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Revision 1.67 by root, Tue Oct 24 02:25:16 2006 UTC vs.
Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC

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18 }; 18 };
19 19
20 # version 2+ has request and group objects 20 # version 2+ has request and group objects
21 use IO::AIO 2; 21 use IO::AIO 2;
22 22
23 aioreq_pri 4; # give next request a very high priority
23 my $req = aio_unlink "/tmp/file", sub { }; 24 my $req = aio_unlink "/tmp/file", sub { };
24 $req->cancel; # cancel request if still in queue 25 $req->cancel; # cancel request if still in queue
25 26
26 my $grp = aio_group sub { print "all stats done\n" }; 27 my $grp = aio_group sub { print "all stats done\n" };
27 add $grp aio_stat "..." for ...; 28 add $grp aio_stat "..." for ...;
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59on many operating systems. However, they are often not well-supported 60on many operating systems. However, they are often not well-supported
60(Linux doesn't allow them on normal files currently, for example), 61(Linux doesn't allow them on normal files currently, for example),
61and they would only support aio_read and aio_write, so the remaining 62and they would only support aio_read and aio_write, so the remaining
62functionality would have to be implemented using threads anyway. 63functionality would have to be implemented using threads anyway.
63 64
64Although the module will work with in the presence of other threads, it is 65Although the module will work with in the presence of other threads,
65currently not reentrant, so use appropriate locking yourself, always call 66it is currently not reentrant in any way, so use appropriate locking
66C<poll_cb> from within the same thread, or never call C<poll_cb> (or other 67yourself, always call C<poll_cb> from within the same thread, or never
67C<aio_> functions) recursively. 68call C<poll_cb> (or other C<aio_> functions) recursively.
68 69
69=cut 70=cut
70 71
71package IO::AIO; 72package IO::AIO;
72 73
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80 81
81 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 82 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
82 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 83 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
83 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 84 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
84 aio_group aio_nop); 85 aio_group aio_nop);
85 our @EXPORT = (@AIO_REQ, qw(aioreq_pri)); 86 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
86 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 87 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
87 min_parallel max_parallel max_outstanding nreqs); 88 min_parallel max_parallel max_outstanding nreqs);
88 89
89 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 90 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
90 91
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122your pathnames to the locale (or other) encoding in effect in the user 123your pathnames to the locale (or other) encoding in effect in the user
123environment, d) use Glib::filename_from_unicode on unicode filenames or e) 124environment, d) use Glib::filename_from_unicode on unicode filenames or e)
124use something else. 125use something else.
125 126
126=over 4 127=over 4
128
129=item aioreq_pri $pri
130
131Sets the priority for the next aio request. The default priority
132is C<0>, the minimum and maximum priorities are C<-4> and C<4>,
133respectively. Requests with higher priority will be serviced first.
134
135The priority will be reset to C<0> after each call to one of the C<aio_>
136functions.
137
138Example: open a file with low priority, then read something from it with
139higher priority so the read request is serviced before other low priority
140open requests (potentially spamming the cache):
141
142 aioreq_pri -3;
143 aio_open ..., sub {
144 return unless $_[0];
145
146 aioreq_pri -2;
147 aio_read $_[0], ..., sub {
148 ...
149 };
150 };
151
152=item aioreq_nice $pri_adjust
153
154Similar to C<aioreq_pri>, but subtracts the given value from the current
155priority, so effects are cumulative.
127 156
128=item aio_open $pathname, $flags, $mode, $callback->($fh) 157=item aio_open $pathname, $flags, $mode, $callback->($fh)
129 158
130Asynchronously open or create a file and call the callback with a newly 159Asynchronously open or create a file and call the callback with a newly
131created filehandle for the file. 160created filehandle for the file.
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681example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 710example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
682requests, delaying any later requests for a long time. 711requests, delaying any later requests for a long time.
683 712
684To avoid this, and allow incremental generation of requests, you can 713To avoid this, and allow incremental generation of requests, you can
685instead a group and set a feeder on it that generates those requests. The 714instead a group and set a feeder on it that generates those requests. The
686feed callback will be called whenever there are few enough (see C<feed_limit>, 715feed callback will be called whenever there are few enough (see C<limit>,
687below) requests active in the group itself and is expected to queue more 716below) requests active in the group itself and is expected to queue more
688requests. 717requests.
689 718
690The feed can queue as many requests as it likes (i.e. C<add> does not 719The feed callback can queue as many requests as it likes (i.e. C<add> does
691impose any limits). 720not impose any limits).
692 721
693If the feed does not queue more requests when called, it will be 722If the feed does not queue more requests when called, it will be
694automatically removed from the group. 723automatically removed from the group.
695 724
696If the feed limit is C<0>, it will be set to C<2> automatically. 725If the feed limit is C<0>, it will be set to C<2> automatically.
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698Example: 727Example:
699 728
700 # stat all files in @files, but only ever use four aio requests concurrently: 729 # stat all files in @files, but only ever use four aio requests concurrently:
701 730
702 my $grp = aio_group sub { print "finished\n" }; 731 my $grp = aio_group sub { print "finished\n" };
703 feed_limit $grp 4; 732 limit $grp 4;
704 feed $grp sub { 733 feed $grp sub {
705 my $file = pop @files 734 my $file = pop @files
706 or return; 735 or return;
707 736
708 add $grp aio_stat $file, sub { ... }; 737 add $grp aio_stat $file, sub { ... };
709 }; 738 };
710 739
711=item feed_limit $grp $num 740=item limit $grp $num
712 741
713Sets the feeder limit for the group: The feeder will be called whenever 742Sets the feeder limit for the group: The feeder will be called whenever
714the group contains less than this many requests. 743the group contains less than this many requests.
715 744
716Setting the limit to C<0> will pause the feeding process. 745Setting the limit to C<0> will pause the feeding process.
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886Each thread needs a stack area which is usually around 16k, sometimes much 915Each thread needs a stack area which is usually around 16k, sometimes much
887larger, depending on the OS. 916larger, depending on the OS.
888 917
889=head1 SEE ALSO 918=head1 SEE ALSO
890 919
891L<Coro>, L<Linux::AIO> (obsolete). 920L<Coro::AIO>.
892 921
893=head1 AUTHOR 922=head1 AUTHOR
894 923
895 Marc Lehmann <schmorp@schmorp.de> 924 Marc Lehmann <schmorp@schmorp.de>
896 http://home.schmorp.de/ 925 http://home.schmorp.de/

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