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Comparing Linux-AIO/AIO.pm (file contents):
Revision 1.11 by root, Tue Apr 2 14:01:09 2002 UTC vs.
Revision 1.20 by root, Wed Jan 12 20:37:11 2005 UTC

… …
6 6
7 use Linux::AIO; 7 use Linux::AIO;
8 8
9=head1 DESCRIPTION 9=head1 DESCRIPTION
10 10
11This module implements asynchroneous i/o using the means available to 11This module implements asynchronous i/o using the means available to linux
12linux - clone. It does not hook into the POSIX aio_* functions because 12- clone. It does not hook into the POSIX aio_* functions because linux
13linux does not yet support these in the kernel. Instead, a number of 13does not yet support these in the kernel (and even if, it would only allow
14threads are started that execute your read/writes and signal their 14aio_read and write, not open and stat).
15completion. 15
16Instead, in this module a number of (non-posix) threads are started that
17execute your read/writes and signal their completion. You don't need
18thread support in your libc or perl, and the threads created by this
19module will not be visible to the pthreads library.
20
21NOTICE: the threads created by this module will automatically be killed
22when the thread calling min_parallel exits. Make sure you only ever call
23min_parallel from the same thread that loaded this module.
24
25Although the module will work with threads, it is not reentrant, so use
26appropriate locking yourself.
16 27
17=over 4 28=over 4
18 29
19=cut 30=cut
20 31
21package Linux::AIO; 32package Linux::AIO;
22 33
23use base 'Exporter'; 34use base 'Exporter';
24 35
25BEGIN { 36BEGIN {
26 $VERSION = 0.1; 37 $VERSION = 1.3;
27 38
28 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat); 39 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink);
29 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs); 40 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs);
30 41
31 require XSLoader; 42 require XSLoader;
32 XSLoader::load Linux::AIO, $VERSION; 43 XSLoader::load Linux::AIO, $VERSION;
33} 44}
34 45
35=item Linux::AIO::min_parallel($nthreads) 46=item Linux::AIO::min_parallel $nthreads
36 47
37Set the minimum number of AIO threads to $nthreads. You I<have> to call 48Set the minimum number of AIO threads to C<$nthreads>. The default is
38this function with a positive number at leats once, otherwise no threads 49C<1>, which means a single asynchronous operation can be done at one time
39will be started and you aio-operations will seem to hang. 50(the number of outstanding operations, however, is unlimited).
51
52It is recommended to keep the number of threads low, as many linux
53kernel versions will scale negatively with the number of threads (higher
54parallelity => MUCH higher latency).
40 55
41=item $fileno = Linux::AIO::poll_fileno 56=item $fileno = Linux::AIO::poll_fileno
42 57
43Return the request result pipe filehandle. This filehandle must be polled 58Return the I<request result pipe filehandle>. This filehandle must be
44for reading. If the pipe becomes readable you have to call C<poll_cb>. 59polled for reading by some mechanism outside this module (e.g. Event
60or select, see below). If the pipe becomes readable you have to call
61C<poll_cb> to check the results.
45 62
46=item Linux::AIO::poll_cb 63=item Linux::AIO::poll_cb
47 64
48Process all outstanding events on the result pipe. You have to call this 65Process all outstanding events on the result pipe. You have to call this
49regularly. Returns the number of events processed. 66regularly. Returns the number of events processed. Returns immediately
67when no events are outstanding.
50 68
51You can use Event to multiplex, e.g.: 69You can use Event to multiplex, e.g.:
52 70
53 Event->io(fd => Linux::AIO::poll_fileno, 71 Event->io (fd => Linux::AIO::poll_fileno,
54 poll => 'r', async => 1, 72 poll => 'r', async => 1,
55 cb => \&Linux::AIO::poll_cb ); 73 cb => \&Linux::AIO::poll_cb );
56 74
57 75
58=item Linux::AIO::nreqs 76=item Linux::AIO::nreqs
59 77
60Returns the number of requests currently outstanding. 78Returns the number of requests currently outstanding.
61 79
62=item aio_open($pathname, $flags, $mode, $callback) 80=item aio_open $pathname, $flags, $mode, $callback
63 81
64Asynchronously open or create a file and call the callback with the 82Asynchronously open or create a file and call the callback with the
65filedescriptor. 83filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this
84might change in the future).
66 85
67=item aio_close($fh, $callback) 86=item aio_close $fh, $callback
68 87
69Asynchronously close a file and call the callback with the result code. 88Asynchronously close a file and call the callback with the result code.
70 89
71=item aio_read($fh,$offset,$length, $data,$dataoffset,$callback) 90=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
72 91
73=item aio_write($fh,$offset,$length, $data,$dataoffset,$callback) 92=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
74 93
75Reads or writes C<length> bytes from the specified C<fh> and C<offset> 94Reads or writes C<length> bytes from the specified C<fh> and C<offset>
76into the scalar given by C<data> and offset C<dataoffset> and calls the 95into the scalar given by C<data> and offset C<dataoffset> and calls the
77callback without the actual number of bytes read (or undef on error). 96callback without the actual number of bytes read (or C<undef> on error).
78 97
79=item aio_stat($fh_or_path,$callback) 98=item aio_stat $fh_or_path, $callback
80 99
81=item aio_lstat($fh,$callback) 100=item aio_lstat $fh, $callback
82 101
83Works like perl's C<stat> or C<lstat> in void context, i.e. the callback 102Works like perl's C<stat> or C<lstat> in void context. The callback will
84will be called after the stat and the results will be available using 103be called after the stat and the results will be available using C<stat _>
85C<stat _> or C<-s _> etc... 104or C<-s _> etc...
86 105
87Currently, the stats are always 64-bit-stats, i.e. instead of returning an 106Currently, the stats are always 64-bit-stats, i.e. instead of returning an
88error when stat'ing a large file, the results will be silently truncated 107error when stat'ing a large file, the results will be silently truncated
89unless perl itself is compiled with large file support. 108unless perl itself is compiled with large file support.
90 109
110=item aio_unlink $pathname, $callback
111
112Asynchronously unlink a file.
113
91=cut 114=cut
115
116min_parallel 1;
92 117
93END { 118END {
94 max_parallel 0; 119 max_parallel 0;
95} 120}
96 121
… …
98 123
99=back 124=back
100 125
101=head1 BUGS 126=head1 BUGS
102 127
103This module has not yet been extensively tested. Watch out! 128This module has been extensively tested in a large and very busy webserver
129for many years now.
104 130
105 - perl-threads/fork interaction poorly tested.
106 - aio_open gives a fd, but all other functions expect a filehandle. 131 - aio_open gives a fd, but all other functions expect a perl filehandle.
107 132
108=head1 SEE ALSO 133=head1 SEE ALSO
109 134
110L<Coro>. 135L<Coro>.
111 136
112=head1 AUTHOR 137=head1 AUTHOR
113 138
114 Marc Lehmann <pcg@goof.com> 139 Marc Lehmann <pcg@goof.com>
115 http://www.goof.com/pcg/marc/ 140 http://home.schmorp.de/
116 141
117=cut 142=cut
118 143

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