|
516 | |
|
|
517 | sub aio_move($$;$) { |
|
|
518 | my ($src, $dst, $cb) = @_; |
|
|
519 | |
|
|
520 | my $pri = aioreq_pri; |
|
|
521 | my $grp = aio_group $cb; |
|
|
522 | |
|
|
523 | aioreq_pri $pri; |
|
|
524 | add $grp aio_rename $src, $dst, sub { |
|
|
525 | if ($_[0] && $! == EXDEV) { |
|
|
526 | aioreq_pri $pri; |
|
|
527 | add $grp aio_copy $src, $dst, sub { |
|
|
528 | $grp->result ($_[0]); |
|
|
529 | |
|
|
530 | if (!$_[0]) { |
|
|
531 | aioreq_pri $pri; |
|
|
532 | add $grp aio_unlink $src; |
|
|
533 | } |
|
|
534 | }; |
|
|
535 | } else { |
|
|
536 | $grp->result ($_[0]); |
|
|
537 | } |
|
|
538 | }; |
|
|
539 | |
|
|
540 | $grp |
|
|
541 | } |
427 | |
542 | |
428 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
543 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
429 | |
544 | |
430 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
545 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
431 | efficiently separate the entries of directory C<$path> into two sets of |
546 | efficiently separate the entries of directory C<$path> into two sets of |
… | |
… | |
433 | recurse into (everything else, including symlinks to directories). |
548 | recurse into (everything else, including symlinks to directories). |
434 | |
549 | |
435 | C<aio_scandir> is a composite request that creates of many sub requests_ |
550 | C<aio_scandir> is a composite request that creates of many sub requests_ |
436 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
551 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
437 | this function generates. If it is C<< <= 0 >>, then a suitable default |
552 | this function generates. If it is C<< <= 0 >>, then a suitable default |
438 | will be chosen (currently 6). |
553 | will be chosen (currently 4). |
439 | |
554 | |
440 | On error, the callback is called without arguments, otherwise it receives |
555 | On error, the callback is called without arguments, otherwise it receives |
441 | two array-refs with path-relative entry names. |
556 | two array-refs with path-relative entry names. |
442 | |
557 | |
443 | Example: |
558 | Example: |
… | |
… | |
480 | =cut |
595 | =cut |
481 | |
596 | |
482 | sub aio_scandir($$$) { |
597 | sub aio_scandir($$$) { |
483 | my ($path, $maxreq, $cb) = @_; |
598 | my ($path, $maxreq, $cb) = @_; |
484 | |
599 | |
|
|
600 | my $pri = aioreq_pri; |
|
|
601 | |
485 | my $grp = aio_group $cb; |
602 | my $grp = aio_group $cb; |
486 | |
603 | |
487 | $maxreq = 6 if $maxreq <= 0; |
604 | $maxreq = 4 if $maxreq <= 0; |
488 | |
605 | |
489 | # stat once |
606 | # stat once |
|
|
607 | aioreq_pri $pri; |
490 | add $grp aio_stat $path, sub { |
608 | add $grp aio_stat $path, sub { |
491 | return $grp->result () if $_[0]; |
609 | return $grp->result () if $_[0]; |
492 | my $now = time; |
610 | my $now = time; |
493 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
611 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
494 | |
612 | |
495 | # read the directory entries |
613 | # read the directory entries |
|
|
614 | aioreq_pri $pri; |
496 | add $grp aio_readdir $path, sub { |
615 | add $grp aio_readdir $path, sub { |
497 | my $entries = shift |
616 | my $entries = shift |
498 | or return $grp->result (); |
617 | or return $grp->result (); |
499 | |
618 | |
500 | # stat the dir another time |
619 | # stat the dir another time |
|
|
620 | aioreq_pri $pri; |
501 | add $grp aio_stat $path, sub { |
621 | add $grp aio_stat $path, sub { |
502 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
622 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
503 | |
623 | |
504 | my $ndirs; |
624 | my $ndirs; |
505 | |
625 | |
… | |
… | |
529 | limit $statgrp $maxreq; |
649 | limit $statgrp $maxreq; |
530 | feed $statgrp sub { |
650 | feed $statgrp sub { |
531 | return unless @$entries; |
651 | return unless @$entries; |
532 | my $entry = pop @$entries; |
652 | my $entry = pop @$entries; |
533 | |
653 | |
|
|
654 | aioreq_pri $pri; |
534 | add $statgrp aio_stat "$path/$entry/.", sub { |
655 | add $statgrp aio_stat "$path/$entry/.", sub { |
535 | if ($_[0] < 0) { |
656 | if ($_[0] < 0) { |
536 | push @nondirs, $entry; |
657 | push @nondirs, $entry; |
537 | } else { |
658 | } else { |
538 | # need to check for real directory |
659 | # need to check for real directory |
|
|
660 | aioreq_pri $pri; |
539 | add $statgrp aio_lstat "$path/$entry", sub { |
661 | add $statgrp aio_lstat "$path/$entry", sub { |
540 | if (-d _) { |
662 | if (-d _) { |
541 | push @dirs, $entry; |
663 | push @dirs, $entry; |
542 | |
664 | |
543 | unless (--$ndirs) { |
665 | unless (--$ndirs) { |
… | |
… | |
714 | itself. Useful when you queued a lot of events but got a result early. |
836 | itself. Useful when you queued a lot of events but got a result early. |
715 | |
837 | |
716 | =item $grp->result (...) |
838 | =item $grp->result (...) |
717 | |
839 | |
718 | Set the result value(s) that will be passed to the group callback when all |
840 | Set the result value(s) that will be passed to the group callback when all |
719 | subrequests have finished. By default, no argument will be passed. |
841 | subrequests have finished and set thre groups errno to the current value |
|
|
842 | of errno (just like calling C<errno> without an error number). By default, |
|
|
843 | no argument will be passed and errno is zero. |
|
|
844 | |
|
|
845 | =item $grp->errno ([$errno]) |
|
|
846 | |
|
|
847 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
848 | when the argument is missing. |
|
|
849 | |
|
|
850 | Every aio request has an associated errno value that is restored when |
|
|
851 | the callback is invoked. This method lets you change this value from its |
|
|
852 | default (0). |
|
|
853 | |
|
|
854 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
855 | before the call to C<result>, or call c<errno> after it. |
720 | |
856 | |
721 | =item feed $grp $callback->($grp) |
857 | =item feed $grp $callback->($grp) |
722 | |
858 | |
723 | Sets a feeder/generator on this group: every group can have an attached |
859 | Sets a feeder/generator on this group: every group can have an attached |
724 | generator that generates requests if idle. The idea behind this is that, |
860 | generator that generates requests if idle. The idea behind this is that, |
… | |
… | |
763 | |
899 | |
764 | =back |
900 | =back |
765 | |
901 | |
766 | =head2 SUPPORT FUNCTIONS |
902 | =head2 SUPPORT FUNCTIONS |
767 | |
903 | |
|
|
904 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
905 | |
768 | =over 4 |
906 | =over 4 |
769 | |
907 | |
770 | =item $fileno = IO::AIO::poll_fileno |
908 | =item $fileno = IO::AIO::poll_fileno |
771 | |
909 | |
772 | Return the I<request result pipe file descriptor>. This filehandle must be |
910 | Return the I<request result pipe file descriptor>. This filehandle must be |
… | |
… | |
776 | |
914 | |
777 | See C<poll_cb> for an example. |
915 | See C<poll_cb> for an example. |
778 | |
916 | |
779 | =item IO::AIO::poll_cb |
917 | =item IO::AIO::poll_cb |
780 | |
918 | |
781 | Process all outstanding events on the result pipe. You have to call this |
919 | Process some outstanding events on the result pipe. You have to call this |
782 | regularly. Returns the number of events processed. Returns immediately |
920 | regularly. Returns the number of events processed. Returns immediately |
783 | when no events are outstanding. |
921 | when no events are outstanding. The amount of events processed depends on |
|
|
922 | the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. |
784 | |
923 | |
785 | If not all requests were processed for whatever reason, the filehandle |
924 | If not all requests were processed for whatever reason, the filehandle |
786 | will still be ready when C<poll_cb> returns. |
925 | will still be ready when C<poll_cb> returns. |
787 | |
926 | |
788 | Example: Install an Event watcher that automatically calls |
927 | Example: Install an Event watcher that automatically calls |
… | |
… | |
790 | |
929 | |
791 | Event->io (fd => IO::AIO::poll_fileno, |
930 | Event->io (fd => IO::AIO::poll_fileno, |
792 | poll => 'r', async => 1, |
931 | poll => 'r', async => 1, |
793 | cb => \&IO::AIO::poll_cb); |
932 | cb => \&IO::AIO::poll_cb); |
794 | |
933 | |
795 | =item IO::AIO::poll_some $max_requests |
934 | =item IO::AIO::max_poll_reqs $nreqs |
796 | |
935 | |
797 | Similar to C<poll_cb>, but only processes up to C<$max_requests> requests |
936 | =item IO::AIO::max_poll_time $seconds |
798 | at a time. |
|
|
799 | |
937 | |
800 | Useful if you want to ensure some level of interactiveness when perl is |
938 | These set the maximum number of requests (default C<0>, meaning infinity) |
801 | not fast enough to process all requests in time. |
939 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
940 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
941 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
942 | of time C<poll_cb> is allowed to use). |
|
|
943 | |
|
|
944 | Setting these is useful if you want to ensure some level of |
|
|
945 | interactiveness when perl is not fast enough to process all requests in |
|
|
946 | time. |
|
|
947 | |
|
|
948 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
802 | |
949 | |
803 | Example: Install an Event watcher that automatically calls |
950 | Example: Install an Event watcher that automatically calls |
804 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
951 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
805 | program get the CPU sometimes even under high AIO load. |
952 | program get the CPU sometimes even under high AIO load. |
806 | |
953 | |
|
|
954 | # try not to spend much more than 0.1s in poll_cb |
|
|
955 | IO::AIO::max_poll_time 0.1; |
|
|
956 | |
|
|
957 | # use a low priority so other tasks have priority |
807 | Event->io (fd => IO::AIO::poll_fileno, |
958 | Event->io (fd => IO::AIO::poll_fileno, |
808 | poll => 'r', nice => 1, |
959 | poll => 'r', nice => 1, |
809 | cb => sub { IO::AIO::poll_some 256 }); |
960 | cb => &IO::AIO::poll_cb); |
810 | |
961 | |
811 | =item IO::AIO::poll_wait |
962 | =item IO::AIO::poll_wait |
812 | |
963 | |
813 | Wait till the result filehandle becomes ready for reading (simply does a |
964 | Wait till the result filehandle becomes ready for reading (simply does a |
814 | C<select> on the filehandle. This is useful if you want to synchronously wait |
965 | C<select> on the filehandle. This is useful if you want to synchronously |
815 | for some requests to finish). |
966 | wait for some requests to finish). |
816 | |
967 | |
817 | See C<nreqs> for an example. |
968 | See C<nreqs> for an example. |
818 | |
969 | |
|
|
970 | =item IO::AIO::poll |
|
|
971 | |
|
|
972 | Waits until some requests have been handled. |
|
|
973 | |
|
|
974 | Strictly equivalent to: |
|
|
975 | |
|
|
976 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
977 | if IO::AIO::nreqs; |
|
|
978 | |
819 | =item IO::AIO::nreqs |
979 | =item IO::AIO::flush |
820 | |
980 | |
821 | Returns the number of requests currently outstanding (i.e. for which their |
981 | Wait till all outstanding AIO requests have been handled. |
822 | callback has not been invoked yet). |
|
|
823 | |
982 | |
824 | Example: wait till there are no outstanding requests anymore: |
983 | Strictly equivalent to: |
825 | |
984 | |
826 | IO::AIO::poll_wait, IO::AIO::poll_cb |
985 | IO::AIO::poll_wait, IO::AIO::poll_cb |
827 | while IO::AIO::nreqs; |
986 | while IO::AIO::nreqs; |
828 | |
987 | |
829 | =item IO::AIO::flush |
988 | =head3 CONTROLLING THE NUMBER OF THREADS |
830 | |
|
|
831 | Wait till all outstanding AIO requests have been handled. |
|
|
832 | |
|
|
833 | Strictly equivalent to: |
|
|
834 | |
|
|
835 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
836 | while IO::AIO::nreqs; |
|
|
837 | |
|
|
838 | =item IO::AIO::poll |
|
|
839 | |
|
|
840 | Waits until some requests have been handled. |
|
|
841 | |
|
|
842 | Strictly equivalent to: |
|
|
843 | |
|
|
844 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
845 | if IO::AIO::nreqs; |
|
|
846 | |
989 | |
847 | =item IO::AIO::min_parallel $nthreads |
990 | =item IO::AIO::min_parallel $nthreads |
848 | |
991 | |
849 | Set the minimum number of AIO threads to C<$nthreads>. The current |
992 | Set the minimum number of AIO threads to C<$nthreads>. The current |
850 | default is C<8>, which means eight asynchronous operations can execute |
993 | default is C<8>, which means eight asynchronous operations can execute |
851 | concurrently at any one time (the number of outstanding requests, |
994 | concurrently at any one time (the number of outstanding requests, |
852 | however, is unlimited). |
995 | however, is unlimited). |
853 | |
996 | |
854 | IO::AIO starts threads only on demand, when an AIO request is queued and |
997 | IO::AIO starts threads only on demand, when an AIO request is queued and |
855 | no free thread exists. |
998 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
999 | create demand for a hundred threads, even if it turns out that everything |
|
|
1000 | is in the cache and could have been processed faster by a single thread. |
856 | |
1001 | |
857 | It is recommended to keep the number of threads relatively low, as some |
1002 | It is recommended to keep the number of threads relatively low, as some |
858 | Linux kernel versions will scale negatively with the number of threads |
1003 | Linux kernel versions will scale negatively with the number of threads |
859 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
1004 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
860 | versions, 4-32 threads should be fine. |
1005 | versions, 4-32 threads should be fine. |
… | |
… | |
874 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1019 | This module automatically runs C<max_parallel 0> at program end, to ensure |
875 | that all threads are killed and that there are no outstanding requests. |
1020 | that all threads are killed and that there are no outstanding requests. |
876 | |
1021 | |
877 | Under normal circumstances you don't need to call this function. |
1022 | Under normal circumstances you don't need to call this function. |
878 | |
1023 | |
|
|
1024 | =item IO::AIO::max_idle $nthreads |
|
|
1025 | |
|
|
1026 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
|
|
1027 | threads that did not get a request to process within 10 seconds). That |
|
|
1028 | means if a thread becomes idle while C<$nthreads> other threads are also |
|
|
1029 | idle, it will free its resources and exit. |
|
|
1030 | |
|
|
1031 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1032 | to allow for extremely high load situations, but want to free resources |
|
|
1033 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1034 | |
|
|
1035 | The default is probably ok in most situations, especially if thread |
|
|
1036 | creation is fast. If thread creation is very slow on your system you might |
|
|
1037 | want to use larger values. |
|
|
1038 | |
879 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
1039 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
880 | |
1040 | |
881 | This is a very bad function to use in interactive programs because it |
1041 | This is a very bad function to use in interactive programs because it |
882 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
1042 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
883 | use an C<aio_group> together with a feed callback. |
1043 | use an C<aio_group> together with a feed callback. |
… | |
… | |
892 | |
1052 | |
893 | You can still queue as many requests as you want. Therefore, |
1053 | You can still queue as many requests as you want. Therefore, |
894 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
1054 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
895 | as a stop gap to shield against fatal memory overflow (with large values). |
1055 | as a stop gap to shield against fatal memory overflow (with large values). |
896 | |
1056 | |
|
|
1057 | =head3 STATISTICAL INFORMATION |
|
|
1058 | |
|
|
1059 | =item IO::AIO::nreqs |
|
|
1060 | |
|
|
1061 | Returns the number of requests currently in the ready, execute or pending |
|
|
1062 | states (i.e. for which their callback has not been invoked yet). |
|
|
1063 | |
|
|
1064 | Example: wait till there are no outstanding requests anymore: |
|
|
1065 | |
|
|
1066 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1067 | while IO::AIO::nreqs; |
|
|
1068 | |
|
|
1069 | =item IO::AIO::nready |
|
|
1070 | |
|
|
1071 | Returns the number of requests currently in the ready state (not yet |
|
|
1072 | executed). |
|
|
1073 | |
|
|
1074 | =item IO::AIO::npending |
|
|
1075 | |
|
|
1076 | Returns the number of requests currently in the pending state (executed, |
|
|
1077 | but not yet processed by poll_cb). |
|
|
1078 | |
897 | =back |
1079 | =back |
898 | |
1080 | |
899 | =cut |
1081 | =cut |
900 | |
1082 | |
901 | # support function to convert a fd into a perl filehandle |
1083 | # support function to convert a fd into a perl filehandle |
… | |
… | |
915 | } |
1097 | } |
916 | |
1098 | |
917 | min_parallel 8; |
1099 | min_parallel 8; |
918 | |
1100 | |
919 | END { |
1101 | END { |
920 | max_parallel 0; |
1102 | min_parallel 1; |
921 | } |
1103 | flush; |
|
|
1104 | }; |
922 | |
1105 | |
923 | 1; |
1106 | 1; |
924 | |
1107 | |
925 | =head2 FORK BEHAVIOUR |
1108 | =head2 FORK BEHAVIOUR |
926 | |
1109 | |