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Comparing Linux-AIO/AIO.pm (file contents):
Revision 1.2 by root, Tue Aug 14 18:06:37 2001 UTC vs.
Revision 1.18 by root, Sun Jul 18 10:58:00 2004 UTC

… …
6 6
7 use Linux::AIO; 7 use Linux::AIO;
8 8
9=head1 DESCRIPTION 9=head1 DESCRIPTION
10 10
11This module implements asynchronous i/o using the means available to linux
12- clone. It does not hook into the POSIX aio_* functions because linux
13does not yet support these in the kernel (and even if, it would only allow
14aio_read and write, not open and stat).
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.
27
11=over 4 28=over 4
12 29
13=cut 30=cut
14 31
15package Linux::AIO; 32package Linux::AIO;
16 33
17use base 'Exporter'; 34use base 'Exporter';
18 35
19BEGIN { 36BEGIN {
20 $VERSION = 0.001; 37 $VERSION = 1.2;
21 38
22 @EXPORT = qw(aio_read aio_write); 39 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink);
23 @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);
24 41
25 require XSLoader; 42 require XSLoader;
26 XSLoader::load Linux::AIO, $VERSION; 43 XSLoader::load Linux::AIO, $VERSION;
27} 44}
28 45
29=item Linux::AIO::min_parallel($nthreads) 46=item Linux::AIO::min_parallel $nthreads
30 47
31Set the minimum number of AIO threads to $nthreads. 48Set the minimum number of AIO threads to C<$nthreads>. The default is
49C<1>, which means a single asynchronous operation can be done at one time
50(the number of outstanding operations, however, is unlimited).
32 51
33=cut 52It is recommended to keep the number of threads low, as many linux
34 53kernel versions will scale negatively with the number of threads (higher
35=item aio_read($fh,$offset,$length, $data,$dataoffset,$callback) 54parallelity => MUCH higher latency).
36aio_write($fh,$offset,$length, $data,$dataoffset,$callback)
37
38Reads or writes C<length> bytes from the specified C<fh> and C<offset>
39into the scalar given by C<data> and offset C<dataoffset> and calls the
40callback without the actual number of bytes read (or undef on error).
41 55
42=item $fileno = Linux::AIO::poll_fileno 56=item $fileno = Linux::AIO::poll_fileno
43 57
44Return the request result pipe filehandle. This filehandle must be polled 58Return the I<request result pipe filehandle>. This filehandle must be
45for 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.
46 62
47=item Linux::AIO::poll_cb 63=item Linux::AIO::poll_cb
48 64
49Process 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
50regularly. Returns the number of events processed. 66regularly. Returns the number of events processed. Returns immediately
67when no events are outstanding.
68
69You can use Event to multiplex, e.g.:
70
71 Event->io (fd => Linux::AIO::poll_fileno,
72 poll => 'r', async => 1,
73 cb => \&Linux::AIO::poll_cb );
74
51 75
52=item Linux::AIO::nreqs 76=item Linux::AIO::nreqs
53 77
54Returns the number of requests currently outstanding. 78Returns the number of requests currently outstanding.
55 79
80=item aio_open $pathname, $flags, $mode, $callback
81
82Asynchronously open or create a file and call the callback with the
83filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this
84might change in the future).
85
86=item aio_close $fh, $callback
87
88Asynchronously close a file and call the callback with the result code.
89
90=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
91
92=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
93
94Reads or writes C<length> bytes from the specified C<fh> and C<offset>
95into the scalar given by C<data> and offset C<dataoffset> and calls the
96callback without the actual number of bytes read (or C<undef> on error).
97
98=item aio_stat $fh_or_path, $callback
99
100=item aio_lstat $fh, $callback
101
102Works like perl's C<stat> or C<lstat> in void context. The callback will
103be called after the stat and the results will be available using C<stat _>
104or C<-s _> etc...
105
106Currently, the stats are always 64-bit-stats, i.e. instead of returning an
107error when stat'ing a large file, the results will be silently truncated
108unless perl itself is compiled with large file support.
109
110=item aio_unlink $pathname, $callback
111
112Asynchronously unlink a file.
113
56=cut 114=cut
115
116min_parallel 1;
57 117
58END { 118END {
59 max_parallel 0; 119 max_parallel 0;
60} 120}
61 121
… …
63 123
64=back 124=back
65 125
66=head1 BUGS 126=head1 BUGS
67 127
68This 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.
69 130
70This module does not use the aio_* posix functions because a) linux does 131 - aio_open gives a fd, but all other functions expect a perl filehandle.
71not have aio, b) the existing aio_* functions use pthreads, which are too
72buggy for my usage.
73 132
74=head1 SEE ALSO 133=head1 SEE ALSO
75 134
76L<Coro>. 135L<Coro>.
77 136

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