| … | |
… | |
| 2 | IO::AIO - Asynchronous Input/Output |
2 | IO::AIO - Asynchronous Input/Output |
| 3 | |
3 | |
| 4 | SYNOPSIS |
4 | SYNOPSIS |
| 5 | use IO::AIO; |
5 | use IO::AIO; |
| 6 | |
6 | |
| 7 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
7 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
| 8 | my $fh = shift |
8 | my $fh = shift |
| 9 | or die "/etc/passwd: $!"; |
9 | or die "/etc/passwd: $!"; |
| 10 | ... |
10 | ... |
| 11 | }; |
11 | }; |
| 12 | |
12 | |
| … | |
… | |
| 72 | |
72 | |
| 73 | # register the IO::AIO callback with EV |
73 | # register the IO::AIO callback with EV |
| 74 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
74 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
| 75 | |
75 | |
| 76 | # queue the request to open /etc/passwd |
76 | # queue the request to open /etc/passwd |
| 77 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
77 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
| 78 | my $fh = shift |
78 | my $fh = shift |
| 79 | or die "error while opening: $!"; |
79 | or die "error while opening: $!"; |
| 80 | |
80 | |
| 81 | # stat'ing filehandles is generally non-blocking |
81 | # stat'ing filehandles is generally non-blocking |
| 82 | my $size = -s $fh; |
82 | my $size = -s $fh; |
| … | |
… | |
| 150 | QUICK OVERVIEW |
150 | QUICK OVERVIEW |
| 151 | This section simply lists the prototypes of the most important functions |
151 | This section simply lists the prototypes of the most important functions |
| 152 | for quick reference. See the following sections for function-by-function |
152 | for quick reference. See the following sections for function-by-function |
| 153 | documentation. |
153 | documentation. |
| 154 | |
154 | |
|
|
155 | aio_wd $pathname, $callback->($wd) |
| 155 | aio_open $pathname, $flags, $mode, $callback->($fh) |
156 | aio_open $pathname, $flags, $mode, $callback->($fh) |
| 156 | aio_close $fh, $callback->($status) |
157 | aio_close $fh, $callback->($status) |
|
|
158 | aio_seek $fh,$offset,$whence, $callback->($offs) |
| 157 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
159 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
| 158 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
160 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
| 159 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
161 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
| 160 | aio_readahead $fh,$offset,$length, $callback->($retval) |
162 | aio_readahead $fh,$offset,$length, $callback->($retval) |
| 161 | aio_stat $fh_or_path, $callback->($status) |
163 | aio_stat $fh_or_path, $callback->($status) |
| 162 | aio_lstat $fh, $callback->($status) |
164 | aio_lstat $fh, $callback->($status) |
| 163 | aio_statvfs $fh_or_path, $callback->($statvfs) |
165 | aio_statvfs $fh_or_path, $callback->($statvfs) |
| 164 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
166 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
| 165 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
167 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
|
|
168 | aio_chmod $fh_or_path, $mode, $callback->($status) |
| 166 | aio_truncate $fh_or_path, $offset, $callback->($status) |
169 | aio_truncate $fh_or_path, $offset, $callback->($status) |
| 167 | aio_chmod $fh_or_path, $mode, $callback->($status) |
|
|
| 168 | aio_unlink $pathname, $callback->($status) |
170 | aio_unlink $pathname, $callback->($status) |
| 169 | aio_mknod $path, $mode, $dev, $callback->($status) |
171 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
| 170 | aio_link $srcpath, $dstpath, $callback->($status) |
172 | aio_link $srcpath, $dstpath, $callback->($status) |
| 171 | aio_symlink $srcpath, $dstpath, $callback->($status) |
173 | aio_symlink $srcpath, $dstpath, $callback->($status) |
| 172 | aio_readlink $path, $callback->($link) |
174 | aio_readlink $pathname, $callback->($link) |
|
|
175 | aio_realpath $pathname, $callback->($link) |
| 173 | aio_rename $srcpath, $dstpath, $callback->($status) |
176 | aio_rename $srcpath, $dstpath, $callback->($status) |
| 174 | aio_mkdir $pathname, $mode, $callback->($status) |
177 | aio_mkdir $pathname, $mode, $callback->($status) |
| 175 | aio_rmdir $pathname, $callback->($status) |
178 | aio_rmdir $pathname, $callback->($status) |
| 176 | aio_readdir $pathname, $callback->($entries) |
179 | aio_readdir $pathname, $callback->($entries) |
| 177 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
180 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
| 178 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
181 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
| 179 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
182 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
183 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
| 180 | aio_load $path, $data, $callback->($status) |
184 | aio_load $pathname, $data, $callback->($status) |
| 181 | aio_copy $srcpath, $dstpath, $callback->($status) |
185 | aio_copy $srcpath, $dstpath, $callback->($status) |
| 182 | aio_move $srcpath, $dstpath, $callback->($status) |
186 | aio_move $srcpath, $dstpath, $callback->($status) |
| 183 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
|
|
| 184 | aio_rmtree $path, $callback->($status) |
187 | aio_rmtree $pathname, $callback->($status) |
| 185 | aio_sync $callback->($status) |
188 | aio_sync $callback->($status) |
|
|
189 | aio_syncfs $fh, $callback->($status) |
| 186 | aio_fsync $fh, $callback->($status) |
190 | aio_fsync $fh, $callback->($status) |
| 187 | aio_fdatasync $fh, $callback->($status) |
191 | aio_fdatasync $fh, $callback->($status) |
| 188 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
192 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
| 189 | aio_pathsync $path, $callback->($status) |
193 | aio_pathsync $pathname, $callback->($status) |
| 190 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
194 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
| 191 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
195 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
196 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
197 | aio_mlockall $flags, $callback->($status) |
| 192 | aio_group $callback->(...) |
198 | aio_group $callback->(...) |
| 193 | aio_nop $callback->() |
199 | aio_nop $callback->() |
| 194 | |
200 | |
| 195 | $prev_pri = aioreq_pri [$pri] |
201 | $prev_pri = aioreq_pri [$pri] |
| 196 | aioreq_nice $pri_adjust |
202 | aioreq_nice $pri_adjust |
| … | |
… | |
| 202 | IO::AIO::max_poll_reqs $nreqs |
208 | IO::AIO::max_poll_reqs $nreqs |
| 203 | IO::AIO::max_poll_time $seconds |
209 | IO::AIO::max_poll_time $seconds |
| 204 | IO::AIO::min_parallel $nthreads |
210 | IO::AIO::min_parallel $nthreads |
| 205 | IO::AIO::max_parallel $nthreads |
211 | IO::AIO::max_parallel $nthreads |
| 206 | IO::AIO::max_idle $nthreads |
212 | IO::AIO::max_idle $nthreads |
|
|
213 | IO::AIO::idle_timeout $seconds |
| 207 | IO::AIO::max_outstanding $maxreqs |
214 | IO::AIO::max_outstanding $maxreqs |
| 208 | IO::AIO::nreqs |
215 | IO::AIO::nreqs |
| 209 | IO::AIO::nready |
216 | IO::AIO::nready |
| 210 | IO::AIO::npending |
217 | IO::AIO::npending |
| 211 | |
218 | |
| 212 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
219 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
| 213 | IO::AIO::fadvise $fh, $offset, $len, $advice |
220 | IO::AIO::fadvise $fh, $offset, $len, $advice |
| 214 | IO::AIO::mlockall $flags |
221 | IO::AIO::madvise $scalar, $offset, $length, $advice |
|
|
222 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
|
|
223 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
| 215 | IO::AIO::munlockall |
224 | IO::AIO::munlockall |
| 216 | |
225 | |
| 217 | AIO REQUEST FUNCTIONS |
226 | API NOTES |
| 218 | All the "aio_*" calls are more or less thin wrappers around the syscall |
227 | All the "aio_*" calls are more or less thin wrappers around the syscall |
| 219 | with the same name (sans "aio_"). The arguments are similar or |
228 | with the same name (sans "aio_"). The arguments are similar or |
| 220 | identical, and they all accept an additional (and optional) $callback |
229 | identical, and they all accept an additional (and optional) $callback |
| 221 | argument which must be a code reference. This code reference will get |
230 | argument which must be a code reference. This code reference will be |
| 222 | called with the syscall return code (e.g. most syscalls return -1 on |
|
|
| 223 | error, unlike perl, which usually delivers "false") as its sole argument |
|
|
| 224 | after the given syscall has been executed asynchronously. |
231 | called after the syscall has been executed in an asynchronous fashion. |
|
|
232 | The results of the request will be passed as arguments to the callback |
|
|
233 | (and, if an error occured, in $!) - for most requests the syscall return |
|
|
234 | code (e.g. most syscalls return -1 on error, unlike perl, which usually |
|
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235 | delivers "false"). |
|
|
236 | |
|
|
237 | Some requests (such as "aio_readdir") pass the actual results and |
|
|
238 | communicate failures by passing "undef". |
| 225 | |
239 | |
| 226 | All functions expecting a filehandle keep a copy of the filehandle |
240 | All functions expecting a filehandle keep a copy of the filehandle |
| 227 | internally until the request has finished. |
241 | internally until the request has finished. |
| 228 | |
242 | |
| 229 | All functions return request objects of type IO::AIO::REQ that allow |
243 | All functions return request objects of type IO::AIO::REQ that allow |
| 230 | further manipulation of those requests while they are in-flight. |
244 | further manipulation of those requests while they are in-flight. |
| 231 | |
245 | |
| 232 | The pathnames you pass to these routines *must* be absolute and encoded |
246 | The pathnames you pass to these routines *should* be absolute. The |
| 233 | as octets. The reason for the former is that at the time the request is |
247 | reason for this is that at the time the request is being executed, the |
| 234 | being executed, the current working directory could have changed. |
248 | current working directory could have changed. Alternatively, you can |
| 235 | Alternatively, you can make sure that you never change the current |
249 | make sure that you never change the current working directory anywhere |
| 236 | working directory anywhere in the program and then use relative paths. |
250 | in the program and then use relative paths. You can also take advantage |
|
|
251 | of IO::AIOs working directory abstraction, that lets you specify paths |
|
|
252 | relative to some previously-opened "working directory object" - see the |
|
|
253 | description of the "IO::AIO::WD" class later in this document. |
| 237 | |
254 | |
| 238 | To encode pathnames as octets, either make sure you either: a) always |
255 | To encode pathnames as octets, either make sure you either: a) always |
| 239 | pass in filenames you got from outside (command line, readdir etc.) |
256 | pass in filenames you got from outside (command line, readdir etc.) |
| 240 | without tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module |
257 | without tinkering, b) are in your native filesystem encoding, c) use the |
| 241 | and encode your pathnames to the locale (or other) encoding in effect in |
258 | Encode module and encode your pathnames to the locale (or other) |
| 242 | the user environment, d) use Glib::filename_from_unicode on unicode |
259 | encoding in effect in the user environment, d) use |
| 243 | filenames or e) use something else to ensure your scalar has the correct |
260 | Glib::filename_from_unicode on unicode filenames or e) use something |
| 244 | contents. |
261 | else to ensure your scalar has the correct contents. |
| 245 | |
262 | |
| 246 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
263 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
| 247 | handles correctly whether it is set or not. |
264 | handles correctly whether it is set or not. |
| 248 | |
265 | |
|
|
266 | AIO REQUEST FUNCTIONS |
| 249 | $prev_pri = aioreq_pri [$pri] |
267 | $prev_pri = aioreq_pri [$pri] |
| 250 | Returns the priority value that would be used for the next request |
268 | Returns the priority value that would be used for the next request |
| 251 | and, if $pri is given, sets the priority for the next aio request. |
269 | and, if $pri is given, sets the priority for the next aio request. |
| 252 | |
270 | |
| 253 | The default priority is 0, the minimum and maximum priorities are -4 |
271 | The default priority is 0, the minimum and maximum priorities are -4 |
| … | |
… | |
| 292 | will be modified by the umask in effect then the request is being |
310 | will be modified by the umask in effect then the request is being |
| 293 | executed, so better never change the umask. |
311 | executed, so better never change the umask. |
| 294 | |
312 | |
| 295 | Example: |
313 | Example: |
| 296 | |
314 | |
| 297 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
315 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
| 298 | if ($_[0]) { |
316 | if ($_[0]) { |
| 299 | print "open successful, fh is $_[0]\n"; |
317 | print "open successful, fh is $_[0]\n"; |
| 300 | ... |
318 | ... |
| 301 | } else { |
319 | } else { |
| 302 | die "open failed: $!\n"; |
320 | die "open failed: $!\n"; |
| 303 | } |
321 | } |
| 304 | }; |
322 | }; |
| 305 | |
323 | |
|
|
324 | In addition to all the common open modes/flags ("O_RDONLY", |
|
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325 | "O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and |
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326 | "O_APPEND"), the following POSIX and non-POSIX constants are |
|
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327 | available (missing ones on your system are, as usual, 0): |
|
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328 | |
|
|
329 | "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", |
|
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330 | "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", |
|
|
331 | "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT". |
|
|
332 | |
| 306 | aio_close $fh, $callback->($status) |
333 | aio_close $fh, $callback->($status) |
| 307 | Asynchronously close a file and call the callback with the result |
334 | Asynchronously close a file and call the callback with the result |
| 308 | code. |
335 | code. |
| 309 | |
336 | |
| 310 | Unfortunately, you can't do this to perl. Perl *insists* very |
337 | Unfortunately, you can't do this to perl. Perl *insists* very |
| … | |
… | |
| 315 | will use dup2 to overwrite the file descriptor with the write-end of |
342 | will use dup2 to overwrite the file descriptor with the write-end of |
| 316 | a pipe (the pipe fd will be created on demand and will be cached). |
343 | a pipe (the pipe fd will be created on demand and will be cached). |
| 317 | |
344 | |
| 318 | Or in other words: the file descriptor will be closed, but it will |
345 | Or in other words: the file descriptor will be closed, but it will |
| 319 | not be free for reuse until the perl filehandle is closed. |
346 | not be free for reuse until the perl filehandle is closed. |
|
|
347 | |
|
|
348 | aio_seek $fh, $offset, $whence, $callback->($offs) |
|
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349 | Seeks the filehandle to the new $offset, similarly to perl's |
|
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350 | "sysseek". The $whence can use the traditional values (0 for |
|
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351 | "IO::AIO::SEEK_SET", 1 for "IO::AIO::SEEK_CUR" or 2 for |
|
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352 | "IO::AIO::SEEK_END"). |
|
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353 | |
|
|
354 | The resulting absolute offset will be passed to the callback, or -1 |
|
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355 | in case of an error. |
|
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356 | |
|
|
357 | In theory, the $whence constants could be different than the |
|
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358 | corresponding values from Fcntl, but perl guarantees they are the |
|
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359 | same, so don't panic. |
|
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360 | |
|
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361 | As a GNU/Linux (and maybe Solaris) extension, also the constants |
|
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362 | "IO::AIO::SEEK_DATA" and "IO::AIO::SEEK_HOLE" are available, if they |
|
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363 | could be found. No guarantees about suitability for use in |
|
|
364 | "aio_seek" or Perl's "sysseek" can be made though, although I would |
|
|
365 | naively assume they "just work". |
| 320 | |
366 | |
| 321 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
367 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
| 322 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
368 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
| 323 | Reads or writes $length bytes from or to the specified $fh and |
369 | Reads or writes $length bytes from or to the specified $fh and |
| 324 | $offset into the scalar given by $data and offset $dataoffset and |
370 | $offset into the scalar given by $data and offset $dataoffset and |
| … | |
… | |
| 353 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
399 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
| 354 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
400 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
| 355 | reading at byte offset $in_offset, and starts writing at the current |
401 | reading at byte offset $in_offset, and starts writing at the current |
| 356 | file offset of $out_fh. Because of that, it is not safe to issue |
402 | file offset of $out_fh. Because of that, it is not safe to issue |
| 357 | more than one "aio_sendfile" per $out_fh, as they will interfere |
403 | more than one "aio_sendfile" per $out_fh, as they will interfere |
| 358 | with each other. |
404 | with each other. The same $in_fh works fine though, as this function |
|
|
405 | does not move or use the file offset of $in_fh. |
| 359 | |
406 | |
|
|
407 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
|
|
408 | are written, and there is no way to find out how many more bytes |
|
|
409 | have been read from "aio_sendfile" alone, as "aio_sendfile" only |
|
|
410 | provides the number of bytes written to $out_fh. Only if the result |
|
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411 | value equals $length one can assume that $length bytes have been |
|
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412 | read. |
|
|
413 | |
|
|
414 | Unlike with other "aio_" functions, it makes a lot of sense to use |
|
|
415 | "aio_sendfile" on non-blocking sockets, as long as one end |
|
|
416 | (typically the $in_fh) is a file - the file I/O will then be |
|
|
417 | asynchronous, while the socket I/O will be non-blocking. Note, |
|
|
418 | however, that you can run into a trap where "aio_sendfile" reads |
|
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419 | some data with readahead, then fails to write all data, and when the |
|
|
420 | socket is ready the next time, the data in the cache is already |
|
|
421 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
|
|
422 | "aio_read" + "aio_write" let's you better control resource usage. |
|
|
423 | |
| 360 | This call tries to make use of a native "sendfile" syscall to |
424 | This call tries to make use of a native "sendfile"-like syscall to |
| 361 | provide zero-copy operation. For this to work, $out_fh should refer |
425 | provide zero-copy operation. For this to work, $out_fh should refer |
| 362 | to a socket, and $in_fh should refer to an mmap'able file. |
426 | to a socket, and $in_fh should refer to an mmap'able file. |
| 363 | |
427 | |
| 364 | If a native sendfile cannot be found or it fails with "ENOSYS", |
428 | If a native sendfile cannot be found or it fails with "ENOSYS", |
| 365 | "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK", |
429 | "EINVAL", "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or |
| 366 | it will be emulated, so you can call "aio_sendfile" on any type of |
430 | "ENOTSOCK", it will be emulated, so you can call "aio_sendfile" on |
| 367 | filehandle regardless of the limitations of the operating system. |
431 | any type of filehandle regardless of the limitations of the |
|
|
432 | operating system. |
| 368 | |
433 | |
| 369 | Please note, however, that "aio_sendfile" can read more bytes from |
434 | As native sendfile syscalls (as practically any non-POSIX interface |
| 370 | $in_fh than are written, and there is no way to find out how many |
435 | hacked together in a hurry to improve benchmark numbers) tend to be |
| 371 | bytes have been read from "aio_sendfile" alone, as "aio_sendfile" |
436 | rather buggy on many systems, this implementation tries to work |
| 372 | only provides the number of bytes written to $out_fh. Only if the |
437 | around some known bugs in Linux and FreeBSD kernels (probably |
| 373 | result value equals $length one can assume that $length bytes have |
438 | others, too), but that might fail, so you really really should check |
| 374 | been read. |
439 | the return value of "aio_sendfile" - fewre bytes than expected might |
|
|
440 | have been transferred. |
| 375 | |
441 | |
| 376 | aio_readahead $fh,$offset,$length, $callback->($retval) |
442 | aio_readahead $fh,$offset,$length, $callback->($retval) |
| 377 | "aio_readahead" populates the page cache with data from a file so |
443 | "aio_readahead" populates the page cache with data from a file so |
| 378 | that subsequent reads from that file will not block on disk I/O. The |
444 | that subsequent reads from that file will not block on disk I/O. The |
| 379 | $offset argument specifies the starting point from which data is to |
445 | $offset argument specifies the starting point from which data is to |
| … | |
… | |
| 399 | |
465 | |
| 400 | Currently, the stats are always 64-bit-stats, i.e. instead of |
466 | Currently, the stats are always 64-bit-stats, i.e. instead of |
| 401 | returning an error when stat'ing a large file, the results will be |
467 | returning an error when stat'ing a large file, the results will be |
| 402 | silently truncated unless perl itself is compiled with large file |
468 | silently truncated unless perl itself is compiled with large file |
| 403 | support. |
469 | support. |
|
|
470 | |
|
|
471 | To help interpret the mode and dev/rdev stat values, IO::AIO offers |
|
|
472 | the following constants and functions (if not implemented, the |
|
|
473 | constants will be 0 and the functions will either "croak" or fall |
|
|
474 | back on traditional behaviour). |
|
|
475 | |
|
|
476 | "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", |
|
|
477 | "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", |
|
|
478 | "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". |
| 404 | |
479 | |
| 405 | Example: Print the length of /etc/passwd: |
480 | Example: Print the length of /etc/passwd: |
| 406 | |
481 | |
| 407 | aio_stat "/etc/passwd", sub { |
482 | aio_stat "/etc/passwd", sub { |
| 408 | $_[0] and die "stat failed: $!"; |
483 | $_[0] and die "stat failed: $!"; |
| … | |
… | |
| 488 | |
563 | |
| 489 | aio_unlink $pathname, $callback->($status) |
564 | aio_unlink $pathname, $callback->($status) |
| 490 | Asynchronously unlink (delete) a file and call the callback with the |
565 | Asynchronously unlink (delete) a file and call the callback with the |
| 491 | result code. |
566 | result code. |
| 492 | |
567 | |
| 493 | aio_mknod $path, $mode, $dev, $callback->($status) |
568 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
| 494 | [EXPERIMENTAL] |
569 | [EXPERIMENTAL] |
| 495 | |
570 | |
| 496 | Asynchronously create a device node (or fifo). See mknod(2). |
571 | Asynchronously create a device node (or fifo). See mknod(2). |
| 497 | |
572 | |
| 498 | The only (POSIX-) portable way of calling this function is: |
573 | The only (POSIX-) portable way of calling this function is: |
| 499 | |
574 | |
| 500 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
575 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
576 | |
|
|
577 | See "aio_stat" for info about some potentially helpful extra |
|
|
578 | constants and functions. |
| 501 | |
579 | |
| 502 | aio_link $srcpath, $dstpath, $callback->($status) |
580 | aio_link $srcpath, $dstpath, $callback->($status) |
| 503 | Asynchronously create a new link to the existing object at $srcpath |
581 | Asynchronously create a new link to the existing object at $srcpath |
| 504 | at the path $dstpath and call the callback with the result code. |
582 | at the path $dstpath and call the callback with the result code. |
| 505 | |
583 | |
| 506 | aio_symlink $srcpath, $dstpath, $callback->($status) |
584 | aio_symlink $srcpath, $dstpath, $callback->($status) |
| 507 | Asynchronously create a new symbolic link to the existing object at |
585 | Asynchronously create a new symbolic link to the existing object at |
| 508 | $srcpath at the path $dstpath and call the callback with the result |
586 | $srcpath at the path $dstpath and call the callback with the result |
| 509 | code. |
587 | code. |
| 510 | |
588 | |
| 511 | aio_readlink $path, $callback->($link) |
589 | aio_readlink $pathname, $callback->($link) |
| 512 | Asynchronously read the symlink specified by $path and pass it to |
590 | Asynchronously read the symlink specified by $path and pass it to |
| 513 | the callback. If an error occurs, nothing or undef gets passed to |
591 | the callback. If an error occurs, nothing or undef gets passed to |
| 514 | the callback. |
592 | the callback. |
|
|
593 | |
|
|
594 | aio_realpath $pathname, $callback->($path) |
|
|
595 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
596 | $path. The resulting path only consists of directories (Same as |
|
|
597 | Cwd::realpath). |
|
|
598 | |
|
|
599 | This request can be used to get the absolute path of the current |
|
|
600 | working directory by passing it a path of . (a single dot). |
| 515 | |
601 | |
| 516 | aio_rename $srcpath, $dstpath, $callback->($status) |
602 | aio_rename $srcpath, $dstpath, $callback->($status) |
| 517 | Asynchronously rename the object at $srcpath to $dstpath, just as |
603 | Asynchronously rename the object at $srcpath to $dstpath, just as |
| 518 | rename(2) and call the callback with the result code. |
604 | rename(2) and call the callback with the result code. |
| 519 | |
605 | |
| … | |
… | |
| 533 | |
619 | |
| 534 | The callback is passed a single argument which is either "undef" or |
620 | The callback is passed a single argument which is either "undef" or |
| 535 | an array-ref with the filenames. |
621 | an array-ref with the filenames. |
| 536 | |
622 | |
| 537 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
623 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
| 538 | Quite similar to "aio_readdir", but the $flags argument allows to |
624 | Quite similar to "aio_readdir", but the $flags argument allows one |
| 539 | tune behaviour and output format. In case of an error, $entries will |
625 | to tune behaviour and output format. In case of an error, $entries |
| 540 | be "undef". |
626 | will be "undef". |
| 541 | |
627 | |
| 542 | The flags are a combination of the following constants, ORed |
628 | The flags are a combination of the following constants, ORed |
| 543 | together (the flags will also be passed to the callback, possibly |
629 | together (the flags will also be passed to the callback, possibly |
| 544 | modified): |
630 | modified): |
| 545 | |
631 | |
| 546 | IO::AIO::READDIR_DENTS |
632 | IO::AIO::READDIR_DENTS |
| 547 | When this flag is off, then the callback gets an arrayref with |
633 | When this flag is off, then the callback gets an arrayref |
| 548 | of names only (as with "aio_readdir"), otherwise it gets an |
634 | consisting of names only (as with "aio_readdir"), otherwise it |
| 549 | arrayref with "[$name, $type, $inode]" arrayrefs, each |
635 | gets an arrayref with "[$name, $type, $inode]" arrayrefs, each |
| 550 | describing a single directory entry in more detail. |
636 | describing a single directory entry in more detail. |
| 551 | |
637 | |
| 552 | $name is the name of the entry. |
638 | $name is the name of the entry. |
| 553 | |
639 | |
| 554 | $type is one of the "IO::AIO::DT_xxx" constants: |
640 | $type is one of the "IO::AIO::DT_xxx" constants: |
| … | |
… | |
| 567 | unspecified content on systems that do not deliver the inode |
653 | unspecified content on systems that do not deliver the inode |
| 568 | information. |
654 | information. |
| 569 | |
655 | |
| 570 | IO::AIO::READDIR_DIRS_FIRST |
656 | IO::AIO::READDIR_DIRS_FIRST |
| 571 | When this flag is set, then the names will be returned in an |
657 | When this flag is set, then the names will be returned in an |
| 572 | order where likely directories come first. This is useful when |
658 | order where likely directories come first, in optimal stat |
| 573 | you need to quickly find directories, or you want to find all |
659 | order. This is useful when you need to quickly find directories, |
| 574 | directories while avoiding to stat() each entry. |
660 | or you want to find all directories while avoiding to stat() |
|
|
661 | each entry. |
| 575 | |
662 | |
| 576 | If the system returns type information in readdir, then this is |
663 | If the system returns type information in readdir, then this is |
| 577 | used to find directories directly. Otherwise, likely directories |
664 | used to find directories directly. Otherwise, likely directories |
| 578 | are files beginning with ".", or otherwise files with no dots, |
665 | are names beginning with ".", or otherwise names with no dots, |
| 579 | of which files with short names are tried first. |
666 | of which names with short names are tried first. |
| 580 | |
667 | |
| 581 | IO::AIO::READDIR_STAT_ORDER |
668 | IO::AIO::READDIR_STAT_ORDER |
| 582 | When this flag is set, then the names will be returned in an |
669 | When this flag is set, then the names will be returned in an |
| 583 | order suitable for stat()'ing each one. That is, when you plan |
670 | order suitable for stat()'ing each one. That is, when you plan |
| 584 | to stat() all files in the given directory, then the returned |
671 | to stat() all files in the given directory, then the returned |
| … | |
… | |
| 589 | optimal stat order. |
676 | optimal stat order. |
| 590 | |
677 | |
| 591 | IO::AIO::READDIR_FOUND_UNKNOWN |
678 | IO::AIO::READDIR_FOUND_UNKNOWN |
| 592 | This flag should not be set when calling "aio_readdirx". |
679 | This flag should not be set when calling "aio_readdirx". |
| 593 | Instead, it is being set by "aio_readdirx", when any of the |
680 | Instead, it is being set by "aio_readdirx", when any of the |
| 594 | $type's found were "IO::AIO::DT_UNKNOWN". The absense of this |
681 | $type's found were "IO::AIO::DT_UNKNOWN". The absence of this |
| 595 | flag therefore indicates that all $type's are known, which can |
682 | flag therefore indicates that all $type's are known, which can |
| 596 | be used to speed up some algorithms. |
683 | be used to speed up some algorithms. |
| 597 | |
684 | |
| 598 | aio_load $path, $data, $callback->($status) |
685 | aio_load $pathname, $data, $callback->($status) |
| 599 | This is a composite request that tries to fully load the given file |
686 | This is a composite request that tries to fully load the given file |
| 600 | into memory. Status is the same as with aio_read. |
687 | into memory. Status is the same as with aio_read. |
| 601 | |
688 | |
| 602 | aio_copy $srcpath, $dstpath, $callback->($status) |
689 | aio_copy $srcpath, $dstpath, $callback->($status) |
| 603 | Try to copy the *file* (directories not supported as either source |
690 | Try to copy the *file* (directories not supported as either source |
| … | |
… | |
| 620 | |
707 | |
| 621 | This is a composite request that tries to rename(2) the file first; |
708 | This is a composite request that tries to rename(2) the file first; |
| 622 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
709 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
| 623 | and, if that is successful, unlinks the $srcpath. |
710 | and, if that is successful, unlinks the $srcpath. |
| 624 | |
711 | |
| 625 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
712 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
| 626 | Scans a directory (similar to "aio_readdir") but additionally tries |
713 | Scans a directory (similar to "aio_readdir") but additionally tries |
| 627 | to efficiently separate the entries of directory $path into two sets |
714 | to efficiently separate the entries of directory $path into two sets |
| 628 | of names, directories you can recurse into (directories), and ones |
715 | of names, directories you can recurse into (directories), and ones |
| 629 | you cannot recurse into (everything else, including symlinks to |
716 | you cannot recurse into (everything else, including symlinks to |
| 630 | directories). |
717 | directories). |
| … | |
… | |
| 663 | Then entries will be sorted into likely directories a non-initial |
750 | Then entries will be sorted into likely directories a non-initial |
| 664 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
751 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
| 665 | every entry plus an appended "/." will be "stat"'ed, likely |
752 | every entry plus an appended "/." will be "stat"'ed, likely |
| 666 | directories first, in order of their inode numbers. If that |
753 | directories first, in order of their inode numbers. If that |
| 667 | succeeds, it assumes that the entry is a directory or a symlink to |
754 | succeeds, it assumes that the entry is a directory or a symlink to |
| 668 | directory (which will be checked seperately). This is often faster |
755 | directory (which will be checked separately). This is often faster |
| 669 | than stat'ing the entry itself because filesystems might detect the |
756 | than stat'ing the entry itself because filesystems might detect the |
| 670 | type of the entry without reading the inode data (e.g. ext2fs |
757 | type of the entry without reading the inode data (e.g. ext2fs |
| 671 | filetype feature), even on systems that cannot return the filetype |
758 | filetype feature), even on systems that cannot return the filetype |
| 672 | information on readdir. |
759 | information on readdir. |
| 673 | |
760 | |
| … | |
… | |
| 679 | |
766 | |
| 680 | It will also likely work on non-POSIX filesystems with reduced |
767 | It will also likely work on non-POSIX filesystems with reduced |
| 681 | efficiency as those tend to return 0 or 1 as link counts, which |
768 | efficiency as those tend to return 0 or 1 as link counts, which |
| 682 | disables the directory counting heuristic. |
769 | disables the directory counting heuristic. |
| 683 | |
770 | |
| 684 | aio_rmtree $path, $callback->($status) |
771 | aio_rmtree $pathname, $callback->($status) |
| 685 | Delete a directory tree starting (and including) $path, return the |
772 | Delete a directory tree starting (and including) $path, return the |
| 686 | status of the final "rmdir" only. This is a composite request that |
773 | status of the final "rmdir" only. This is a composite request that |
| 687 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
774 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
| 688 | everything else. |
775 | everything else. |
| 689 | |
776 | |
| … | |
… | |
| 698 | Asynchronously call fdatasync on the given filehandle and call the |
785 | Asynchronously call fdatasync on the given filehandle and call the |
| 699 | callback with the fdatasync result code. |
786 | callback with the fdatasync result code. |
| 700 | |
787 | |
| 701 | If this call isn't available because your OS lacks it or it couldn't |
788 | If this call isn't available because your OS lacks it or it couldn't |
| 702 | be detected, it will be emulated by calling "fsync" instead. |
789 | be detected, it will be emulated by calling "fsync" instead. |
|
|
790 | |
|
|
791 | aio_syncfs $fh, $callback->($status) |
|
|
792 | Asynchronously call the syncfs syscall to sync the filesystem |
|
|
793 | associated to the given filehandle and call the callback with the |
|
|
794 | syncfs result code. If syncfs is not available, calls sync(), but |
|
|
795 | returns -1 and sets errno to "ENOSYS" nevertheless. |
| 703 | |
796 | |
| 704 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
797 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
| 705 | Sync the data portion of the file specified by $offset and $length |
798 | Sync the data portion of the file specified by $offset and $length |
| 706 | to disk (but NOT the metadata), by calling the Linux-specific |
799 | to disk (but NOT the metadata), by calling the Linux-specific |
| 707 | sync_file_range call. If sync_file_range is not available or it |
800 | sync_file_range call. If sync_file_range is not available or it |
| … | |
… | |
| 711 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
804 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
| 712 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
805 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
| 713 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
806 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
| 714 | manpage for details. |
807 | manpage for details. |
| 715 | |
808 | |
| 716 | aio_pathsync $path, $callback->($status) |
809 | aio_pathsync $pathname, $callback->($status) |
| 717 | This request tries to open, fsync and close the given path. This is |
810 | This request tries to open, fsync and close the given path. This is |
| 718 | a composite request intended to sync directories after directory |
811 | a composite request intended to sync directories after directory |
| 719 | operations (E.g. rename). This might not work on all operating |
812 | operations (E.g. rename). This might not work on all operating |
| 720 | systems or have any specific effect, but usually it makes sure that |
813 | systems or have any specific effect, but usually it makes sure that |
| 721 | directory changes get written to disc. It works for anything that |
814 | directory changes get written to disc. It works for anything that |
| … | |
… | |
| 751 | "aio_msync", above, except for flags, which must be either 0 (which |
844 | "aio_msync", above, except for flags, which must be either 0 (which |
| 752 | reads all pages and ensures they are instantiated) or |
845 | reads all pages and ensures they are instantiated) or |
| 753 | "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading |
846 | "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading |
| 754 | and writing an octet from it, which dirties the page). |
847 | and writing an octet from it, which dirties the page). |
| 755 | |
848 | |
|
|
849 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
850 | This is a rather advanced IO::AIO call, which works best on |
|
|
851 | mmap(2)ed scalars. |
|
|
852 | |
|
|
853 | It reads in all the pages of the underlying storage into memory (if |
|
|
854 | any) and locks them, so they are not getting swapped/paged out or |
|
|
855 | removed. |
|
|
856 | |
|
|
857 | If $length is undefined, then the scalar will be locked till the |
|
|
858 | end. |
|
|
859 | |
|
|
860 | On systems that do not implement "mlock", this function returns -1 |
|
|
861 | and sets errno to "ENOSYS". |
|
|
862 | |
|
|
863 | Note that the corresponding "munlock" is synchronous and is |
|
|
864 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
865 | |
|
|
866 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
867 | $data gets destroyed. |
|
|
868 | |
|
|
869 | open my $fh, "<", $path or die "$path: $!"; |
|
|
870 | my $data; |
|
|
871 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
872 | aio_mlock $data; # mlock in background |
|
|
873 | |
|
|
874 | aio_mlockall $flags, $callback->($status) |
|
|
875 | Calls the "mlockall" function with the given $flags (a combination |
|
|
876 | of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). |
|
|
877 | |
|
|
878 | On systems that do not implement "mlockall", this function returns |
|
|
879 | -1 and sets errno to "ENOSYS". |
|
|
880 | |
|
|
881 | Note that the corresponding "munlockall" is synchronous and is |
|
|
882 | documented under "MISCELLANEOUS FUNCTIONS". |
|
|
883 | |
|
|
884 | Example: asynchronously lock all current and future pages into |
|
|
885 | memory. |
|
|
886 | |
|
|
887 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
888 | |
|
|
889 | aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
|
|
890 | Queries the extents of the given file (by calling the Linux FIEMAP |
|
|
891 | ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for |
|
|
892 | details). If the "ioctl" is not available on your OS, then this |
|
|
893 | rquiest will fail with "ENOSYS". |
|
|
894 | |
|
|
895 | $start is the starting offset to query extents for, $length is the |
|
|
896 | size of the range to query - if it is "undef", then the whole file |
|
|
897 | will be queried. |
|
|
898 | |
|
|
899 | $flags is a combination of flags ("IO::AIO::FIEMAP_FLAG_SYNC" or |
|
|
900 | "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is |
|
|
901 | also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to |
|
|
902 | query the data portion. |
|
|
903 | |
|
|
904 | $count is the maximum number of extent records to return. If it is |
|
|
905 | "undef", then IO::AIO queries all extents of the file. As a very |
|
|
906 | special case, if it is 0, then the callback receives the number of |
|
|
907 | extents instead of the extents themselves. |
|
|
908 | |
|
|
909 | If an error occurs, the callback receives no arguments. The special |
|
|
910 | "errno" value "IO::AIO::EBADR" is available to test for flag errors. |
|
|
911 | |
|
|
912 | Otherwise, the callback receives an array reference with extent |
|
|
913 | structures. Each extent structure is an array reference itself, with |
|
|
914 | the following members: |
|
|
915 | |
|
|
916 | [$logical, $physical, $length, $flags] |
|
|
917 | |
|
|
918 | Flags is any combination of the following flag values (typically |
|
|
919 | either 0 or "IO::AIO::FIEMAP_EXTENT_LAST"): |
|
|
920 | |
|
|
921 | "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN", |
|
|
922 | "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED", |
|
|
923 | "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED", |
|
|
924 | "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED", |
|
|
925 | "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", |
|
|
926 | "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", |
|
|
927 | "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" |
|
|
928 | or "IO::AIO::FIEMAP_EXTENT_SHARED". |
|
|
929 | |
| 756 | aio_group $callback->(...) |
930 | aio_group $callback->(...) |
| 757 | This is a very special aio request: Instead of doing something, it |
931 | This is a very special aio request: Instead of doing something, it |
| 758 | is a container for other aio requests, which is useful if you want |
932 | is a container for other aio requests, which is useful if you want |
| 759 | to bundle many requests into a single, composite, request with a |
933 | to bundle many requests into a single, composite, request with a |
| 760 | definite callback and the ability to cancel the whole request with |
934 | definite callback and the ability to cancel the whole request with |
| … | |
… | |
| 793 | While it is theoretically handy to have simple I/O scheduling |
967 | While it is theoretically handy to have simple I/O scheduling |
| 794 | requests like sleep and file handle readable/writable, the overhead |
968 | requests like sleep and file handle readable/writable, the overhead |
| 795 | this creates is immense (it blocks a thread for a long time) so do |
969 | this creates is immense (it blocks a thread for a long time) so do |
| 796 | not use this function except to put your application under |
970 | not use this function except to put your application under |
| 797 | artificial I/O pressure. |
971 | artificial I/O pressure. |
|
|
972 | |
|
|
973 | IO::AIO::WD - multiple working directories |
|
|
974 | Your process only has one current working directory, which is used by |
|
|
975 | all threads. This makes it hard to use relative paths (some other |
|
|
976 | component could call "chdir" at any time, and it is hard to control when |
|
|
977 | the path will be used by IO::AIO). |
|
|
978 | |
|
|
979 | One solution for this is to always use absolute paths. This usually |
|
|
980 | works, but can be quite slow (the kernel has to walk the whole path on |
|
|
981 | every access), and can also be a hassle to implement. |
|
|
982 | |
|
|
983 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
984 | futimensat and so on) that make it possible to specify working |
|
|
985 | directories per operation. |
|
|
986 | |
|
|
987 | For portability, and because the clowns who "designed", or shall I |
|
|
988 | write, perpetrated this new interface were obviously half-drunk, this |
|
|
989 | abstraction cannot be perfect, though. |
|
|
990 | |
|
|
991 | IO::AIO allows you to convert directory paths into a so-called |
|
|
992 | IO::AIO::WD object. This object stores the canonicalised, absolute |
|
|
993 | version of the path, and on systems that allow it, also a directory file |
|
|
994 | descriptor. |
|
|
995 | |
|
|
996 | Everywhere where a pathname is accepted by IO::AIO (e.g. in "aio_stat" |
|
|
997 | or "aio_unlink"), one can specify an array reference with an IO::AIO::WD |
|
|
998 | object and a pathname instead (or the IO::AIO::WD object alone, which |
|
|
999 | gets interpreted as "[$wd, "."]"). If the pathname is absolute, the |
|
|
1000 | IO::AIO::WD object is ignored, otherwise the pathname is resolved |
|
|
1001 | relative to that IO::AIO::WD object. |
|
|
1002 | |
|
|
1003 | For example, to get a wd object for /etc and then stat passwd inside, |
|
|
1004 | you would write: |
|
|
1005 | |
|
|
1006 | aio_wd "/etc", sub { |
|
|
1007 | my $etcdir = shift; |
|
|
1008 | |
|
|
1009 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1010 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1011 | # when $etcdir is undef. |
|
|
1012 | |
|
|
1013 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1014 | # yay |
|
|
1015 | }; |
|
|
1016 | }; |
|
|
1017 | |
|
|
1018 | That "aio_wd" is a request and not a normal function shows that creating |
|
|
1019 | an IO::AIO::WD object is itself a potentially blocking operation, which |
|
|
1020 | is why it is done asynchronously. |
|
|
1021 | |
|
|
1022 | To stat the directory obtained with "aio_wd" above, one could write |
|
|
1023 | either of the following three request calls: |
|
|
1024 | |
|
|
1025 | aio_lstat "/etc" , sub { ... # pathname as normal string |
|
|
1026 | aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself) |
|
|
1027 | aio_lstat $wd , sub { ... # shorthand for the previous |
|
|
1028 | |
|
|
1029 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1030 | object and the pathname string, so you could write the following without |
|
|
1031 | causing any issues due to $path getting reused: |
|
|
1032 | |
|
|
1033 | my $path = [$wd, undef]; |
|
|
1034 | |
|
|
1035 | for my $name (qw(abc def ghi)) { |
|
|
1036 | $path->[1] = $name; |
|
|
1037 | aio_stat $path, sub { |
|
|
1038 | # ... |
|
|
1039 | }; |
|
|
1040 | } |
|
|
1041 | |
|
|
1042 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1043 | pathname string doesn't change, so will point to the new directory (or |
|
|
1044 | nowhere at all), while the directory fd, if available on the system, |
|
|
1045 | will still point to the original directory. Most functions accepting a |
|
|
1046 | pathname will use the directory fd on newer systems, and the string on |
|
|
1047 | older systems. Some functions (such as realpath) will always rely on the |
|
|
1048 | string form of the pathname. |
|
|
1049 | |
|
|
1050 | So this fucntionality is mainly useful to get some protection against |
|
|
1051 | "chdir", to easily get an absolute path out of a relative path for |
|
|
1052 | future reference, and to speed up doing many operations in the same |
|
|
1053 | directory (e.g. when stat'ing all files in a directory). |
|
|
1054 | |
|
|
1055 | The following functions implement this working directory abstraction: |
|
|
1056 | |
|
|
1057 | aio_wd $pathname, $callback->($wd) |
|
|
1058 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1059 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1060 | system, also open a directory fd to speed up pathname resolution |
|
|
1061 | relative to this working directory. |
|
|
1062 | |
|
|
1063 | If something goes wrong, then "undef" is passwd to the callback |
|
|
1064 | instead of a working directory object and $! is set appropriately. |
|
|
1065 | Since passing "undef" as working directory component of a pathname |
|
|
1066 | fails the request with "ENOENT", there is often no need for error |
|
|
1067 | checking in the "aio_wd" callback, as future requests using the |
|
|
1068 | value will fail in the expected way. |
|
|
1069 | |
|
|
1070 | If this call isn't available because your OS lacks it or it couldn't |
|
|
1071 | be detected, it will be emulated by calling "fsync" instead. |
|
|
1072 | |
|
|
1073 | IO::AIO::CWD |
|
|
1074 | This is a compiletime constant (object) that represents the process |
|
|
1075 | current working directory. |
|
|
1076 | |
|
|
1077 | Specifying this object as working directory object for a pathname is |
|
|
1078 | as if the pathname would be specified directly, without a directory |
|
|
1079 | object, e.g., these calls are functionally identical: |
|
|
1080 | |
|
|
1081 | aio_stat "somefile", sub { ... }; |
|
|
1082 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
| 798 | |
1083 | |
| 799 | IO::AIO::REQ CLASS |
1084 | IO::AIO::REQ CLASS |
| 800 | All non-aggregate "aio_*" functions return an object of this class when |
1085 | All non-aggregate "aio_*" functions return an object of this class when |
| 801 | called in non-void context. |
1086 | called in non-void context. |
| 802 | |
1087 | |
| … | |
… | |
| 902 | Sets a feeder/generator on this group: every group can have an |
1187 | Sets a feeder/generator on this group: every group can have an |
| 903 | attached generator that generates requests if idle. The idea behind |
1188 | attached generator that generates requests if idle. The idea behind |
| 904 | this is that, although you could just queue as many requests as you |
1189 | this is that, although you could just queue as many requests as you |
| 905 | want in a group, this might starve other requests for a potentially |
1190 | want in a group, this might starve other requests for a potentially |
| 906 | long time. For example, "aio_scandir" might generate hundreds of |
1191 | long time. For example, "aio_scandir" might generate hundreds of |
| 907 | thousands "aio_stat" requests, delaying any later requests for a |
1192 | thousands of "aio_stat" requests, delaying any later requests for a |
| 908 | long time. |
1193 | long time. |
| 909 | |
1194 | |
| 910 | To avoid this, and allow incremental generation of requests, you can |
1195 | To avoid this, and allow incremental generation of requests, you can |
| 911 | instead a group and set a feeder on it that generates those |
1196 | instead a group and set a feeder on it that generates those |
| 912 | requests. The feed callback will be called whenever there are few |
1197 | requests. The feed callback will be called whenever there are few |
| … | |
… | |
| 955 | |
1240 | |
| 956 | See "poll_cb" for an example. |
1241 | See "poll_cb" for an example. |
| 957 | |
1242 | |
| 958 | IO::AIO::poll_cb |
1243 | IO::AIO::poll_cb |
| 959 | Process some outstanding events on the result pipe. You have to call |
1244 | Process some outstanding events on the result pipe. You have to call |
| 960 | this regularly. Returns 0 if all events could be processed, or -1 if |
1245 | this regularly. Returns 0 if all events could be processed (or there |
| 961 | it returned earlier for whatever reason. Returns immediately when no |
1246 | were no events to process), or -1 if it returned earlier for |
| 962 | events are outstanding. The amount of events processed depends on |
1247 | whatever reason. Returns immediately when no events are outstanding. |
| 963 | the settings of "IO::AIO::max_poll_req" and |
1248 | The amount of events processed depends on the settings of |
| 964 | "IO::AIO::max_poll_time". |
1249 | "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". |
| 965 | |
1250 | |
| 966 | If not all requests were processed for whatever reason, the |
1251 | If not all requests were processed for whatever reason, the |
| 967 | filehandle will still be ready when "poll_cb" returns, so normally |
1252 | filehandle will still be ready when "poll_cb" returns, so normally |
| 968 | you don't have to do anything special to have it called later. |
1253 | you don't have to do anything special to have it called later. |
|
|
1254 | |
|
|
1255 | Apart from calling "IO::AIO::poll_cb" when the event filehandle |
|
|
1256 | becomes ready, it can be beneficial to call this function from loops |
|
|
1257 | which submit a lot of requests, to make sure the results get |
|
|
1258 | processed when they become available and not just when the loop is |
|
|
1259 | finished and the event loop takes over again. This function returns |
|
|
1260 | very fast when there are no outstanding requests. |
| 969 | |
1261 | |
| 970 | Example: Install an Event watcher that automatically calls |
1262 | Example: Install an Event watcher that automatically calls |
| 971 | IO::AIO::poll_cb with high priority (more examples can be found in |
1263 | IO::AIO::poll_cb with high priority (more examples can be found in |
| 972 | the SYNOPSIS section, at the top of this document): |
1264 | the SYNOPSIS section, at the top of this document): |
| 973 | |
1265 | |
| … | |
… | |
| 1067 | |
1359 | |
| 1068 | Under normal circumstances you don't need to call this function. |
1360 | Under normal circumstances you don't need to call this function. |
| 1069 | |
1361 | |
| 1070 | IO::AIO::max_idle $nthreads |
1362 | IO::AIO::max_idle $nthreads |
| 1071 | Limit the number of threads (default: 4) that are allowed to idle |
1363 | Limit the number of threads (default: 4) that are allowed to idle |
| 1072 | (i.e., threads that did not get a request to process within 10 |
1364 | (i.e., threads that did not get a request to process within the idle |
| 1073 | seconds). That means if a thread becomes idle while $nthreads other |
1365 | timeout (default: 10 seconds). That means if a thread becomes idle |
| 1074 | threads are also idle, it will free its resources and exit. |
1366 | while $nthreads other threads are also idle, it will free its |
|
|
1367 | resources and exit. |
| 1075 | |
1368 | |
| 1076 | This is useful when you allow a large number of threads (e.g. 100 or |
1369 | This is useful when you allow a large number of threads (e.g. 100 or |
| 1077 | 1000) to allow for extremely high load situations, but want to free |
1370 | 1000) to allow for extremely high load situations, but want to free |
| 1078 | resources under normal circumstances (1000 threads can easily |
1371 | resources under normal circumstances (1000 threads can easily |
| 1079 | consume 30MB of RAM). |
1372 | consume 30MB of RAM). |
| 1080 | |
1373 | |
| 1081 | The default is probably ok in most situations, especially if thread |
1374 | The default is probably ok in most situations, especially if thread |
| 1082 | creation is fast. If thread creation is very slow on your system you |
1375 | creation is fast. If thread creation is very slow on your system you |
| 1083 | might want to use larger values. |
1376 | might want to use larger values. |
| 1084 | |
1377 | |
|
|
1378 | IO::AIO::idle_timeout $seconds |
|
|
1379 | Sets the minimum idle timeout (default 10) after which worker |
|
|
1380 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
|
|
1381 | |
| 1085 | IO::AIO::max_outstanding $maxreqs |
1382 | IO::AIO::max_outstanding $maxreqs |
|
|
1383 | Sets the maximum number of outstanding requests to $nreqs. If you do |
|
|
1384 | queue up more than this number of requests, the next call to |
|
|
1385 | "IO::AIO::poll_cb" (and other functions calling "poll_cb", such as |
|
|
1386 | "IO::AIO::flush" or "IO::AIO::poll") will block until the limit is |
|
|
1387 | no longer exceeded. |
|
|
1388 | |
|
|
1389 | In other words, this setting does not enforce a queue limit, but can |
|
|
1390 | be used to make poll functions block if the limit is exceeded. |
|
|
1391 | |
| 1086 | This is a very bad function to use in interactive programs because |
1392 | This is a very bad function to use in interactive programs because |
| 1087 | it blocks, and a bad way to reduce concurrency because it is |
1393 | it blocks, and a bad way to reduce concurrency because it is |
| 1088 | inexact: Better use an "aio_group" together with a feed callback. |
1394 | inexact: Better use an "aio_group" together with a feed callback. |
| 1089 | |
1395 | |
| 1090 | Sets the maximum number of outstanding requests to $nreqs. If you do |
1396 | It's main use is in scripts without an event loop - when you want to |
| 1091 | queue up more than this number of requests, the next call to the |
1397 | stat a lot of files, you can write somehting like this: |
| 1092 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
|
|
| 1093 | function will block until the limit is no longer exceeded. |
|
|
| 1094 | |
1398 | |
| 1095 | The default value is very large, so there is no practical limit on |
1399 | IO::AIO::max_outstanding 32; |
|
|
1400 | |
|
|
1401 | for my $path (...) { |
|
|
1402 | aio_stat $path , ...; |
|
|
1403 | IO::AIO::poll_cb; |
|
|
1404 | } |
|
|
1405 | |
|
|
1406 | IO::AIO::flush; |
|
|
1407 | |
|
|
1408 | The call to "poll_cb" inside the loop will normally return |
|
|
1409 | instantly, but as soon as more thna 32 reqeusts are in-flight, it |
|
|
1410 | will block until some requests have been handled. This keeps the |
|
|
1411 | loop from pushing a large number of "aio_stat" requests onto the |
|
|
1412 | queue. |
|
|
1413 | |
|
|
1414 | The default value for "max_outstanding" is very large, so there is |
| 1096 | the number of outstanding requests. |
1415 | no practical limit on the number of outstanding requests. |
| 1097 | |
|
|
| 1098 | You can still queue as many requests as you want. Therefore, |
|
|
| 1099 | "max_outstanding" is mainly useful in simple scripts (with low |
|
|
| 1100 | values) or as a stop gap to shield against fatal memory overflow |
|
|
| 1101 | (with large values). |
|
|
| 1102 | |
1416 | |
| 1103 | STATISTICAL INFORMATION |
1417 | STATISTICAL INFORMATION |
| 1104 | IO::AIO::nreqs |
1418 | IO::AIO::nreqs |
| 1105 | Returns the number of requests currently in the ready, execute or |
1419 | Returns the number of requests currently in the ready, execute or |
| 1106 | pending states (i.e. for which their callback has not been invoked |
1420 | pending states (i.e. for which their callback has not been invoked |
| … | |
… | |
| 1130 | set to non-blocking operations). |
1444 | set to non-blocking operations). |
| 1131 | |
1445 | |
| 1132 | Returns the number of bytes copied, or -1 on error. |
1446 | Returns the number of bytes copied, or -1 on error. |
| 1133 | |
1447 | |
| 1134 | IO::AIO::fadvise $fh, $offset, $len, $advice |
1448 | IO::AIO::fadvise $fh, $offset, $len, $advice |
| 1135 | Simply calls the "posix_fadvise" function (see it's manpage for |
1449 | Simply calls the "posix_fadvise" function (see its manpage for |
| 1136 | details). The following advice constants are avaiable: |
1450 | details). The following advice constants are available: |
| 1137 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
1451 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
| 1138 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
1452 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
| 1139 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
1453 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
| 1140 | |
1454 | |
| 1141 | On systems that do not implement "posix_fadvise", this function |
1455 | On systems that do not implement "posix_fadvise", this function |
| 1142 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
1456 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
|
|
1457 | |
|
|
1458 | IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1459 | Simply calls the "posix_madvise" function (see its manpage for |
|
|
1460 | details). The following advice constants are available: |
|
|
1461 | "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", |
|
|
1462 | "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", |
|
|
1463 | "IO::AIO::MADV_DONTNEED". |
|
|
1464 | |
|
|
1465 | On systems that do not implement "posix_madvise", this function |
|
|
1466 | returns ENOSYS, otherwise the return value of "posix_madvise". |
|
|
1467 | |
|
|
1468 | IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1469 | Simply calls the "mprotect" function on the preferably AIO::mmap'ed |
|
|
1470 | $scalar (see its manpage for details). The following protect |
|
|
1471 | constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", |
|
|
1472 | "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". |
|
|
1473 | |
|
|
1474 | On systems that do not implement "mprotect", this function returns |
|
|
1475 | ENOSYS, otherwise the return value of "mprotect". |
| 1143 | |
1476 | |
| 1144 | IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
1477 | IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
| 1145 | Memory-maps a file (or anonymous memory range) and attaches it to |
1478 | Memory-maps a file (or anonymous memory range) and attaches it to |
| 1146 | the given $scalar, which will act like a string scalar. |
1479 | the given $scalar, which will act like a string scalar. |
| 1147 | |
1480 | |
| … | |
… | |
| 1192 | my $fast_md5 = md5 $data; |
1525 | my $fast_md5 = md5 $data; |
| 1193 | |
1526 | |
| 1194 | IO::AIO::munmap $scalar |
1527 | IO::AIO::munmap $scalar |
| 1195 | Removes a previous mmap and undefines the $scalar. |
1528 | Removes a previous mmap and undefines the $scalar. |
| 1196 | |
1529 | |
| 1197 | IO::AIO::mlockall $flags |
1530 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
| 1198 | Calls the "mlockall" function with the given $flags (a combination |
1531 | Calls the "munlock" function, undoing the effects of a previous |
| 1199 | of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL__FUTURE"). |
1532 | "aio_mlock" call (see its description for details). |
| 1200 | |
|
|
| 1201 | On systems that do not implement "mlockall", this function returns |
|
|
| 1202 | ENOSYS, otherwise the return value of "mlockall". |
|
|
| 1203 | |
1533 | |
| 1204 | IO::AIO::munlockall |
1534 | IO::AIO::munlockall |
| 1205 | Calls the "munlockall" function. |
1535 | Calls the "munlockall" function. |
| 1206 | |
1536 | |
| 1207 | On systems that do not implement "munlockall", this function returns |
1537 | On systems that do not implement "munlockall", this function returns |
| 1208 | ENOSYS, otherwise the return value of "munlockall". |
1538 | ENOSYS, otherwise the return value of "munlockall". |
|
|
1539 | |
|
|
1540 | IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags |
|
|
1541 | Calls the GNU/Linux splice(2) syscall, if available. If $r_off or |
|
|
1542 | $w_off are "undef", then "NULL" is passed for these, otherwise they |
|
|
1543 | should be the file offset. |
|
|
1544 | |
|
|
1545 | The following symbol flag values are available: |
|
|
1546 | "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK", |
|
|
1547 | "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT". |
|
|
1548 | |
|
|
1549 | See the splice(2) manpage for details. |
|
|
1550 | |
|
|
1551 | IO::AIO::tee $r_fh, $w_fh, $length, $flags |
|
|
1552 | Calls the GNU/Linux tee(2) syscall, see it's manpage and the |
|
|
1553 | description for "IO::AIO::splice" above for details. |
| 1209 | |
1554 | |
| 1210 | EVENT LOOP INTEGRATION |
1555 | EVENT LOOP INTEGRATION |
| 1211 | It is recommended to use AnyEvent::AIO to integrate IO::AIO |
1556 | It is recommended to use AnyEvent::AIO to integrate IO::AIO |
| 1212 | automatically into many event loops: |
1557 | automatically into many event loops: |
| 1213 | |
1558 | |
| … | |
… | |
| 1236 | # Danga::Socket integration |
1581 | # Danga::Socket integration |
| 1237 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
1582 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
| 1238 | \&IO::AIO::poll_cb); |
1583 | \&IO::AIO::poll_cb); |
| 1239 | |
1584 | |
| 1240 | FORK BEHAVIOUR |
1585 | FORK BEHAVIOUR |
| 1241 | This module should do "the right thing" when the process using it forks: |
1586 | Usage of pthreads in a program changes the semantics of fork |
|
|
1587 | considerably. Specifically, only async-safe functions can be called |
|
|
1588 | after fork. Perl doesn't know about this, so in general, you cannot call |
|
|
1589 | fork with defined behaviour in perl if pthreads are involved. IO::AIO |
|
|
1590 | uses pthreads, so this applies, but many other extensions and (for |
|
|
1591 | inexplicable reasons) perl itself often is linked against pthreads, so |
|
|
1592 | this limitation applies to quite a lot of perls. |
| 1242 | |
1593 | |
| 1243 | Before the fork, IO::AIO enters a quiescent state where no requests can |
1594 | This module no longer tries to fight your OS, or POSIX. That means |
| 1244 | be added in other threads and no results will be processed. After the |
1595 | IO::AIO only works in the process that loaded it. Forking is fully |
| 1245 | fork the parent simply leaves the quiescent state and continues |
1596 | supported, but using IO::AIO in the child is not. |
| 1246 | request/result processing, while the child frees the request/result |
|
|
| 1247 | queue (so that the requests started before the fork will only be handled |
|
|
| 1248 | in the parent). Threads will be started on demand until the limit set in |
|
|
| 1249 | the parent process has been reached again. |
|
|
| 1250 | |
1597 | |
| 1251 | In short: the parent will, after a short pause, continue as if fork had |
1598 | You might get around by not *using* IO::AIO before (or after) forking. |
| 1252 | not been called, while the child will act as if IO::AIO has not been |
1599 | You could also try to call the IO::AIO::reinit function in the child: |
| 1253 | used yet. |
1600 | |
|
|
1601 | IO::AIO::reinit |
|
|
1602 | Abandons all current requests and I/O threads and simply |
|
|
1603 | reinitialises all data structures. This is not an operation |
|
|
1604 | supported by any standards, but happens to work on GNU/Linux and |
|
|
1605 | some newer BSD systems. |
|
|
1606 | |
|
|
1607 | The only reasonable use for this function is to call it after |
|
|
1608 | forking, if "IO::AIO" was used in the parent. Calling it while |
|
|
1609 | IO::AIO is active in the process will result in undefined behaviour. |
|
|
1610 | Calling it at any time will also result in any undefined (by POSIX) |
|
|
1611 | behaviour. |
| 1254 | |
1612 | |
| 1255 | MEMORY USAGE |
1613 | MEMORY USAGE |
| 1256 | Per-request usage: |
1614 | Per-request usage: |
| 1257 | |
1615 | |
| 1258 | Each aio request uses - depending on your architecture - around 100-200 |
1616 | Each aio request uses - depending on your architecture - around 100-200 |
