… | |
… | |
24 | $req->cancel; # cancel request if still in queue |
24 | $req->cancel; # cancel request if still in queue |
25 | |
25 | |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
26 | my $grp = aio_group sub { print "all stats done\n" }; |
27 | add $grp aio_stat "..." for ...; |
27 | add $grp aio_stat "..." for ...; |
28 | |
28 | |
|
|
29 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
30 | use AnyEvent::AIO; |
|
|
31 | |
29 | # AnyEvent integration |
32 | # EV integration |
30 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
33 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
31 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
|
|
32 | |
34 | |
33 | # Event integration |
35 | # Event integration |
34 | Event->io (fd => IO::AIO::poll_fileno, |
36 | Event->io (fd => IO::AIO::poll_fileno, |
35 | poll => 'r', |
37 | poll => 'r', |
36 | cb => \&IO::AIO::poll_cb); |
38 | cb => \&IO::AIO::poll_cb); |
… | |
… | |
47 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
49 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
48 | \&IO::AIO::poll_cb); |
50 | \&IO::AIO::poll_cb); |
49 | |
51 | |
50 | DESCRIPTION |
52 | DESCRIPTION |
51 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
52 | operating system supports. |
54 | operating system supports. It is implemented as an interface to "libeio" |
|
|
55 | (<http://software.schmorp.de/pkg/libeio.html>). |
53 | |
56 | |
54 | Asynchronous means that operations that can normally block your program |
57 | Asynchronous means that operations that can normally block your program |
55 | (e.g. reading from disk) will be done asynchronously: the operation will |
58 | (e.g. reading from disk) will be done asynchronously: the operation will |
56 | still block, but you can do something else in the meantime. This is |
59 | still block, but you can do something else in the meantime. This is |
57 | extremely useful for programs that need to stay interactive even when |
60 | extremely useful for programs that need to stay interactive even when |
… | |
… | |
62 | operations concurrently. |
65 | operations concurrently. |
63 | |
66 | |
64 | 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 example |
65 | sockets), using these functions on file descriptors that support |
68 | sockets), using these functions on file descriptors that support |
66 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
69 | nonblocking operation (again, sockets, pipes etc.) is very inefficient. |
67 | Use an event loop for that (such as the Event module): IO::AIO will |
70 | Use an event loop for that (such as the EV module): IO::AIO will |
68 | naturally fit into such an event loop itself. |
71 | naturally fit into such an event loop itself. |
69 | |
72 | |
70 | 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 |
71 | requests and signal their completion. You don't need thread support in |
74 | requests and signal their completion. You don't need thread support in |
72 | perl, and the threads created by this module will not be visible to |
75 | perl, and the threads created by this module will not be visible to |
… | |
… | |
81 | it is currently not reentrant in any way, so use appropriate locking |
84 | it is currently not reentrant in any way, so use appropriate locking |
82 | yourself, always call "poll_cb" from within the same thread, or never |
85 | yourself, always call "poll_cb" from within the same thread, or never |
83 | call "poll_cb" (or other "aio_" functions) recursively. |
86 | call "poll_cb" (or other "aio_" functions) recursively. |
84 | |
87 | |
85 | EXAMPLE |
88 | EXAMPLE |
86 | This is a simple example that uses the Event module and loads |
89 | This is a simple example that uses the EV module and loads /etc/passwd |
87 | /etc/passwd asynchronously: |
90 | asynchronously: |
88 | |
91 | |
89 | use Fcntl; |
92 | use Fcntl; |
90 | use Event; |
93 | use EV; |
91 | use IO::AIO; |
94 | use IO::AIO; |
92 | |
95 | |
93 | # register the IO::AIO callback with Event |
96 | # register the IO::AIO callback with EV |
94 | Event->io (fd => IO::AIO::poll_fileno, |
97 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
95 | poll => 'r', |
|
|
96 | cb => \&IO::AIO::poll_cb); |
|
|
97 | |
98 | |
98 | # queue the request to open /etc/passwd |
99 | # queue the request to open /etc/passwd |
99 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
100 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
100 | my $fh = shift |
101 | my $fh = shift |
101 | or die "error while opening: $!"; |
102 | or die "error while opening: $!"; |
… | |
… | |
113 | |
114 | |
114 | # file contents now in $contents |
115 | # file contents now in $contents |
115 | print $contents; |
116 | print $contents; |
116 | |
117 | |
117 | # exit event loop and program |
118 | # exit event loop and program |
118 | Event::unloop; |
119 | EV::unloop; |
119 | }; |
120 | }; |
120 | }; |
121 | }; |
121 | |
122 | |
122 | # possibly queue up other requests, or open GUI windows, |
123 | # possibly queue up other requests, or open GUI windows, |
123 | # check for sockets etc. etc. |
124 | # check for sockets etc. etc. |
124 | |
125 | |
125 | # process events as long as there are some: |
126 | # process events as long as there are some: |
126 | Event::loop; |
127 | EV::loop; |
127 | |
128 | |
128 | REQUEST ANATOMY AND LIFETIME |
129 | REQUEST ANATOMY AND LIFETIME |
129 | Every "aio_*" function creates a request. which is a C data structure |
130 | Every "aio_*" function creates a request. which is a C data structure |
130 | not directly visible to Perl. |
131 | not directly visible to Perl. |
131 | |
132 | |
… | |
… | |
173 | All the "aio_*" calls are more or less thin wrappers around the syscall |
174 | All the "aio_*" calls are more or less thin wrappers around the syscall |
174 | with the same name (sans "aio_"). The arguments are similar or |
175 | with the same name (sans "aio_"). The arguments are similar or |
175 | identical, and they all accept an additional (and optional) $callback |
176 | identical, and they all accept an additional (and optional) $callback |
176 | argument which must be a code reference. This code reference will get |
177 | argument which must be a code reference. This code reference will get |
177 | called with the syscall return code (e.g. most syscalls return -1 on |
178 | called with the syscall return code (e.g. most syscalls return -1 on |
178 | error, unlike perl, which usually delivers "false") as it's sole |
179 | error, unlike perl, which usually delivers "false") as its sole argument |
179 | argument when the given syscall has been executed asynchronously. |
180 | after the given syscall has been executed asynchronously. |
180 | |
181 | |
181 | All functions expecting a filehandle keep a copy of the filehandle |
182 | All functions expecting a filehandle keep a copy of the filehandle |
182 | internally until the request has finished. |
183 | internally until the request has finished. |
183 | |
184 | |
184 | All functions return request objects of type IO::AIO::REQ that allow |
185 | All functions return request objects of type IO::AIO::REQ that allow |
… | |
… | |
197 | the user environment, d) use Glib::filename_from_unicode on unicode |
198 | the user environment, d) use Glib::filename_from_unicode on unicode |
198 | filenames or e) use something else to ensure your scalar has the correct |
199 | filenames or e) use something else to ensure your scalar has the correct |
199 | contents. |
200 | contents. |
200 | |
201 | |
201 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
202 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
202 | handles correctly wether it is set or not. |
203 | handles correctly whether it is set or not. |
203 | |
204 | |
204 | $prev_pri = aioreq_pri [$pri] |
205 | $prev_pri = aioreq_pri [$pri] |
205 | Returns the priority value that would be used for the next request |
206 | Returns the priority value that would be used for the next request |
206 | and, if $pri is given, sets the priority for the next aio request. |
207 | and, if $pri is given, sets the priority for the next aio request. |
207 | |
208 | |
… | |
… | |
262 | Asynchronously close a file and call the callback with the result |
263 | Asynchronously close a file and call the callback with the result |
263 | code. |
264 | code. |
264 | |
265 | |
265 | Unfortunately, you can't do this to perl. Perl *insists* very |
266 | Unfortunately, you can't do this to perl. Perl *insists* very |
266 | strongly on closing the file descriptor associated with the |
267 | strongly on closing the file descriptor associated with the |
267 | filehandle itself. Here is what aio_close will try: |
268 | filehandle itself. |
268 | |
269 | |
269 | 1. dup()licate the fd |
270 | Therefore, "aio_close" will not close the filehandle - instead it |
270 | 2. asynchronously close() the duplicated fd |
271 | will use dup2 to overwrite the file descriptor with the write-end of |
271 | 3. dup()licate the fd once more |
272 | a pipe (the pipe fd will be created on demand and will be cached). |
272 | 4. let perl close() the filehandle |
|
|
273 | 5. asynchronously close the duplicated fd |
|
|
274 | |
273 | |
275 | The idea is that the first close() flushes stuff to disk that |
274 | Or in other words: the file descriptor will be closed, but it will |
276 | closing an fd will flush, so when perl closes the fd, nothing much |
275 | not be free for reuse until the perl filehandle is closed. |
277 | will need to be flushed. The second async. close() will then flush |
|
|
278 | stuff to disk that closing the last fd to the file will flush. |
|
|
279 | |
|
|
280 | Just FYI, SuSv3 has this to say on close: |
|
|
281 | |
|
|
282 | All outstanding record locks owned by the process on the file |
|
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283 | associated with the file descriptor shall be removed. |
|
|
284 | |
|
|
285 | If fildes refers to a socket, close() shall cause the socket to be |
|
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286 | destroyed. ... close() shall block for up to the current linger |
|
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287 | interval until all data is transmitted. |
|
|
288 | [this actually sounds like a specification bug, but who knows] |
|
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289 | |
|
|
290 | And at least Linux additionally actually flushes stuff on every |
|
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291 | close, even when the file itself is still open. |
|
|
292 | |
|
|
293 | Sounds enourmously inefficient and complicated? Yes... please show |
|
|
294 | me how to nuke perl's fd out of existence... |
|
|
295 | |
276 | |
296 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
277 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
297 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
278 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
298 | Reads or writes $length bytes from the specified $fh and $offset |
279 | Reads or writes $length bytes from or to the specified $fh and |
299 | into the scalar given by $data and offset $dataoffset and calls the |
280 | $offset into the scalar given by $data and offset $dataoffset and |
300 | callback without the actual number of bytes read (or -1 on error, |
281 | calls the callback without the actual number of bytes read (or -1 on |
301 | just like the syscall). |
282 | error, just like the syscall). |
|
|
283 | |
|
|
284 | "aio_read" will, like "sysread", shrink or grow the $data scalar to |
|
|
285 | offset plus the actual number of bytes read. |
302 | |
286 | |
303 | If $offset is undefined, then the current file descriptor offset |
287 | If $offset is undefined, then the current file descriptor offset |
304 | will be used (and updated), otherwise the file descriptor offset |
288 | will be used (and updated), otherwise the file descriptor offset |
305 | will not be changed by these calls. |
289 | will not be changed by these calls. |
306 | |
290 | |
… | |
… | |
457 | aio_readdir $pathname, $callback->($entries) |
441 | aio_readdir $pathname, $callback->($entries) |
458 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
442 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
459 | entire directory (i.e. opendir + readdir + closedir). The entries |
443 | entire directory (i.e. opendir + readdir + closedir). The entries |
460 | will not be sorted, and will NOT include the "." and ".." entries. |
444 | will not be sorted, and will NOT include the "." and ".." entries. |
461 | |
445 | |
462 | The callback a single argument which is either "undef" or an |
446 | The callback is passed a single argument which is either "undef" or |
463 | array-ref with the filenames. |
447 | an array-ref with the filenames. |
|
|
448 | |
|
|
449 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
450 | Quite similar to "aio_readdir", but the $flags argument allows to |
|
|
451 | tune behaviour and output format. In case of an error, $entries will |
|
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452 | be "undef". |
|
|
453 | |
|
|
454 | The flags are a combination of the following constants, ORed |
|
|
455 | together (the flags will also be passed to the callback, possibly |
|
|
456 | modified): |
|
|
457 | |
|
|
458 | IO::AIO::READDIR_DENTS |
|
|
459 | When this flag is off, then the callback gets an arrayref with |
|
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460 | of names only (as with "aio_readdir"), otherwise it gets an |
|
|
461 | arrayref with "[$name, $type, $inode]" arrayrefs, each |
|
|
462 | describing a single directory entry in more detail. |
|
|
463 | |
|
|
464 | $name is the name of the entry. |
|
|
465 | |
|
|
466 | $type is one of the "IO::AIO::DT_xxx" constants: |
|
|
467 | |
|
|
468 | "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", |
|
|
469 | "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", |
|
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470 | "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". |
|
|
471 | |
|
|
472 | "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If |
|
|
473 | you need to know, you have to run stat yourself. Also, for speed |
|
|
474 | reasons, the $type scalars are read-only: you can not modify |
|
|
475 | them. |
|
|
476 | |
|
|
477 | $inode is the inode number (which might not be exact on systems |
|
|
478 | with 64 bit inode numbers and 32 bit perls). This field has |
|
|
479 | unspecified content on systems that do not deliver the inode |
|
|
480 | information. |
|
|
481 | |
|
|
482 | IO::AIO::READDIR_DIRS_FIRST |
|
|
483 | When this flag is set, then the names will be returned in an |
|
|
484 | order where likely directories come first. This is useful when |
|
|
485 | you need to quickly find directories, or you want to find all |
|
|
486 | directories while avoiding to stat() each entry. |
|
|
487 | |
|
|
488 | If the system returns type information in readdir, then this is |
|
|
489 | used to find directories directly. Otherwise, likely directories |
|
|
490 | are files beginning with ".", or otherwise files with no dots, |
|
|
491 | of which files with short names are tried first. |
|
|
492 | |
|
|
493 | IO::AIO::READDIR_STAT_ORDER |
|
|
494 | When this flag is set, then the names will be returned in an |
|
|
495 | order suitable for stat()'ing each one. That is, when you plan |
|
|
496 | to stat() all files in the given directory, then the returned |
|
|
497 | order will likely be fastest. |
|
|
498 | |
|
|
499 | If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are |
|
|
500 | specified, then the likely dirs come first, resulting in a less |
|
|
501 | optimal stat order. |
|
|
502 | |
|
|
503 | IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
504 | This flag should not be set when calling "aio_readdirx". |
|
|
505 | Instead, it is being set by "aio_readdirx", when any of the |
|
|
506 | $type's found were "IO::AIO::DT_UNKNOWN". The absense of this |
|
|
507 | flag therefore indicates that all $type's are known, which can |
|
|
508 | be used to speed up some algorithms. |
464 | |
509 | |
465 | aio_load $path, $data, $callback->($status) |
510 | aio_load $path, $data, $callback->($status) |
466 | This is a composite request that tries to fully load the given file |
511 | This is a composite request that tries to fully load the given file |
467 | into memory. Status is the same as with aio_read. |
512 | into memory. Status is the same as with aio_read. |
468 | |
513 | |
469 | aio_copy $srcpath, $dstpath, $callback->($status) |
514 | aio_copy $srcpath, $dstpath, $callback->($status) |
470 | Try to copy the *file* (directories not supported as either source |
515 | Try to copy the *file* (directories not supported as either source |
471 | or destination) from $srcpath to $dstpath and call the callback with |
516 | or destination) from $srcpath to $dstpath and call the callback with |
472 | the 0 (error) or -1 ok. |
517 | the 0 (error) or -1 ok. |
473 | |
518 | |
474 | This is a composite request that it creates the destination file |
519 | This is a composite request that creates the destination file with |
475 | with mode 0200 and copies the contents of the source file into it |
520 | mode 0200 and copies the contents of the source file into it using |
476 | using "aio_sendfile", followed by restoring atime, mtime, access |
521 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
477 | mode and uid/gid, in that order. |
522 | uid/gid, in that order. |
478 | |
523 | |
479 | If an error occurs, the partial destination file will be unlinked, |
524 | If an error occurs, the partial destination file will be unlinked, |
480 | if possible, except when setting atime, mtime, access mode and |
525 | if possible, except when setting atime, mtime, access mode and |
481 | uid/gid, where errors are being ignored. |
526 | uid/gid, where errors are being ignored. |
482 | |
527 | |
483 | aio_move $srcpath, $dstpath, $callback->($status) |
528 | aio_move $srcpath, $dstpath, $callback->($status) |
484 | Try to move the *file* (directories not supported as either source |
529 | Try to move the *file* (directories not supported as either source |
485 | or destination) from $srcpath to $dstpath and call the callback with |
530 | or destination) from $srcpath to $dstpath and call the callback with |
486 | the 0 (error) or -1 ok. |
531 | the 0 (error) or -1 ok. |
487 | |
532 | |
488 | This is a composite request that tries to rename(2) the file first. |
533 | This is a composite request that tries to rename(2) the file first; |
489 | If rename files with "EXDEV", it copies the file with "aio_copy" |
534 | if rename fails with "EXDEV", it copies the file with "aio_copy" |
490 | and, if that is successful, unlinking the $srcpath. |
535 | and, if that is successful, unlinks the $srcpath. |
491 | |
536 | |
492 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
537 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
493 | Scans a directory (similar to "aio_readdir") but additionally tries |
538 | Scans a directory (similar to "aio_readdir") but additionally tries |
494 | to efficiently separate the entries of directory $path into two sets |
539 | to efficiently separate the entries of directory $path into two sets |
495 | of names, directories you can recurse into (directories), and ones |
540 | of names, directories you can recurse into (directories), and ones |
… | |
… | |
515 | Implementation notes. |
560 | Implementation notes. |
516 | |
561 | |
517 | The "aio_readdir" cannot be avoided, but "stat()"'ing every entry |
562 | The "aio_readdir" cannot be avoided, but "stat()"'ing every entry |
518 | can. |
563 | can. |
519 | |
564 | |
|
|
565 | If readdir returns file type information, then this is used directly |
|
|
566 | to find directories. |
|
|
567 | |
520 | After reading the directory, the modification time, size etc. of the |
568 | Otherwise, after reading the directory, the modification time, size |
521 | directory before and after the readdir is checked, and if they match |
569 | etc. of the directory before and after the readdir is checked, and |
522 | (and isn't the current time), the link count will be used to decide |
570 | if they match (and isn't the current time), the link count will be |
523 | how many entries are directories (if >= 2). Otherwise, no knowledge |
571 | used to decide how many entries are directories (if >= 2). |
524 | of the number of subdirectories will be assumed. |
572 | Otherwise, no knowledge of the number of subdirectories will be |
|
|
573 | assumed. |
525 | |
574 | |
526 | Then entries will be sorted into likely directories (everything |
575 | Then entries will be sorted into likely directories a non-initial |
527 | without a non-initial dot currently) and likely non-directories |
576 | dot currently) and likely non-directories (see "aio_readdirx"). Then |
528 | (everything else). Then every entry plus an appended "/." will be |
577 | every entry plus an appended "/." will be "stat"'ed, likely |
529 | "stat"'ed, likely directories first. If that succeeds, it assumes |
578 | directories first, in order of their inode numbers. If that |
530 | that the entry is a directory or a symlink to directory (which will |
579 | succeeds, it assumes that the entry is a directory or a symlink to |
531 | be checked seperately). This is often faster than stat'ing the entry |
580 | directory (which will be checked seperately). This is often faster |
532 | itself because filesystems might detect the type of the entry |
581 | than stat'ing the entry itself because filesystems might detect the |
533 | without reading the inode data (e.g. ext2fs filetype feature). |
582 | type of the entry without reading the inode data (e.g. ext2fs |
|
|
583 | filetype feature), even on systems that cannot return the filetype |
|
|
584 | information on readdir. |
534 | |
585 | |
535 | If the known number of directories (link count - 2) has been |
586 | If the known number of directories (link count - 2) has been |
536 | reached, the rest of the entries is assumed to be non-directories. |
587 | reached, the rest of the entries is assumed to be non-directories. |
537 | |
588 | |
538 | This only works with certainty on POSIX (= UNIX) filesystems, which |
589 | This only works with certainty on POSIX (= UNIX) filesystems, which |
… | |
… | |
546 | Delete a directory tree starting (and including) $path, return the |
597 | Delete a directory tree starting (and including) $path, return the |
547 | status of the final "rmdir" only. This is a composite request that |
598 | status of the final "rmdir" only. This is a composite request that |
548 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
599 | uses "aio_scandir" to recurse into and rmdir directories, and unlink |
549 | everything else. |
600 | everything else. |
550 | |
601 | |
|
|
602 | aio_sync $callback->($status) |
|
|
603 | Asynchronously call sync and call the callback when finished. |
|
|
604 | |
551 | aio_fsync $fh, $callback->($status) |
605 | aio_fsync $fh, $callback->($status) |
552 | Asynchronously call fsync on the given filehandle and call the |
606 | Asynchronously call fsync on the given filehandle and call the |
553 | callback with the fsync result code. |
607 | callback with the fsync result code. |
554 | |
608 | |
555 | aio_fdatasync $fh, $callback->($status) |
609 | aio_fdatasync $fh, $callback->($status) |
556 | Asynchronously call fdatasync on the given filehandle and call the |
610 | Asynchronously call fdatasync on the given filehandle and call the |
557 | callback with the fdatasync result code. |
611 | callback with the fdatasync result code. |
558 | |
612 | |
559 | If this call isn't available because your OS lacks it or it couldn't |
613 | If this call isn't available because your OS lacks it or it couldn't |
560 | be detected, it will be emulated by calling "fsync" instead. |
614 | be detected, it will be emulated by calling "fsync" instead. |
|
|
615 | |
|
|
616 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
617 | Sync the data portion of the file specified by $offset and $length |
|
|
618 | to disk (but NOT the metadata), by calling the Linux-specific |
|
|
619 | sync_file_range call. If sync_file_range is not available or it |
|
|
620 | returns ENOSYS, then fdatasync or fsync is being substituted. |
|
|
621 | |
|
|
622 | $flags can be a combination of |
|
|
623 | "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", |
|
|
624 | "IO::AIO::SYNC_FILE_RANGE_WRITE" and |
|
|
625 | "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range |
|
|
626 | manpage for details. |
|
|
627 | |
|
|
628 | aio_pathsync $path, $callback->($status) |
|
|
629 | This request tries to open, fsync and close the given path. This is |
|
|
630 | a composite request intended to sync directories after directory |
|
|
631 | operations (E.g. rename). This might not work on all operating |
|
|
632 | systems or have any specific effect, but usually it makes sure that |
|
|
633 | directory changes get written to disc. It works for anything that |
|
|
634 | can be opened for read-only, not just directories. |
|
|
635 | |
|
|
636 | Passes 0 when everything went ok, and -1 on error. |
561 | |
637 | |
562 | aio_group $callback->(...) |
638 | aio_group $callback->(...) |
563 | This is a very special aio request: Instead of doing something, it |
639 | This is a very special aio request: Instead of doing something, it |
564 | is a container for other aio requests, which is useful if you want |
640 | is a container for other aio requests, which is useful if you want |
565 | to bundle many requests into a single, composite, request with a |
641 | to bundle many requests into a single, composite, request with a |
… | |
… | |
608 | |
684 | |
609 | cancel $req |
685 | cancel $req |
610 | Cancels the request, if possible. Has the effect of skipping |
686 | Cancels the request, if possible. Has the effect of skipping |
611 | execution when entering the execute state and skipping calling the |
687 | execution when entering the execute state and skipping calling the |
612 | callback when entering the the result state, but will leave the |
688 | callback when entering the the result state, but will leave the |
613 | request otherwise untouched. That means that requests that currently |
689 | request otherwise untouched (with the exception of readdir). That |
614 | execute will not be stopped and resources held by the request will |
690 | means that requests that currently execute will not be stopped and |
615 | not be freed prematurely. |
691 | resources held by the request will not be freed prematurely. |
616 | |
692 | |
617 | cb $req $callback->(...) |
693 | cb $req $callback->(...) |
618 | Replace (or simply set) the callback registered to the request. |
694 | Replace (or simply set) the callback registered to the request. |
619 | |
695 | |
620 | IO::AIO::GRP CLASS |
696 | IO::AIO::GRP CLASS |
… | |
… | |
647 | }; |
723 | }; |
648 | |
724 | |
649 | This makes it very easy to create composite requests (see the source of |
725 | This makes it very easy to create composite requests (see the source of |
650 | "aio_move" for an application) that work and feel like simple requests. |
726 | "aio_move" for an application) that work and feel like simple requests. |
651 | |
727 | |
652 | * The IO::AIO::GRP objects will be cleaned up during calls to |
728 | * The IO::AIO::GRP objects will be cleaned up during calls to |
653 | "IO::AIO::poll_cb", just like any other request. |
729 | "IO::AIO::poll_cb", just like any other request. |
|
|
730 | |
654 | * They can be canceled like any other request. Canceling will cancel not |
731 | * They can be canceled like any other request. Canceling will cancel |
655 | only the request itself, but also all requests it contains. |
732 | not only the request itself, but also all requests it contains. |
|
|
733 | |
656 | * They can also can also be added to other IO::AIO::GRP objects. |
734 | * They can also can also be added to other IO::AIO::GRP objects. |
|
|
735 | |
657 | * You must not add requests to a group from within the group callback |
736 | * You must not add requests to a group from within the group callback |
658 | (or any later time). |
737 | (or any later time). |
659 | |
738 | |
660 | Their lifetime, simplified, looks like this: when they are empty, they |
739 | Their lifetime, simplified, looks like this: when they are empty, they |
661 | will finish very quickly. If they contain only requests that are in the |
740 | will finish very quickly. If they contain only requests that are in the |
662 | "done" state, they will also finish. Otherwise they will continue to |
741 | "done" state, they will also finish. Otherwise they will continue to |
663 | exist. |
742 | exist. |
664 | |
743 | |
665 | That means after creating a group you have some time to add requests. |
744 | That means after creating a group you have some time to add requests |
666 | And in the callbacks of those requests, you can add further requests to |
745 | (precisely before the callback has been invoked, which is only done |
667 | the group. And only when all those requests have finished will the the |
746 | within the "poll_cb"). And in the callbacks of those requests, you can |
668 | group itself finish. |
747 | add further requests to the group. And only when all those requests have |
|
|
748 | finished will the the group itself finish. |
669 | |
749 | |
670 | add $grp ... |
750 | add $grp ... |
671 | $grp->add (...) |
751 | $grp->add (...) |
672 | Add one or more requests to the group. Any type of IO::AIO::REQ can |
752 | Add one or more requests to the group. Any type of IO::AIO::REQ can |
673 | be added, including other groups, as long as you do not create |
753 | be added, including other groups, as long as you do not create |
… | |
… | |
680 | request itself. Useful when you queued a lot of events but got a |
760 | request itself. Useful when you queued a lot of events but got a |
681 | result early. |
761 | result early. |
682 | |
762 | |
683 | $grp->result (...) |
763 | $grp->result (...) |
684 | Set the result value(s) that will be passed to the group callback |
764 | Set the result value(s) that will be passed to the group callback |
685 | when all subrequests have finished and set thre groups errno to the |
765 | when all subrequests have finished and set the groups errno to the |
686 | current value of errno (just like calling "errno" without an error |
766 | current value of errno (just like calling "errno" without an error |
687 | number). By default, no argument will be passed and errno is zero. |
767 | number). By default, no argument will be passed and errno is zero. |
688 | |
768 | |
689 | $grp->errno ([$errno]) |
769 | $grp->errno ([$errno]) |
690 | Sets the group errno value to $errno, or the current value of errno |
770 | Sets the group errno value to $errno, or the current value of errno |
… | |
… | |
716 | does not impose any limits). |
796 | does not impose any limits). |
717 | |
797 | |
718 | If the feed does not queue more requests when called, it will be |
798 | If the feed does not queue more requests when called, it will be |
719 | automatically removed from the group. |
799 | automatically removed from the group. |
720 | |
800 | |
721 | If the feed limit is 0, it will be set to 2 automatically. |
801 | If the feed limit is 0 when this method is called, it will be set to |
|
|
802 | 2 automatically. |
722 | |
803 | |
723 | Example: |
804 | Example: |
724 | |
805 | |
725 | # stat all files in @files, but only ever use four aio requests concurrently: |
806 | # stat all files in @files, but only ever use four aio requests concurrently: |
726 | |
807 | |
… | |
… | |
737 | Sets the feeder limit for the group: The feeder will be called |
818 | Sets the feeder limit for the group: The feeder will be called |
738 | whenever the group contains less than this many requests. |
819 | whenever the group contains less than this many requests. |
739 | |
820 | |
740 | Setting the limit to 0 will pause the feeding process. |
821 | Setting the limit to 0 will pause the feeding process. |
741 | |
822 | |
|
|
823 | The default value for the limit is 0, but note that setting a feeder |
|
|
824 | automatically bumps it up to 2. |
|
|
825 | |
742 | SUPPORT FUNCTIONS |
826 | SUPPORT FUNCTIONS |
743 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
827 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
744 | $fileno = IO::AIO::poll_fileno |
828 | $fileno = IO::AIO::poll_fileno |
745 | Return the *request result pipe file descriptor*. This filehandle |
829 | Return the *request result pipe file descriptor*. This filehandle |
746 | must be polled for reading by some mechanism outside this module |
830 | must be polled for reading by some mechanism outside this module |
747 | (e.g. Event or select, see below or the SYNOPSIS). If the pipe |
831 | (e.g. EV, Glib, select and so on, see below or the SYNOPSIS). If the |
748 | becomes readable you have to call "poll_cb" to check the results. |
832 | pipe becomes readable you have to call "poll_cb" to check the |
|
|
833 | results. |
749 | |
834 | |
750 | See "poll_cb" for an example. |
835 | See "poll_cb" for an example. |
751 | |
836 | |
752 | IO::AIO::poll_cb |
837 | IO::AIO::poll_cb |
753 | Process some outstanding events on the result pipe. You have to call |
838 | Process some outstanding events on the result pipe. You have to call |
754 | this regularly. Returns the number of events processed. Returns |
839 | this regularly. Returns 0 if all events could be processed, or -1 if |
755 | immediately when no events are outstanding. The amount of events |
840 | it returned earlier for whatever reason. Returns immediately when no |
|
|
841 | events are outstanding. The amount of events processed depends on |
756 | processed depends on the settings of "IO::AIO::max_poll_req" and |
842 | the settings of "IO::AIO::max_poll_req" and |
757 | "IO::AIO::max_poll_time". |
843 | "IO::AIO::max_poll_time". |
758 | |
844 | |
759 | If not all requests were processed for whatever reason, the |
845 | If not all requests were processed for whatever reason, the |
760 | filehandle will still be ready when "poll_cb" returns. |
846 | filehandle will still be ready when "poll_cb" returns, so normally |
|
|
847 | you don't have to do anything special to have it called later. |
761 | |
848 | |
762 | Example: Install an Event watcher that automatically calls |
849 | Example: Install an Event watcher that automatically calls |
763 | IO::AIO::poll_cb with high priority: |
850 | IO::AIO::poll_cb with high priority (more examples can be found in |
|
|
851 | the SYNOPSIS section, at the top of this document): |
764 | |
852 | |
765 | Event->io (fd => IO::AIO::poll_fileno, |
853 | Event->io (fd => IO::AIO::poll_fileno, |
766 | poll => 'r', async => 1, |
854 | poll => 'r', async => 1, |
767 | cb => \&IO::AIO::poll_cb); |
855 | cb => \&IO::AIO::poll_cb); |
768 | |
856 | |
… | |
… | |
871 | |
959 | |
872 | The default is probably ok in most situations, especially if thread |
960 | The default is probably ok in most situations, especially if thread |
873 | creation is fast. If thread creation is very slow on your system you |
961 | creation is fast. If thread creation is very slow on your system you |
874 | might want to use larger values. |
962 | might want to use larger values. |
875 | |
963 | |
876 | $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
964 | IO::AIO::max_outstanding $maxreqs |
877 | This is a very bad function to use in interactive programs because |
965 | This is a very bad function to use in interactive programs because |
878 | it blocks, and a bad way to reduce concurrency because it is |
966 | it blocks, and a bad way to reduce concurrency because it is |
879 | inexact: Better use an "aio_group" together with a feed callback. |
967 | inexact: Better use an "aio_group" together with a feed callback. |
880 | |
968 | |
881 | Sets the maximum number of outstanding requests to $nreqs. If you do |
969 | Sets the maximum number of outstanding requests to $nreqs. If you do |
… | |
… | |
885 | |
973 | |
886 | The default value is very large, so there is no practical limit on |
974 | The default value is very large, so there is no practical limit on |
887 | the number of outstanding requests. |
975 | the number of outstanding requests. |
888 | |
976 | |
889 | You can still queue as many requests as you want. Therefore, |
977 | You can still queue as many requests as you want. Therefore, |
890 | "max_oustsanding" is mainly useful in simple scripts (with low |
978 | "max_outstanding" is mainly useful in simple scripts (with low |
891 | values) or as a stop gap to shield against fatal memory overflow |
979 | values) or as a stop gap to shield against fatal memory overflow |
892 | (with large values). |
980 | (with large values). |
893 | |
981 | |
894 | STATISTICAL INFORMATION |
982 | STATISTICAL INFORMATION |
895 | IO::AIO::nreqs |
983 | IO::AIO::nreqs |
… | |
… | |
907 | executed). |
995 | executed). |
908 | |
996 | |
909 | IO::AIO::npending |
997 | IO::AIO::npending |
910 | Returns the number of requests currently in the pending state |
998 | Returns the number of requests currently in the pending state |
911 | (executed, but not yet processed by poll_cb). |
999 | (executed, but not yet processed by poll_cb). |
|
|
1000 | |
|
|
1001 | MISCELLANEOUS FUNCTIONS |
|
|
1002 | IO::AIO implements some functions that might be useful, but are not |
|
|
1003 | asynchronous. |
|
|
1004 | |
|
|
1005 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
1006 | Calls the "eio_sendfile_sync" function, which is like |
|
|
1007 | "aio_sendfile", but is blocking (this makes most sense if you know |
|
|
1008 | the input data is likely cached already and the output filehandle is |
|
|
1009 | set to non-blocking operations). |
|
|
1010 | |
|
|
1011 | Returns the number of bytes copied, or -1 on error. |
|
|
1012 | |
|
|
1013 | IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
1014 | Simply calls the "posix_fadvise" function (see it's manpage for |
|
|
1015 | details). The following advice constants are avaiable: |
|
|
1016 | "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", |
|
|
1017 | "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", |
|
|
1018 | "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". |
|
|
1019 | |
|
|
1020 | On systems that do not implement "posix_fadvise", this function |
|
|
1021 | returns ENOSYS, otherwise the return value of "posix_fadvise". |
912 | |
1022 | |
913 | FORK BEHAVIOUR |
1023 | FORK BEHAVIOUR |
914 | This module should do "the right thing" when the process using it forks: |
1024 | This module should do "the right thing" when the process using it forks: |
915 | |
1025 | |
916 | Before the fork, IO::AIO enters a quiescent state where no requests can |
1026 | Before the fork, IO::AIO enters a quiescent state where no requests can |
… | |
… | |
945 | |
1055 | |
946 | KNOWN BUGS |
1056 | KNOWN BUGS |
947 | Known bugs will be fixed in the next release. |
1057 | Known bugs will be fixed in the next release. |
948 | |
1058 | |
949 | SEE ALSO |
1059 | SEE ALSO |
950 | Coro::AIO. |
1060 | AnyEvent::AIO for easy integration into event loops, Coro::AIO for a |
|
|
1061 | more natural syntax. |
951 | |
1062 | |
952 | AUTHOR |
1063 | AUTHOR |
953 | Marc Lehmann <schmorp@schmorp.de> |
1064 | Marc Lehmann <schmorp@schmorp.de> |
954 | http://home.schmorp.de/ |
1065 | http://home.schmorp.de/ |
955 | |
1066 | |