… | |
… | |
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, urxvt, pureperl...) |
29 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
30 | open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; |
30 | use AnyEvent::AIO; |
31 | my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); |
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32 | |
31 | |
33 | # EV integration |
32 | # EV integration |
34 | my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
33 | my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
35 | |
34 | |
36 | # Event integration |
35 | # Event integration |
… | |
… | |
176 | All the "aio_*" calls are more or less thin wrappers around the syscall |
175 | All the "aio_*" calls are more or less thin wrappers around the syscall |
177 | with the same name (sans "aio_"). The arguments are similar or |
176 | with the same name (sans "aio_"). The arguments are similar or |
178 | identical, and they all accept an additional (and optional) $callback |
177 | identical, and they all accept an additional (and optional) $callback |
179 | argument which must be a code reference. This code reference will get |
178 | argument which must be a code reference. This code reference will get |
180 | called with the syscall return code (e.g. most syscalls return -1 on |
179 | called with the syscall return code (e.g. most syscalls return -1 on |
181 | error, unlike perl, which usually delivers "false") as it's sole |
180 | error, unlike perl, which usually delivers "false") as its sole argument |
182 | argument when the given syscall has been executed asynchronously. |
181 | after the given syscall has been executed asynchronously. |
183 | |
182 | |
184 | All functions expecting a filehandle keep a copy of the filehandle |
183 | All functions expecting a filehandle keep a copy of the filehandle |
185 | internally until the request has finished. |
184 | internally until the request has finished. |
186 | |
185 | |
187 | All functions return request objects of type IO::AIO::REQ that allow |
186 | All functions return request objects of type IO::AIO::REQ that allow |
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200 | the user environment, d) use Glib::filename_from_unicode on unicode |
199 | the user environment, d) use Glib::filename_from_unicode on unicode |
201 | filenames or e) use something else to ensure your scalar has the correct |
200 | filenames or e) use something else to ensure your scalar has the correct |
202 | contents. |
201 | contents. |
203 | |
202 | |
204 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
203 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
205 | handles correctly wether it is set or not. |
204 | handles correctly whether it is set or not. |
206 | |
205 | |
207 | $prev_pri = aioreq_pri [$pri] |
206 | $prev_pri = aioreq_pri [$pri] |
208 | Returns the priority value that would be used for the next request |
207 | Returns the priority value that would be used for the next request |
209 | and, if $pri is given, sets the priority for the next aio request. |
208 | and, if $pri is given, sets the priority for the next aio request. |
210 | |
209 | |
… | |
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265 | Asynchronously close a file and call the callback with the result |
264 | Asynchronously close a file and call the callback with the result |
266 | code. |
265 | code. |
267 | |
266 | |
268 | Unfortunately, you can't do this to perl. Perl *insists* very |
267 | Unfortunately, you can't do this to perl. Perl *insists* very |
269 | strongly on closing the file descriptor associated with the |
268 | strongly on closing the file descriptor associated with the |
270 | filehandle itself. Here is what aio_close will try: |
269 | filehandle itself. |
271 | |
270 | |
272 | 1. dup()licate the fd |
271 | Therefore, "aio_close" will not close the filehandle - instead it |
273 | 2. asynchronously close() the duplicated fd |
272 | will use dup2 to overwrite the file descriptor with the write-end of |
274 | 3. dup()licate the fd once more |
273 | a pipe (the pipe fd will be created on demand and will be cached). |
275 | 4. let perl close() the filehandle |
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276 | 5. asynchronously close the duplicated fd |
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277 | |
274 | |
278 | The idea is that the first close() flushes stuff to disk that |
275 | Or in other words: the file descriptor will be closed, but it will |
279 | closing an fd will flush, so when perl closes the fd, nothing much |
276 | not be free for reuse until the perl filehandle is closed. |
280 | will need to be flushed. The second async. close() will then flush |
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281 | stuff to disk that closing the last fd to the file will flush. |
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282 | |
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283 | Just FYI, SuSv3 has this to say on close: |
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284 | |
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285 | All outstanding record locks owned by the process on the file |
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286 | associated with the file descriptor shall be removed. |
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287 | |
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288 | If fildes refers to a socket, close() shall cause the socket to be |
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289 | destroyed. ... close() shall block for up to the current linger |
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290 | interval until all data is transmitted. |
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291 | [this actually sounds like a specification bug, but who knows] |
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292 | |
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293 | And at least Linux additionally actually flushes stuff on every |
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294 | close, even when the file itself is still open. |
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295 | |
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296 | Sounds enourmously inefficient and complicated? Yes... please show |
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297 | me how to nuke perl's fd out of existence... |
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298 | |
277 | |
299 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
278 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
300 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
279 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
301 | Reads or writes $length bytes from the specified $fh and $offset |
280 | Reads or writes $length bytes from the specified $fh and $offset |
302 | into the scalar given by $data and offset $dataoffset and calls the |
281 | into the scalar given by $data and offset $dataoffset and calls the |
… | |
… | |
472 | aio_copy $srcpath, $dstpath, $callback->($status) |
451 | aio_copy $srcpath, $dstpath, $callback->($status) |
473 | Try to copy the *file* (directories not supported as either source |
452 | Try to copy the *file* (directories not supported as either source |
474 | or destination) from $srcpath to $dstpath and call the callback with |
453 | or destination) from $srcpath to $dstpath and call the callback with |
475 | the 0 (error) or -1 ok. |
454 | the 0 (error) or -1 ok. |
476 | |
455 | |
477 | This is a composite request that it creates the destination file |
456 | This is a composite request that creates the destination file with |
478 | with mode 0200 and copies the contents of the source file into it |
457 | mode 0200 and copies the contents of the source file into it using |
479 | using "aio_sendfile", followed by restoring atime, mtime, access |
458 | "aio_sendfile", followed by restoring atime, mtime, access mode and |
480 | mode and uid/gid, in that order. |
459 | uid/gid, in that order. |
481 | |
460 | |
482 | If an error occurs, the partial destination file will be unlinked, |
461 | If an error occurs, the partial destination file will be unlinked, |
483 | if possible, except when setting atime, mtime, access mode and |
462 | if possible, except when setting atime, mtime, access mode and |
484 | uid/gid, where errors are being ignored. |
463 | uid/gid, where errors are being ignored. |
485 | |
464 | |
… | |
… | |
565 | If this call isn't available because your OS lacks it or it couldn't |
544 | If this call isn't available because your OS lacks it or it couldn't |
566 | be detected, it will be emulated by calling "fsync" instead. |
545 | be detected, it will be emulated by calling "fsync" instead. |
567 | |
546 | |
568 | aio_pathsync $path, $callback->($status) |
547 | aio_pathsync $path, $callback->($status) |
569 | This request tries to open, fsync and close the given path. This is |
548 | This request tries to open, fsync and close the given path. This is |
570 | a composite request intended tosync directories after directory |
549 | a composite request intended to sync directories after directory |
571 | operations (E.g. rename). This might not work on all operating |
550 | operations (E.g. rename). This might not work on all operating |
572 | systems or have any specific effect, but usually it makes sure that |
551 | systems or have any specific effect, but usually it makes sure that |
573 | directory changes get written to disc. It works for anything that |
552 | directory changes get written to disc. It works for anything that |
574 | can be opened for read-only, not just directories. |
553 | can be opened for read-only, not just directories. |
575 | |
554 | |
… | |
… | |
679 | Their lifetime, simplified, looks like this: when they are empty, they |
658 | Their lifetime, simplified, looks like this: when they are empty, they |
680 | will finish very quickly. If they contain only requests that are in the |
659 | will finish very quickly. If they contain only requests that are in the |
681 | "done" state, they will also finish. Otherwise they will continue to |
660 | "done" state, they will also finish. Otherwise they will continue to |
682 | exist. |
661 | exist. |
683 | |
662 | |
684 | That means after creating a group you have some time to add requests. |
663 | That means after creating a group you have some time to add requests |
685 | And in the callbacks of those requests, you can add further requests to |
664 | (precisely before the callback has been invoked, which is only done |
686 | the group. And only when all those requests have finished will the the |
665 | within the "poll_cb"). And in the callbacks of those requests, you can |
687 | group itself finish. |
666 | add further requests to the group. And only when all those requests have |
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|
667 | finished will the the group itself finish. |
688 | |
668 | |
689 | add $grp ... |
669 | add $grp ... |
690 | $grp->add (...) |
670 | $grp->add (...) |
691 | Add one or more requests to the group. Any type of IO::AIO::REQ can |
671 | Add one or more requests to the group. Any type of IO::AIO::REQ can |
692 | be added, including other groups, as long as you do not create |
672 | be added, including other groups, as long as you do not create |
… | |
… | |
768 | |
748 | |
769 | See "poll_cb" for an example. |
749 | See "poll_cb" for an example. |
770 | |
750 | |
771 | IO::AIO::poll_cb |
751 | IO::AIO::poll_cb |
772 | Process some outstanding events on the result pipe. You have to call |
752 | Process some outstanding events on the result pipe. You have to call |
773 | this regularly. Returns the number of events processed. Returns |
753 | this regularly. Returns 0 if all events could be processed, or -1 if |
774 | immediately when no events are outstanding. The amount of events |
754 | it returned earlier for whatever reason. Returns immediately when no |
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|
755 | events are outstanding. The amount of events processed depends on |
775 | processed depends on the settings of "IO::AIO::max_poll_req" and |
756 | the settings of "IO::AIO::max_poll_req" and |
776 | "IO::AIO::max_poll_time". |
757 | "IO::AIO::max_poll_time". |
777 | |
758 | |
778 | If not all requests were processed for whatever reason, the |
759 | If not all requests were processed for whatever reason, the |
779 | filehandle will still be ready when "poll_cb" returns. |
760 | filehandle will still be ready when "poll_cb" returns, so normally |
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|
761 | you don't have to do anything special to have it called later. |
780 | |
762 | |
781 | Example: Install an Event watcher that automatically calls |
763 | Example: Install an Event watcher that automatically calls |
782 | IO::AIO::poll_cb with high priority: |
764 | IO::AIO::poll_cb with high priority: |
783 | |
765 | |
784 | Event->io (fd => IO::AIO::poll_fileno, |
766 | Event->io (fd => IO::AIO::poll_fileno, |
… | |
… | |
890 | |
872 | |
891 | The default is probably ok in most situations, especially if thread |
873 | The default is probably ok in most situations, especially if thread |
892 | creation is fast. If thread creation is very slow on your system you |
874 | creation is fast. If thread creation is very slow on your system you |
893 | might want to use larger values. |
875 | might want to use larger values. |
894 | |
876 | |
895 | $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
877 | IO::AIO::max_outstanding $maxreqs |
896 | This is a very bad function to use in interactive programs because |
878 | This is a very bad function to use in interactive programs because |
897 | it blocks, and a bad way to reduce concurrency because it is |
879 | it blocks, and a bad way to reduce concurrency because it is |
898 | inexact: Better use an "aio_group" together with a feed callback. |
880 | inexact: Better use an "aio_group" together with a feed callback. |
899 | |
881 | |
900 | Sets the maximum number of outstanding requests to $nreqs. If you do |
882 | Sets the maximum number of outstanding requests to $nreqs. If you do |
… | |
… | |
904 | |
886 | |
905 | The default value is very large, so there is no practical limit on |
887 | The default value is very large, so there is no practical limit on |
906 | the number of outstanding requests. |
888 | the number of outstanding requests. |
907 | |
889 | |
908 | You can still queue as many requests as you want. Therefore, |
890 | You can still queue as many requests as you want. Therefore, |
909 | "max_oustsanding" is mainly useful in simple scripts (with low |
891 | "max_outstanding" is mainly useful in simple scripts (with low |
910 | values) or as a stop gap to shield against fatal memory overflow |
892 | values) or as a stop gap to shield against fatal memory overflow |
911 | (with large values). |
893 | (with large values). |
912 | |
894 | |
913 | STATISTICAL INFORMATION |
895 | STATISTICAL INFORMATION |
914 | IO::AIO::nreqs |
896 | IO::AIO::nreqs |
… | |
… | |
964 | |
946 | |
965 | KNOWN BUGS |
947 | KNOWN BUGS |
966 | Known bugs will be fixed in the next release. |
948 | Known bugs will be fixed in the next release. |
967 | |
949 | |
968 | SEE ALSO |
950 | SEE ALSO |
969 | Coro::AIO. |
951 | AnyEvent::AIO for easy integration into event loops, Coro::AIO for a |
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|
952 | more natural syntax. |
970 | |
953 | |
971 | AUTHOR |
954 | AUTHOR |
972 | Marc Lehmann <schmorp@schmorp.de> |
955 | Marc Lehmann <schmorp@schmorp.de> |
973 | http://home.schmorp.de/ |
956 | http://home.schmorp.de/ |
974 | |
957 | |