… | |
… | |
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", 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 | |
… | |
… | |
50 | |
51 | |
51 | =head1 DESCRIPTION |
52 | =head1 DESCRIPTION |
52 | |
53 | |
53 | This module implements asynchronous I/O using whatever means your |
54 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. |
55 | operating system supports. |
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56 | |
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57 | Asynchronous means that operations that can normally block your program |
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58 | (e.g. reading from disk) will be done asynchronously: the operation |
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59 | will still block, but you can do something else in the meantime. This |
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60 | is extremely useful for programs that need to stay interactive even |
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61 | when doing heavy I/O (GUI programs, high performance network servers |
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62 | etc.), but can also be used to easily do operations in parallel that are |
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63 | normally done sequentially, e.g. stat'ing many files, which is much faster |
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64 | on a RAID volume or over NFS when you do a number of stat operations |
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65 | concurrently. |
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66 | |
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67 | While most of this works on all types of file descriptors (for example |
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68 | sockets), using these functions on file descriptors that support |
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69 | nonblocking operation (again, sockets, pipes etc.) is very inefficient or |
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70 | might not work (aio_read fails on sockets/pipes/fifos). Use an event loop |
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71 | for that (such as the L<Event|Event> module): IO::AIO will naturally fit |
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72 | into such an event loop itself. |
55 | |
73 | |
56 | In this version, a number of threads are started that execute your |
74 | In this version, a number of threads are started that execute your |
57 | requests and signal their completion. You don't need thread support |
75 | 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 |
76 | 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 |
77 | 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 |
78 | functions available on many operating systems. However, they are often |
61 | not well-supported or restricted (Linux doesn't allow them on normal |
79 | 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 |
80 | files currently, for example), and they would only support aio_read and |
63 | aio_write, so the remaining functionality would have to be implemented |
81 | aio_write, so the remaining functionality would have to be implemented |
64 | using threads anyway. |
82 | using threads anyway. |
65 | |
83 | |
66 | Although the module will work with in the presence of other (Perl-) |
84 | 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 |
85 | 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 |
86 | 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. |
87 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
70 | |
88 | |
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89 | =head2 EXAMPLE |
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90 | |
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91 | This is a simple example that uses the Event module and loads |
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92 | F</etc/passwd> asynchronously: |
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93 | |
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94 | use Fcntl; |
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95 | use Event; |
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96 | use IO::AIO; |
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97 | |
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98 | # register the IO::AIO callback with Event |
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99 | Event->io (fd => IO::AIO::poll_fileno, |
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100 | poll => 'r', |
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101 | cb => \&IO::AIO::poll_cb); |
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102 | |
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103 | # queue the request to open /etc/passwd |
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104 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
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105 | my $fh = shift |
|
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106 | or die "error while opening: $!"; |
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107 | |
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108 | # stat'ing filehandles is generally non-blocking |
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109 | my $size = -s $fh; |
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110 | |
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111 | # queue a request to read the file |
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112 | my $contents; |
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113 | aio_read $fh, 0, $size, $contents, 0, sub { |
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114 | $_[0] == $size |
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115 | or die "short read: $!"; |
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116 | |
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117 | close $fh; |
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118 | |
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119 | # file contents now in $contents |
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120 | print $contents; |
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121 | |
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122 | # exit event loop and program |
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123 | Event::unloop; |
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124 | }; |
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125 | }; |
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126 | |
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127 | # possibly queue up other requests, or open GUI windows, |
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128 | # check for sockets etc. etc. |
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129 | |
|
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130 | # process events as long as there are some: |
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131 | Event::loop; |
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132 | |
71 | =head1 REQUEST ANATOMY AND LIFETIME |
133 | =head1 REQUEST ANATOMY AND LIFETIME |
72 | |
134 | |
73 | Every C<aio_*> function creates a request. which is a C data structure not |
135 | Every C<aio_*> function creates a request. which is a C data structure not |
74 | directly visible to Perl. |
136 | directly visible to Perl. |
75 | |
137 | |
… | |
… | |
116 | Request has reached the end of its lifetime and holds no resources anymore |
178 | 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 |
179 | (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 |
180 | aio request is severed and calling its methods will either do nothing or |
119 | result in a runtime error). |
181 | result in a runtime error). |
120 | |
182 | |
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183 | =back |
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184 | |
121 | =cut |
185 | =cut |
122 | |
186 | |
123 | package IO::AIO; |
187 | package IO::AIO; |
124 | |
188 | |
125 | no warnings; |
189 | no warnings; |
126 | use strict 'vars'; |
190 | use strict 'vars'; |
127 | |
191 | |
128 | use base 'Exporter'; |
192 | use base 'Exporter'; |
129 | |
193 | |
130 | BEGIN { |
194 | BEGIN { |
131 | our $VERSION = '2.0'; |
195 | our $VERSION = '2.2'; |
132 | |
196 | |
133 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
197 | 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 |
198 | 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 |
199 | aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link |
136 | aio_group aio_nop); |
200 | aio_move aio_copy aio_group aio_nop aio_mknod); |
137 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
201 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
138 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
202 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
139 | min_parallel max_parallel max_outstanding nreqs); |
203 | min_parallel max_parallel max_idle |
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204 | nreqs nready npending nthreads |
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205 | max_poll_time max_poll_reqs); |
140 | |
206 | |
141 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
207 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
142 | |
208 | |
143 | require XSLoader; |
209 | require XSLoader; |
144 | XSLoader::load ("IO::AIO", $VERSION); |
210 | XSLoader::load ("IO::AIO", $VERSION); |
145 | } |
211 | } |
146 | |
212 | |
147 | =head1 FUNCTIONS |
213 | =head1 FUNCTIONS |
148 | |
214 | |
149 | =head2 AIO FUNCTIONS |
215 | =head2 AIO REQUEST FUNCTIONS |
150 | |
216 | |
151 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
217 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
152 | with the same name (sans C<aio_>). The arguments are similar or identical, |
218 | with the same name (sans C<aio_>). The arguments are similar or identical, |
153 | and they all accept an additional (and optional) C<$callback> argument |
219 | 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 |
220 | which must be a code reference. This code reference will get called with |
… | |
… | |
157 | syscall has been executed asynchronously. |
223 | syscall has been executed asynchronously. |
158 | |
224 | |
159 | All functions expecting a filehandle keep a copy of the filehandle |
225 | All functions expecting a filehandle keep a copy of the filehandle |
160 | internally until the request has finished. |
226 | internally until the request has finished. |
161 | |
227 | |
162 | All requests return objects of type L<IO::AIO::REQ> that allow further |
228 | All functions return request objects of type L<IO::AIO::REQ> that allow |
163 | manipulation of those requests while they are in-flight. |
229 | further manipulation of those requests while they are in-flight. |
164 | |
230 | |
165 | The pathnames you pass to these routines I<must> be absolute and |
231 | 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 |
232 | 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 |
233 | request is being executed, the current working directory could have |
168 | changed. Alternatively, you can make sure that you never change the |
234 | changed. Alternatively, you can make sure that you never change the |
169 | current working directory. |
235 | current working directory anywhere in the program and then use relative |
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236 | paths. |
170 | |
237 | |
171 | To encode pathnames to byte form, either make sure you either: a) |
238 | 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 |
239 | 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 |
240 | 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 |
241 | 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) |
242 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
176 | use something else. |
243 | use something else to ensure your scalar has the correct contents. |
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244 | |
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245 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
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246 | handles correctly wether it is set or not. |
177 | |
247 | |
178 | =over 4 |
248 | =over 4 |
179 | |
249 | |
180 | =item aioreq_pri $pri |
250 | =item $prev_pri = aioreq_pri [$pri] |
181 | |
251 | |
182 | Sets the priority for the next aio request. The default priority |
252 | Returns the priority value that would be used for the next request and, if |
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253 | C<$pri> is given, sets the priority for the next aio request. |
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254 | |
183 | is C<0>, the minimum and maximum priorities are C<-4> and C<4>, |
255 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
184 | respectively. Requests with higher priority will be serviced first. |
256 | and C<4>, respectively. Requests with higher priority will be serviced |
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257 | first. |
185 | |
258 | |
186 | The priority will be reset to C<0> after each call to one of the C<aio_> |
259 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
187 | functions. |
260 | functions. |
188 | |
261 | |
189 | Example: open a file with low priority, then read something from it with |
262 | 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 |
263 | higher priority so the read request is serviced before other low priority |
191 | open requests (potentially spamming the cache): |
264 | open requests (potentially spamming the cache): |
… | |
… | |
201 | }; |
274 | }; |
202 | |
275 | |
203 | =item aioreq_nice $pri_adjust |
276 | =item aioreq_nice $pri_adjust |
204 | |
277 | |
205 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
278 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
206 | priority, so effects are cumulative. |
279 | priority, so the effect is cumulative. |
207 | |
280 | |
208 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
281 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
209 | |
282 | |
210 | Asynchronously open or create a file and call the callback with a newly |
283 | Asynchronously open or create a file and call the callback with a newly |
211 | created filehandle for the file. |
284 | created filehandle for the file. |
… | |
… | |
261 | |
334 | |
262 | aio_read $fh, 7, 15, $buffer, 0, sub { |
335 | aio_read $fh, 7, 15, $buffer, 0, sub { |
263 | $_[0] > 0 or die "read error: $!"; |
336 | $_[0] > 0 or die "read error: $!"; |
264 | print "read $_[0] bytes: <$buffer>\n"; |
337 | print "read $_[0] bytes: <$buffer>\n"; |
265 | }; |
338 | }; |
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 | }; |
|
|
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 | } |
|
|
317 | }; |
|
|
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 | |
|
|
323 | } else { |
|
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324 | $grp->result (-1); |
|
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325 | } |
|
|
326 | }; |
|
|
327 | } else { |
|
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328 | $grp->result ($_[0]); |
|
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329 | } |
|
|
330 | }; |
|
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331 | |
|
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332 | $grp |
|
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333 | } |
|
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334 | |
339 | |
335 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
340 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
336 | |
341 | |
337 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
342 | 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 |
343 | reading at byte offset C<$in_offset>, and starts writing at the current |
… | |
… | |
394 | =item aio_unlink $pathname, $callback->($status) |
399 | =item aio_unlink $pathname, $callback->($status) |
395 | |
400 | |
396 | Asynchronously unlink (delete) a file and call the callback with the |
401 | Asynchronously unlink (delete) a file and call the callback with the |
397 | result code. |
402 | result code. |
398 | |
403 | |
|
|
404 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
|
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405 | |
|
|
406 | [EXPERIMENTAL] |
|
|
407 | |
|
|
408 | Asynchronously create a device node (or fifo). See mknod(2). |
|
|
409 | |
|
|
410 | The only (POSIX-) portable way of calling this function is: |
|
|
411 | |
|
|
412 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
413 | |
399 | =item aio_link $srcpath, $dstpath, $callback->($status) |
414 | =item aio_link $srcpath, $dstpath, $callback->($status) |
400 | |
415 | |
401 | Asynchronously create a new link to the existing object at C<$srcpath> at |
416 | 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. |
417 | the path C<$dstpath> and call the callback with the result code. |
403 | |
418 | |
404 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
419 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
405 | |
420 | |
406 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
421 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
407 | the path C<$dstpath> and call the callback with the result code. |
422 | the path C<$dstpath> and call the callback with the result code. |
|
|
423 | |
|
|
424 | =item aio_readlink $path, $callback->($link) |
|
|
425 | |
|
|
426 | Asynchronously read the symlink specified by C<$path> and pass it to |
|
|
427 | the callback. If an error occurs, nothing or undef gets passed to the |
|
|
428 | callback. |
408 | |
429 | |
409 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
430 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
410 | |
431 | |
411 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
432 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
412 | rename(2) and call the callback with the result code. |
433 | rename(2) and call the callback with the result code. |
… | |
… | |
423 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
444 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
424 | |
445 | |
425 | The callback a single argument which is either C<undef> or an array-ref |
446 | The callback a single argument which is either C<undef> or an array-ref |
426 | with the filenames. |
447 | with the filenames. |
427 | |
448 | |
|
|
449 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
450 | |
|
|
451 | Try to copy the I<file> (directories not supported as either source or |
|
|
452 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
453 | the C<0> (error) or C<-1> ok. |
|
|
454 | |
|
|
455 | This is a composite request that it creates the destination file with |
|
|
456 | mode 0200 and copies the contents of the source file into it using |
|
|
457 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
|
|
458 | uid/gid, in that order. |
|
|
459 | |
|
|
460 | If an error occurs, the partial destination file will be unlinked, if |
|
|
461 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
462 | errors are being ignored. |
|
|
463 | |
|
|
464 | =cut |
|
|
465 | |
|
|
466 | sub aio_copy($$;$) { |
|
|
467 | my ($src, $dst, $cb) = @_; |
|
|
468 | |
|
|
469 | my $pri = aioreq_pri; |
|
|
470 | my $grp = aio_group $cb; |
|
|
471 | |
|
|
472 | aioreq_pri $pri; |
|
|
473 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
474 | if (my $src_fh = $_[0]) { |
|
|
475 | my @stat = stat $src_fh; |
|
|
476 | |
|
|
477 | aioreq_pri $pri; |
|
|
478 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
479 | if (my $dst_fh = $_[0]) { |
|
|
480 | aioreq_pri $pri; |
|
|
481 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
482 | if ($_[0] == $stat[7]) { |
|
|
483 | $grp->result (0); |
|
|
484 | close $src_fh; |
|
|
485 | |
|
|
486 | # those should not normally block. should. should. |
|
|
487 | utime $stat[8], $stat[9], $dst; |
|
|
488 | chmod $stat[2] & 07777, $dst_fh; |
|
|
489 | chown $stat[4], $stat[5], $dst_fh; |
|
|
490 | close $dst_fh; |
|
|
491 | } else { |
|
|
492 | $grp->result (-1); |
|
|
493 | close $src_fh; |
|
|
494 | close $dst_fh; |
|
|
495 | |
|
|
496 | aioreq $pri; |
|
|
497 | add $grp aio_unlink $dst; |
|
|
498 | } |
|
|
499 | }; |
|
|
500 | } else { |
|
|
501 | $grp->result (-1); |
|
|
502 | } |
|
|
503 | }, |
|
|
504 | |
|
|
505 | } else { |
|
|
506 | $grp->result (-1); |
|
|
507 | } |
|
|
508 | }; |
|
|
509 | |
|
|
510 | $grp |
|
|
511 | } |
|
|
512 | |
|
|
513 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
514 | |
|
|
515 | Try to move the I<file> (directories not supported as either source or |
|
|
516 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
517 | the C<0> (error) or C<-1> ok. |
|
|
518 | |
|
|
519 | This is a composite request that tries to rename(2) the file first. If |
|
|
520 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
521 | that is successful, unlinking the C<$srcpath>. |
|
|
522 | |
|
|
523 | =cut |
|
|
524 | |
|
|
525 | sub aio_move($$;$) { |
|
|
526 | my ($src, $dst, $cb) = @_; |
|
|
527 | |
|
|
528 | my $pri = aioreq_pri; |
|
|
529 | my $grp = aio_group $cb; |
|
|
530 | |
|
|
531 | aioreq_pri $pri; |
|
|
532 | add $grp aio_rename $src, $dst, sub { |
|
|
533 | if ($_[0] && $! == EXDEV) { |
|
|
534 | aioreq_pri $pri; |
|
|
535 | add $grp aio_copy $src, $dst, sub { |
|
|
536 | $grp->result ($_[0]); |
|
|
537 | |
|
|
538 | if (!$_[0]) { |
|
|
539 | aioreq_pri $pri; |
|
|
540 | add $grp aio_unlink $src; |
|
|
541 | } |
|
|
542 | }; |
|
|
543 | } else { |
|
|
544 | $grp->result ($_[0]); |
|
|
545 | } |
|
|
546 | }; |
|
|
547 | |
|
|
548 | $grp |
|
|
549 | } |
|
|
550 | |
428 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
551 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
429 | |
552 | |
430 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
553 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
431 | separate the entries of directory C<$path> into two sets of names, ones |
554 | efficiently separate the entries of directory C<$path> into two sets of |
432 | you can recurse into (directories or links to them), and ones you cannot |
555 | names, directories you can recurse into (directories), and ones you cannot |
433 | recurse into (everything else). |
556 | recurse into (everything else, including symlinks to directories). |
434 | |
557 | |
435 | C<aio_scandir> is a composite request that creates of many sub requests_ |
558 | 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 |
559 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
437 | this function generates. If it is C<< <= 0 >>, then a suitable default |
560 | this function generates. If it is C<< <= 0 >>, then a suitable default |
438 | will be chosen (currently 6). |
561 | will be chosen (currently 4). |
439 | |
562 | |
440 | On error, the callback is called without arguments, otherwise it receives |
563 | On error, the callback is called without arguments, otherwise it receives |
441 | two array-refs with path-relative entry names. |
564 | two array-refs with path-relative entry names. |
442 | |
565 | |
443 | Example: |
566 | Example: |
… | |
… | |
480 | =cut |
603 | =cut |
481 | |
604 | |
482 | sub aio_scandir($$$) { |
605 | sub aio_scandir($$$) { |
483 | my ($path, $maxreq, $cb) = @_; |
606 | my ($path, $maxreq, $cb) = @_; |
484 | |
607 | |
|
|
608 | my $pri = aioreq_pri; |
|
|
609 | |
485 | my $grp = aio_group $cb; |
610 | my $grp = aio_group $cb; |
486 | |
611 | |
487 | $maxreq = 6 if $maxreq <= 0; |
612 | $maxreq = 4 if $maxreq <= 0; |
488 | |
613 | |
489 | # stat once |
614 | # stat once |
|
|
615 | aioreq_pri $pri; |
490 | add $grp aio_stat $path, sub { |
616 | add $grp aio_stat $path, sub { |
491 | return $grp->result () if $_[0]; |
617 | return $grp->result () if $_[0]; |
492 | my $now = time; |
618 | my $now = time; |
493 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
619 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
494 | |
620 | |
495 | # read the directory entries |
621 | # read the directory entries |
|
|
622 | aioreq_pri $pri; |
496 | add $grp aio_readdir $path, sub { |
623 | add $grp aio_readdir $path, sub { |
497 | my $entries = shift |
624 | my $entries = shift |
498 | or return $grp->result (); |
625 | or return $grp->result (); |
499 | |
626 | |
500 | # stat the dir another time |
627 | # stat the dir another time |
|
|
628 | aioreq_pri $pri; |
501 | add $grp aio_stat $path, sub { |
629 | add $grp aio_stat $path, sub { |
502 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
630 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
503 | |
631 | |
504 | my $ndirs; |
632 | my $ndirs; |
505 | |
633 | |
… | |
… | |
529 | limit $statgrp $maxreq; |
657 | limit $statgrp $maxreq; |
530 | feed $statgrp sub { |
658 | feed $statgrp sub { |
531 | return unless @$entries; |
659 | return unless @$entries; |
532 | my $entry = pop @$entries; |
660 | my $entry = pop @$entries; |
533 | |
661 | |
|
|
662 | aioreq_pri $pri; |
534 | add $statgrp aio_stat "$path/$entry/.", sub { |
663 | add $statgrp aio_stat "$path/$entry/.", sub { |
535 | if ($_[0] < 0) { |
664 | if ($_[0] < 0) { |
536 | push @nondirs, $entry; |
665 | push @nondirs, $entry; |
537 | } else { |
666 | } else { |
538 | # need to check for real directory |
667 | # need to check for real directory |
|
|
668 | aioreq_pri $pri; |
539 | add $statgrp aio_lstat "$path/$entry", sub { |
669 | add $statgrp aio_lstat "$path/$entry", sub { |
540 | if (-d _) { |
670 | if (-d _) { |
541 | push @dirs, $entry; |
671 | push @dirs, $entry; |
542 | |
672 | |
543 | unless (--$ndirs) { |
673 | unless (--$ndirs) { |
… | |
… | |
682 | =item * They can also can also be added to other IO::AIO::GRP objects. |
812 | =item * They can also can also be added to other IO::AIO::GRP objects. |
683 | |
813 | |
684 | =item * You must not add requests to a group from within the group callback (or |
814 | =item * You must not add requests to a group from within the group callback (or |
685 | any later time). |
815 | any later time). |
686 | |
816 | |
687 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
688 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
689 | this kind of concurrency-limiting. |
|
|
690 | |
|
|
691 | =back |
817 | =back |
692 | |
818 | |
693 | Their lifetime, simplified, looks like this: when they are empty, they |
819 | Their lifetime, simplified, looks like this: when they are empty, they |
694 | will finish very quickly. If they contain only requests that are in the |
820 | will finish very quickly. If they contain only requests that are in the |
695 | C<done> state, they will also finish. Otherwise they will continue to |
821 | C<done> state, they will also finish. Otherwise they will continue to |
… | |
… | |
718 | itself. Useful when you queued a lot of events but got a result early. |
844 | itself. Useful when you queued a lot of events but got a result early. |
719 | |
845 | |
720 | =item $grp->result (...) |
846 | =item $grp->result (...) |
721 | |
847 | |
722 | Set the result value(s) that will be passed to the group callback when all |
848 | Set the result value(s) that will be passed to the group callback when all |
723 | subrequests have finished. By default, no argument will be passed. |
849 | subrequests have finished and set thre groups errno to the current value |
|
|
850 | of errno (just like calling C<errno> without an error number). By default, |
|
|
851 | no argument will be passed and errno is zero. |
|
|
852 | |
|
|
853 | =item $grp->errno ([$errno]) |
|
|
854 | |
|
|
855 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
856 | when the argument is missing. |
|
|
857 | |
|
|
858 | Every aio request has an associated errno value that is restored when |
|
|
859 | the callback is invoked. This method lets you change this value from its |
|
|
860 | default (0). |
|
|
861 | |
|
|
862 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
863 | before the call to C<result>, or call c<errno> after it. |
724 | |
864 | |
725 | =item feed $grp $callback->($grp) |
865 | =item feed $grp $callback->($grp) |
726 | |
866 | |
727 | Sets a feeder/generator on this group: every group can have an attached |
867 | Sets a feeder/generator on this group: every group can have an attached |
728 | generator that generates requests if idle. The idea behind this is that, |
868 | generator that generates requests if idle. The idea behind this is that, |
… | |
… | |
767 | |
907 | |
768 | =back |
908 | =back |
769 | |
909 | |
770 | =head2 SUPPORT FUNCTIONS |
910 | =head2 SUPPORT FUNCTIONS |
771 | |
911 | |
|
|
912 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
913 | |
772 | =over 4 |
914 | =over 4 |
773 | |
915 | |
774 | =item $fileno = IO::AIO::poll_fileno |
916 | =item $fileno = IO::AIO::poll_fileno |
775 | |
917 | |
776 | Return the I<request result pipe file descriptor>. This filehandle must be |
918 | Return the I<request result pipe file descriptor>. This filehandle must be |
… | |
… | |
780 | |
922 | |
781 | See C<poll_cb> for an example. |
923 | See C<poll_cb> for an example. |
782 | |
924 | |
783 | =item IO::AIO::poll_cb |
925 | =item IO::AIO::poll_cb |
784 | |
926 | |
785 | Process all outstanding events on the result pipe. You have to call this |
927 | Process some outstanding events on the result pipe. You have to call this |
786 | regularly. Returns the number of events processed. Returns immediately |
928 | regularly. Returns the number of events processed. Returns immediately |
787 | when no events are outstanding. |
929 | when no events are outstanding. The amount of events processed depends on |
|
|
930 | the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. |
|
|
931 | |
|
|
932 | If not all requests were processed for whatever reason, the filehandle |
|
|
933 | will still be ready when C<poll_cb> returns. |
788 | |
934 | |
789 | Example: Install an Event watcher that automatically calls |
935 | Example: Install an Event watcher that automatically calls |
790 | IO::AIO::poll_cb with high priority: |
936 | IO::AIO::poll_cb with high priority: |
791 | |
937 | |
792 | Event->io (fd => IO::AIO::poll_fileno, |
938 | Event->io (fd => IO::AIO::poll_fileno, |
793 | poll => 'r', async => 1, |
939 | poll => 'r', async => 1, |
794 | cb => \&IO::AIO::poll_cb); |
940 | cb => \&IO::AIO::poll_cb); |
795 | |
941 | |
|
|
942 | =item IO::AIO::max_poll_reqs $nreqs |
|
|
943 | |
|
|
944 | =item IO::AIO::max_poll_time $seconds |
|
|
945 | |
|
|
946 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
947 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
948 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
949 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
950 | of time C<poll_cb> is allowed to use). |
|
|
951 | |
|
|
952 | Setting C<max_poll_time> to a non-zero value creates an overhead of one |
|
|
953 | syscall per request processed, which is not normally a problem unless your |
|
|
954 | callbacks are really really fast or your OS is really really slow (I am |
|
|
955 | not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead. |
|
|
956 | |
|
|
957 | Setting these is useful if you want to ensure some level of |
|
|
958 | interactiveness when perl is not fast enough to process all requests in |
|
|
959 | time. |
|
|
960 | |
|
|
961 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
|
|
962 | |
|
|
963 | Example: Install an Event watcher that automatically calls |
|
|
964 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
|
|
965 | program get the CPU sometimes even under high AIO load. |
|
|
966 | |
|
|
967 | # try not to spend much more than 0.1s in poll_cb |
|
|
968 | IO::AIO::max_poll_time 0.1; |
|
|
969 | |
|
|
970 | # use a low priority so other tasks have priority |
|
|
971 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
972 | poll => 'r', nice => 1, |
|
|
973 | cb => &IO::AIO::poll_cb); |
|
|
974 | |
796 | =item IO::AIO::poll_wait |
975 | =item IO::AIO::poll_wait |
797 | |
976 | |
|
|
977 | If there are any outstanding requests and none of them in the result |
798 | Wait till the result filehandle becomes ready for reading (simply does a |
978 | phase, wait till the result filehandle becomes ready for reading (simply |
799 | C<select> on the filehandle. This is useful if you want to synchronously wait |
979 | does a C<select> on the filehandle. This is useful if you want to |
800 | for some requests to finish). |
980 | synchronously wait for some requests to finish). |
801 | |
981 | |
802 | See C<nreqs> for an example. |
982 | See C<nreqs> for an example. |
803 | |
983 | |
|
|
984 | =item IO::AIO::poll |
|
|
985 | |
|
|
986 | Waits until some requests have been handled. |
|
|
987 | |
|
|
988 | Returns the number of requests processed, but is otherwise strictly |
|
|
989 | equivalent to: |
|
|
990 | |
|
|
991 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
992 | |
804 | =item IO::AIO::nreqs |
993 | =item IO::AIO::flush |
805 | |
994 | |
806 | Returns the number of requests currently outstanding (i.e. for which their |
995 | Wait till all outstanding AIO requests have been handled. |
807 | callback has not been invoked yet). |
|
|
808 | |
996 | |
809 | Example: wait till there are no outstanding requests anymore: |
997 | Strictly equivalent to: |
810 | |
998 | |
811 | IO::AIO::poll_wait, IO::AIO::poll_cb |
999 | IO::AIO::poll_wait, IO::AIO::poll_cb |
812 | while IO::AIO::nreqs; |
1000 | while IO::AIO::nreqs; |
813 | |
1001 | |
814 | =item IO::AIO::flush |
1002 | =head3 CONTROLLING THE NUMBER OF THREADS |
815 | |
|
|
816 | Wait till all outstanding AIO requests have been handled. |
|
|
817 | |
|
|
818 | Strictly equivalent to: |
|
|
819 | |
|
|
820 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
821 | while IO::AIO::nreqs; |
|
|
822 | |
|
|
823 | =item IO::AIO::poll |
|
|
824 | |
|
|
825 | Waits until some requests have been handled. |
|
|
826 | |
|
|
827 | Strictly equivalent to: |
|
|
828 | |
|
|
829 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
830 | if IO::AIO::nreqs; |
|
|
831 | |
1003 | |
832 | =item IO::AIO::min_parallel $nthreads |
1004 | =item IO::AIO::min_parallel $nthreads |
833 | |
1005 | |
834 | Set the minimum number of AIO threads to C<$nthreads>. The current |
1006 | Set the minimum number of AIO threads to C<$nthreads>. The current |
835 | default is C<8>, which means eight asynchronous operations can execute |
1007 | default is C<8>, which means eight asynchronous operations can execute |
836 | concurrently at any one time (the number of outstanding requests, |
1008 | concurrently at any one time (the number of outstanding requests, |
837 | however, is unlimited). |
1009 | however, is unlimited). |
838 | |
1010 | |
839 | IO::AIO starts threads only on demand, when an AIO request is queued and |
1011 | IO::AIO starts threads only on demand, when an AIO request is queued and |
840 | no free thread exists. |
1012 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
1013 | create demand for a hundred threads, even if it turns out that everything |
|
|
1014 | is in the cache and could have been processed faster by a single thread. |
841 | |
1015 | |
842 | It is recommended to keep the number of threads relatively low, as some |
1016 | It is recommended to keep the number of threads relatively low, as some |
843 | Linux kernel versions will scale negatively with the number of threads |
1017 | Linux kernel versions will scale negatively with the number of threads |
844 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
1018 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
845 | versions, 4-32 threads should be fine. |
1019 | versions, 4-32 threads should be fine. |
… | |
… | |
859 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1033 | This module automatically runs C<max_parallel 0> at program end, to ensure |
860 | that all threads are killed and that there are no outstanding requests. |
1034 | that all threads are killed and that there are no outstanding requests. |
861 | |
1035 | |
862 | Under normal circumstances you don't need to call this function. |
1036 | Under normal circumstances you don't need to call this function. |
863 | |
1037 | |
|
|
1038 | =item IO::AIO::max_idle $nthreads |
|
|
1039 | |
|
|
1040 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
|
|
1041 | threads that did not get a request to process within 10 seconds). That |
|
|
1042 | means if a thread becomes idle while C<$nthreads> other threads are also |
|
|
1043 | idle, it will free its resources and exit. |
|
|
1044 | |
|
|
1045 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1046 | to allow for extremely high load situations, but want to free resources |
|
|
1047 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1048 | |
|
|
1049 | The default is probably ok in most situations, especially if thread |
|
|
1050 | creation is fast. If thread creation is very slow on your system you might |
|
|
1051 | want to use larger values. |
|
|
1052 | |
864 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
1053 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
865 | |
1054 | |
866 | [DEPRECATED] |
1055 | This is a very bad function to use in interactive programs because it |
|
|
1056 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1057 | use an C<aio_group> together with a feed callback. |
867 | |
1058 | |
868 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1059 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
869 | try to queue up more than this number of requests, the caller will block until |
1060 | to queue up more than this number of requests, the next call to the |
870 | some requests have been handled. |
1061 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
1062 | function will block until the limit is no longer exceeded. |
871 | |
1063 | |
872 | The default is very large, so normally there is no practical limit. If you |
1064 | The default value is very large, so there is no practical limit on the |
873 | queue up many requests in a loop it often improves speed if you set |
1065 | number of outstanding requests. |
874 | this to a relatively low number, such as C<100>. |
|
|
875 | |
1066 | |
876 | This function does not work well together with C<aio_group>'s, and their |
1067 | You can still queue as many requests as you want. Therefore, |
877 | feeder interface is better suited to limiting concurrency, so do not use |
1068 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
878 | this function. |
1069 | as a stop gap to shield against fatal memory overflow (with large values). |
879 | |
1070 | |
880 | Under normal circumstances you don't need to call this function. |
1071 | =head3 STATISTICAL INFORMATION |
|
|
1072 | |
|
|
1073 | =item IO::AIO::nreqs |
|
|
1074 | |
|
|
1075 | Returns the number of requests currently in the ready, execute or pending |
|
|
1076 | states (i.e. for which their callback has not been invoked yet). |
|
|
1077 | |
|
|
1078 | Example: wait till there are no outstanding requests anymore: |
|
|
1079 | |
|
|
1080 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1081 | while IO::AIO::nreqs; |
|
|
1082 | |
|
|
1083 | =item IO::AIO::nready |
|
|
1084 | |
|
|
1085 | Returns the number of requests currently in the ready state (not yet |
|
|
1086 | executed). |
|
|
1087 | |
|
|
1088 | =item IO::AIO::npending |
|
|
1089 | |
|
|
1090 | Returns the number of requests currently in the pending state (executed, |
|
|
1091 | but not yet processed by poll_cb). |
881 | |
1092 | |
882 | =back |
1093 | =back |
883 | |
1094 | |
884 | =cut |
1095 | =cut |
885 | |
1096 | |
… | |
… | |
900 | } |
1111 | } |
901 | |
1112 | |
902 | min_parallel 8; |
1113 | min_parallel 8; |
903 | |
1114 | |
904 | END { |
1115 | END { |
905 | max_parallel 0; |
1116 | min_parallel 1; |
906 | } |
1117 | flush; |
|
|
1118 | }; |
907 | |
1119 | |
908 | 1; |
1120 | 1; |
909 | |
1121 | |
910 | =head2 FORK BEHAVIOUR |
1122 | =head2 FORK BEHAVIOUR |
911 | |
1123 | |