… | |
… | |
22 | poll => 'r', |
22 | poll => 'r', |
23 | cb => \&IO::AIO::poll_cb); |
23 | cb => \&IO::AIO::poll_cb); |
24 | |
24 | |
25 | # Glib/Gtk2 |
25 | # Glib/Gtk2 |
26 | add_watch Glib::IO IO::AIO::poll_fileno, |
26 | add_watch Glib::IO IO::AIO::poll_fileno, |
27 | in => sub { IO::AIO::poll_cb, 1 }; |
27 | in => sub { IO::AIO::poll_cb; 1 }; |
28 | |
28 | |
29 | # Tk |
29 | # Tk |
30 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
30 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
31 | readable => \&IO::AIO::poll_cb); |
31 | readable => \&IO::AIO::poll_cb); |
32 | |
32 | |
… | |
… | |
48 | not well-supported (Linux doesn't allow them on normal files currently, |
48 | not well-supported (Linux doesn't allow them on normal files currently, |
49 | for example), and they would only support aio_read and aio_write, so the |
49 | for example), and they would only support aio_read and aio_write, so the |
50 | remaining functionality would have to be implemented using threads anyway. |
50 | remaining functionality would have to be implemented using threads anyway. |
51 | |
51 | |
52 | Although the module will work with in the presence of other threads, it is |
52 | Although the module will work with in the presence of other threads, it is |
53 | currently not reentrant, so use appropriate locking yourself. |
53 | currently not reentrant, so use appropriate locking yourself, always call |
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54 | C<poll_cb> from within the same thread, or never call C<poll_cb> (or other |
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55 | C<aio_> functions) recursively. |
54 | |
56 | |
55 | =cut |
57 | =cut |
56 | |
58 | |
57 | package IO::AIO; |
59 | package IO::AIO; |
58 | |
60 | |
|
|
61 | no warnings; |
|
|
62 | |
59 | use base 'Exporter'; |
63 | use base 'Exporter'; |
60 | |
64 | |
61 | use Fcntl (); |
65 | use Fcntl (); |
62 | |
66 | |
63 | BEGIN { |
67 | BEGIN { |
64 | $VERSION = 0.5; |
68 | $VERSION = 1.6; |
65 | |
69 | |
66 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
70 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
67 | aio_fsync aio_fdatasync aio_readahead); |
71 | aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead); |
68 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
72 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
69 | |
73 | |
70 | require XSLoader; |
74 | require XSLoader; |
71 | XSLoader::load IO::AIO, $VERSION; |
75 | XSLoader::load IO::AIO, $VERSION; |
72 | } |
76 | } |
… | |
… | |
81 | which must be a code reference. This code reference will get called with |
85 | which must be a code reference. This code reference will get called with |
82 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
86 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
83 | perl, which usually delivers "false") as it's sole argument when the given |
87 | perl, which usually delivers "false") as it's sole argument when the given |
84 | syscall has been executed asynchronously. |
88 | syscall has been executed asynchronously. |
85 | |
89 | |
86 | All functions that expect a filehandle will also accept a file descriptor. |
90 | All functions expecting a filehandle keep a copy of the filehandle |
|
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91 | internally until the request has finished. |
87 | |
92 | |
88 | The filenames you pass to these routines I<must> be absolute. The reason |
93 | The pathnames you pass to these routines I<must> be absolute and |
89 | for this is that at the time the request is being executed, the current |
94 | encoded in byte form. The reason for the former is that at the time the |
90 | working directory could have changed. Alternatively, you can make sure |
95 | request is being executed, the current working directory could have |
91 | that you never change the current working directory. |
96 | changed. Alternatively, you can make sure that you never change the |
|
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97 | current working directory. |
|
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98 | |
|
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99 | To encode pathnames to byte form, either make sure you either: a) |
|
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100 | always pass in filenames you got from outside (command line, readdir |
|
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101 | etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
|
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102 | your pathnames to the locale (or other) encoding in effect in the user |
|
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103 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
|
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104 | use something else. |
92 | |
105 | |
93 | =over 4 |
106 | =over 4 |
94 | |
107 | |
95 | =item aio_open $pathname, $flags, $mode, $callback |
108 | =item aio_open $pathname, $flags, $mode, $callback |
96 | |
109 | |
… | |
… | |
137 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
150 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
138 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
151 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
139 | callback without the actual number of bytes read (or -1 on error, just |
152 | callback without the actual number of bytes read (or -1 on error, just |
140 | like the syscall). |
153 | like the syscall). |
141 | |
154 | |
|
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155 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
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156 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
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157 | necessary/optional hardware is installed). |
|
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158 | |
142 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
159 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
143 | offset C<0> within the scalar: |
160 | offset C<0> within the scalar: |
144 | |
161 | |
145 | aio_read $fh, 7, 15, $buffer, 0, sub { |
162 | aio_read $fh, 7, 15, $buffer, 0, sub { |
146 | $_[0] > 0 or die "read error: $!"; |
163 | $_[0] > 0 or die "read error: $!"; |
147 | print "read $_[0] bytes: <$buffer>\n"; |
164 | print "read $_[0] bytes: <$buffer>\n"; |
148 | }; |
165 | }; |
149 | |
166 | |
|
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167 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback |
|
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168 | |
|
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169 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
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170 | reading at byte offset C<$in_offset>, and starts writing at the current |
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171 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
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172 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
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173 | other. |
|
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174 | |
|
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175 | This call tries to make use of a native C<sendfile> syscall to provide |
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176 | zero-copy operation. For this to work, C<$out_fh> should refer to a |
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177 | socket, and C<$in_fh> should refer to mmap'able file. |
|
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178 | |
|
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179 | If the native sendfile call fails or is not implemented, it will be |
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180 | emulated, so you can call C<aio_sendfile> on any type of filehandle |
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181 | regardless of the limitations of the operating system. |
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182 | |
|
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183 | Please note, however, that C<aio_sendfile> can read more bytes from |
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184 | C<$in_fh> than are written, and there is no way to find out how many |
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185 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
|
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186 | provides the number of bytes written to C<$out_fh>. Only if the result |
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187 | value equals C<$length> one can assume that C<$length> bytes have been |
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188 | read. |
|
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189 | |
150 | =item aio_readahead $fh,$offset,$length, $callback |
190 | =item aio_readahead $fh,$offset,$length, $callback |
151 | |
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152 | Asynchronously reads the specified byte range into the page cache, using |
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153 | the C<readahead> syscall. If that syscall doesn't exist (likely if your OS |
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154 | isn't Linux) the status will be C<-1> and C<$!> is set to C<ENOSYS>. |
|
|
155 | |
191 | |
156 | C<aio_readahead> populates the page cache with data from a file so that |
192 | C<aio_readahead> populates the page cache with data from a file so that |
157 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
193 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
158 | argument specifies the starting point from which data is to be read and |
194 | argument specifies the starting point from which data is to be read and |
159 | C<$length> specifies the number of bytes to be read. I/O is performed in |
195 | C<$length> specifies the number of bytes to be read. I/O is performed in |
160 | whole pages, so that offset is effectively rounded down to a page boundary |
196 | whole pages, so that offset is effectively rounded down to a page boundary |
161 | and bytes are read up to the next page boundary greater than or equal to |
197 | and bytes are read up to the next page boundary greater than or equal to |
162 | (off-set+length). C<aio_readahead> does not read beyond the end of the |
198 | (off-set+length). C<aio_readahead> does not read beyond the end of the |
163 | file. The current file offset of the file is left unchanged. |
199 | file. The current file offset of the file is left unchanged. |
164 | |
200 | |
|
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201 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
|
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202 | emulated by simply reading the data, which would have a similar effect. |
|
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203 | |
165 | =item aio_stat $fh_or_path, $callback |
204 | =item aio_stat $fh_or_path, $callback |
166 | |
205 | |
167 | =item aio_lstat $fh, $callback |
206 | =item aio_lstat $fh, $callback |
168 | |
207 | |
169 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
208 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
… | |
… | |
187 | =item aio_unlink $pathname, $callback |
226 | =item aio_unlink $pathname, $callback |
188 | |
227 | |
189 | Asynchronously unlink (delete) a file and call the callback with the |
228 | Asynchronously unlink (delete) a file and call the callback with the |
190 | result code. |
229 | result code. |
191 | |
230 | |
|
|
231 | =item aio_rmdir $pathname, $callback |
|
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232 | |
|
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233 | Asynchronously rmdir (delete) a directory and call the callback with the |
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234 | result code. |
|
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235 | |
192 | =item aio_fsync $fh, $callback |
236 | =item aio_fsync $fh, $callback |
193 | |
237 | |
194 | Asynchronously call fsync on the given filehandle and call the callback |
238 | Asynchronously call fsync on the given filehandle and call the callback |
195 | with the fsync result code. |
239 | with the fsync result code. |
196 | |
240 | |
197 | =item aio_fdatasync $fh, $callback |
241 | =item aio_fdatasync $fh, $callback |
198 | |
242 | |
199 | Asynchronously call fdatasync on the given filehandle and call the |
243 | Asynchronously call fdatasync on the given filehandle and call the |
200 | callback with the fdatasync result code. Might set C<$!> to C<ENOSYS> if |
244 | callback with the fdatasync result code. |
201 | C<fdatasync> is not available. |
245 | |
|
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246 | If this call isn't available because your OS lacks it or it couldn't be |
|
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247 | detected, it will be emulated by calling C<fsync> instead. |
202 | |
248 | |
203 | =back |
249 | =back |
204 | |
250 | |
205 | =head2 SUPPORT FUNCTIONS |
251 | =head2 SUPPORT FUNCTIONS |
206 | |
252 | |
… | |
… | |
264 | IO::AIO::poll_wait, IO::AIO::poll_cb |
310 | IO::AIO::poll_wait, IO::AIO::poll_cb |
265 | if IO::AIO::nreqs; |
311 | if IO::AIO::nreqs; |
266 | |
312 | |
267 | =item IO::AIO::min_parallel $nthreads |
313 | =item IO::AIO::min_parallel $nthreads |
268 | |
314 | |
269 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
315 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
270 | C<1>, which means a single asynchronous operation can be done at one time |
316 | is C<4>, which means four asynchronous operations can be done at one time |
271 | (the number of outstanding operations, however, is unlimited). |
317 | (the number of outstanding operations, however, is unlimited). |
|
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318 | |
|
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319 | IO::AIO starts threads only on demand, when an AIO request is queued and |
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320 | no free thread exists. |
272 | |
321 | |
273 | It is recommended to keep the number of threads low, as some Linux |
322 | It is recommended to keep the number of threads low, as some Linux |
274 | kernel versions will scale negatively with the number of threads (higher |
323 | kernel versions will scale negatively with the number of threads (higher |
275 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
324 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
276 | threads should be fine. |
325 | threads should be fine. |
277 | |
326 | |
278 | Under normal circumstances you don't need to call this function, as this |
327 | Under most circumstances you don't need to call this function, as the |
279 | module automatically starts some threads (the exact number might change, |
328 | module selects a default that is suitable for low to moderate load. |
280 | and is currently 4). |
|
|
281 | |
329 | |
282 | =item IO::AIO::max_parallel $nthreads |
330 | =item IO::AIO::max_parallel $nthreads |
283 | |
331 | |
284 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
332 | Sets the maximum number of AIO threads to C<$nthreads>. If more than the |
285 | the specified number of threads are currently running, kill them. This |
333 | specified number of threads are currently running, this function kills |
286 | function blocks until the limit is reached. |
334 | them. This function blocks until the limit is reached. |
|
|
335 | |
|
|
336 | While C<$nthreads> are zero, aio requests get queued but not executed |
|
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337 | until the number of threads has been increased again. |
287 | |
338 | |
288 | This module automatically runs C<max_parallel 0> at program end, to ensure |
339 | This module automatically runs C<max_parallel 0> at program end, to ensure |
289 | that all threads are killed and that there are no outstanding requests. |
340 | that all threads are killed and that there are no outstanding requests. |
290 | |
341 | |
291 | Under normal circumstances you don't need to call this function. |
342 | Under normal circumstances you don't need to call this function. |
… | |
… | |
295 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
346 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
296 | try to queue up more than this number of requests, the caller will block until |
347 | try to queue up more than this number of requests, the caller will block until |
297 | some requests have been handled. |
348 | some requests have been handled. |
298 | |
349 | |
299 | The default is very large, so normally there is no practical limit. If you |
350 | The default is very large, so normally there is no practical limit. If you |
300 | queue up many requests in a loop it it often improves speed if you set |
351 | queue up many requests in a loop it often improves speed if you set |
301 | this to a relatively low number, such as C<100>. |
352 | this to a relatively low number, such as C<100>. |
302 | |
353 | |
303 | Under normal circumstances you don't need to call this function. |
354 | Under normal circumstances you don't need to call this function. |
304 | |
355 | |
305 | =back |
356 | =back |
… | |
… | |
308 | |
359 | |
309 | # support function to convert a fd into a perl filehandle |
360 | # support function to convert a fd into a perl filehandle |
310 | sub _fd2fh { |
361 | sub _fd2fh { |
311 | return undef if $_[0] < 0; |
362 | return undef if $_[0] < 0; |
312 | |
363 | |
313 | # try to be perl5.6-compatible |
364 | # try to generate nice filehandles |
314 | local *AIO_FH; |
365 | my $sym = "IO::AIO::fd#$_[0]"; |
315 | open AIO_FH, "+<&=$_[0]" |
366 | local *$sym; |
|
|
367 | |
|
|
368 | open *$sym, "+<&=$_[0]" # usually works under any unix |
|
|
369 | or open *$sym, "<&=$_[0]" # cygwin needs this |
|
|
370 | or open *$sym, ">&=$_[0]" # or this |
316 | or return undef; |
371 | or return undef; |
317 | |
372 | |
318 | *AIO_FH |
373 | *$sym |
319 | } |
374 | } |
320 | |
375 | |
321 | min_parallel 4; |
376 | min_parallel 4; |
322 | |
377 | |
323 | END { |
378 | END { |
324 | max_parallel 0; |
379 | max_parallel 0; |
325 | } |
380 | } |
326 | |
381 | |
327 | 1; |
382 | 1; |
328 | |
383 | |
|
|
384 | =head2 FORK BEHAVIOUR |
|
|
385 | |
|
|
386 | Before the fork, IO::AIO enters a quiescent state where no requests |
|
|
387 | can be added in other threads and no results will be processed. After |
|
|
388 | the fork the parent simply leaves the quiescent state and continues |
|
|
389 | request/result processing, while the child clears the request/result |
|
|
390 | queue (so the requests started before the fork will only be handled in |
|
|
391 | the parent). Threats will be started on demand until the limit ste in the |
|
|
392 | parent process has been reached again. |
|
|
393 | |
329 | =head1 SEE ALSO |
394 | =head1 SEE ALSO |
330 | |
395 | |
331 | L<Coro>, L<Linux::AIO>. |
396 | L<Coro>, L<Linux::AIO>. |
332 | |
397 | |
333 | =head1 AUTHOR |
398 | =head1 AUTHOR |