… | |
… | |
62 | etc.), but can also be used to easily do operations in parallel that are |
62 | etc.), but can also be used to easily do operations in parallel that are |
63 | normally done sequentially, e.g. stat'ing many files, which is much faster |
63 | normally done sequentially, e.g. stat'ing many files, which is much faster |
64 | on a RAID volume or over NFS when you do a number of stat operations |
64 | on a RAID volume or over NFS when you do a number of stat operations |
65 | concurrently. |
65 | concurrently. |
66 | |
66 | |
67 | While most of this works on all types of file descriptors (for example |
67 | While most of this works on all types of file descriptors (for |
68 | sockets), using these functions on file descriptors that support |
68 | example sockets), using these functions on file descriptors that |
69 | nonblocking operation (again, sockets, pipes etc.) is very inefficient or |
69 | support nonblocking operation (again, sockets, pipes etc.) is very |
70 | might not work (aio_read fails on sockets/pipes/fifos). Use an event loop |
70 | inefficient. Use an event loop for that (such as the L<Event|Event> |
71 | for that (such as the L<Event|Event> module): IO::AIO will naturally fit |
71 | module): IO::AIO will naturally fit into such an event loop itself. |
72 | into such an event loop itself. |
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|
73 | |
72 | |
74 | In this version, a number of threads are started that execute your |
73 | In this version, a number of threads are started that execute your |
75 | requests and signal their completion. You don't need thread support |
74 | requests and signal their completion. You don't need thread support |
76 | in perl, and the threads created by this module will not be visible |
75 | in perl, and the threads created by this module will not be visible |
77 | to perl. In the future, this module might make use of the native aio |
76 | to perl. In the future, this module might make use of the native aio |
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79 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
78 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
80 | files currently, for example), and they would only support aio_read and |
79 | files currently, for example), and they would only support aio_read and |
81 | aio_write, so the remaining functionality would have to be implemented |
80 | aio_write, so the remaining functionality would have to be implemented |
82 | using threads anyway. |
81 | using threads anyway. |
83 | |
82 | |
84 | Although the module will work with in the presence of other (Perl-) |
83 | Although the module will work in the presence of other (Perl-) threads, |
85 | threads, it is currently not reentrant in any way, so use appropriate |
84 | it is currently not reentrant in any way, so use appropriate locking |
86 | locking yourself, always call C<poll_cb> from within the same thread, or |
85 | yourself, always call C<poll_cb> from within the same thread, or never |
87 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
86 | call C<poll_cb> (or other C<aio_> functions) recursively. |
88 | |
87 | |
89 | =head2 EXAMPLE |
88 | =head2 EXAMPLE |
90 | |
89 | |
91 | This is a simple example that uses the Event module and loads |
90 | This is a simple example that uses the Event module and loads |
92 | F</etc/passwd> asynchronously: |
91 | F</etc/passwd> asynchronously: |
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196 | |
195 | |
197 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
196 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
198 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
197 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
199 | aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link |
198 | aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link |
200 | aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir |
199 | aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir |
201 | aio_chown aio_chmod aio_utime); |
200 | aio_chown aio_chmod aio_utime aio_truncate); |
202 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); |
201 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); |
203 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
202 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
204 | min_parallel max_parallel max_idle |
203 | min_parallel max_parallel max_idle |
205 | nreqs nready npending nthreads |
204 | nreqs nready npending nthreads |
206 | max_poll_time max_poll_reqs); |
205 | max_poll_time max_poll_reqs); |
… | |
… | |
325 | |
324 | |
326 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
325 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
327 | |
326 | |
328 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
327 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
329 | |
328 | |
330 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
329 | Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> |
331 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
330 | into the scalar given by C<$data> and offset C<$dataoffset> and calls the |
332 | callback without the actual number of bytes read (or -1 on error, just |
331 | callback without the actual number of bytes read (or -1 on error, just |
333 | like the syscall). |
332 | like the syscall). |
334 | |
333 | |
|
|
334 | If C<$offset> is undefined, then the current file offset will be used (and |
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|
335 | updated), otherwise the file offset will not be changed by these calls. |
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|
336 | |
|
|
337 | If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. |
|
|
338 | |
|
|
339 | If C<$dataoffset> is less than zero, it will be counted from the end of |
|
|
340 | C<$data>. |
|
|
341 | |
335 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
342 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
336 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
343 | is outstanding. Modifying it can result in segfaults or World War III (if |
337 | necessary/optional hardware is installed). |
344 | the necessary/optional hardware is installed). |
338 | |
345 | |
339 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
346 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
340 | offset C<0> within the scalar: |
347 | offset C<0> within the scalar: |
341 | |
348 | |
342 | aio_read $fh, 7, 15, $buffer, 0, sub { |
349 | aio_read $fh, 7, 15, $buffer, 0, sub { |
… | |
… | |
417 | utime(2). If called on a file descriptor, uses futimes(2) if available, |
424 | utime(2). If called on a file descriptor, uses futimes(2) if available, |
418 | otherwise returns ENOSYS, so this is not portable. |
425 | otherwise returns ENOSYS, so this is not portable. |
419 | |
426 | |
420 | Examples: |
427 | Examples: |
421 | |
428 | |
422 | # set atime and mtime to current time: |
429 | # set atime and mtime to current time (basically touch(1)): |
423 | aio_utime "path", undef, undef; |
430 | aio_utime "path", undef, undef; |
424 | # set atime to current time and mtime to beginning of the epoch: |
431 | # set atime to current time and mtime to beginning of the epoch: |
425 | aio_utime "path", time, undef; # undef==0 |
432 | aio_utime "path", time, undef; # undef==0 |
426 | |
433 | |
427 | |
434 | |
… | |
… | |
434 | |
441 | |
435 | # same as "chown root path" in the shell: |
442 | # same as "chown root path" in the shell: |
436 | aio_chown "path", 0, -1; |
443 | aio_chown "path", 0, -1; |
437 | # same as above: |
444 | # same as above: |
438 | aio_chown "path", 0, undef; |
445 | aio_chown "path", 0, undef; |
|
|
446 | |
|
|
447 | |
|
|
448 | =item aio_truncate $fh_or_path, $offset, $callback->($status) |
|
|
449 | |
|
|
450 | Works like truncate(2) or ftruncate(2). |
439 | |
451 | |
440 | |
452 | |
441 | =item aio_chmod $fh_or_path, $mode, $callback->($status) |
453 | =item aio_chmod $fh_or_path, $mode, $callback->($status) |
442 | |
454 | |
443 | Works like perl's C<chmod> function. |
455 | Works like perl's C<chmod> function. |
… | |
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1283 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
1295 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
1284 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
1296 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
1285 | scalars and other data passed into aio requests will also be locked and |
1297 | scalars and other data passed into aio requests will also be locked and |
1286 | will consume memory till the request has entered the done state. |
1298 | will consume memory till the request has entered the done state. |
1287 | |
1299 | |
1288 | This is now awfully much, so queuing lots of requests is not usually a |
1300 | This is not awfully much, so queuing lots of requests is not usually a |
1289 | problem. |
1301 | problem. |
1290 | |
1302 | |
1291 | Per-thread usage: |
1303 | Per-thread usage: |
1292 | |
1304 | |
1293 | In the execution phase, some aio requests require more memory for |
1305 | In the execution phase, some aio requests require more memory for |