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Comparing Linux-AIO/AIO.pm (file contents):
Revision 1.3 by root, Tue Aug 14 23:25:39 2001 UTC vs.
Revision 1.27 by root, Fri Jul 8 02:43:47 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 (even as of 2.6.12, only O_DIRECT
14threads are started that execute your read/writes and signal their 14files are supported) and even if, it would only allow aio_read and write,
15completion. 15not open, stat and so on.
16
17Instead, in this module a number of (non-posix) threads are started that
18execute your read/writes and signal their completion. You don't need
19thread support in your libc or perl, and the threads created by this
20module will not be visible to the pthreads library.
21
22NOTICE: the threads created by this module will automatically be killed
23when the thread calling min_parallel exits. Make sure you only ever call
24min_parallel from the same thread that loaded this module.
25
26Although the module will work with in the presence of other threads, it is
27not reentrant, so use appropriate locking yourself.
16 28
17=over 4 29=over 4
18 30
19=cut 31=cut
20 32
21package Linux::AIO; 33package Linux::AIO;
22 34
23use base 'Exporter'; 35use base 'Exporter';
24 36
25BEGIN { 37BEGIN {
26 $VERSION = 0.001; 38 $VERSION = 1.6;
27 39
28 @EXPORT = qw(aio_read aio_write); 40 @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); 41 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs);
30 42
31 require XSLoader; 43 require XSLoader;
32 XSLoader::load Linux::AIO, $VERSION; 44 XSLoader::load Linux::AIO, $VERSION;
33} 45}
34 46
35=item Linux::AIO::min_parallel($nthreads) 47=item Linux::AIO::min_parallel $nthreads
36 48
37Set the minimum number of AIO threads to $nthreads. You I<have> to call 49Set the minimum number of AIO threads to C<$nthreads>. The default is
38this function with a positive number at leats once, otherwise no threads 50C<1>, which means a single asynchronous operation can be done at one time
39will be started and you aio-operations will seem to hang. 51(the number of outstanding operations, however, is unlimited).
40 52
41=cut 53It is recommended to keep the number of threads low, as some linux
54kernel versions will scale negatively with the number of threads (higher
55parallelity => MUCH higher latency).
42 56
43=item aio_read($fh,$offset,$length, $data,$dataoffset,$callback) 57=item Linux::AIO::max_parallel $nthreads
44aio_write($fh,$offset,$length, $data,$dataoffset,$callback)
45 58
46Reads or writes C<length> bytes from the specified C<fh> and C<offset> 59Sets the maximum number of AIO threads to C<$nthreads>. If more than
47into the scalar given by C<data> and offset C<dataoffset> and calls the 60the specified number of threads are currently running, kill them. This
48callback without the actual number of bytes read (or undef on error). 61function blocks until the limit is reached.
62
63This module automatically runs C<max_parallel 0> at program end, to ensure
64that all threads are killed and that there are no outstanding requests.
49 65
50=item $fileno = Linux::AIO::poll_fileno 66=item $fileno = Linux::AIO::poll_fileno
51 67
52Return the request result pipe filehandle. This filehandle must be polled 68Return the I<request result pipe filehandle>. This filehandle must be
53for reading. If the pipe becomes readable you have to call C<poll_cb>. 69polled for reading by some mechanism outside this module (e.g. Event
70or select, see below). If the pipe becomes readable you have to call
71C<poll_cb> to check the results.
54 72
55=item Linux::AIO::poll_cb 73=item Linux::AIO::poll_cb
56 74
57Process all outstanding events on the result pipe. You have to call this 75Process all outstanding events on the result pipe. You have to call this
58regularly. Returns the number of events processed. 76regularly. Returns the number of events processed. Returns immediately
77when no events are outstanding.
59 78
60You can use Event to multiplex, e.g.: 79You can use Event to multiplex, e.g.:
61 80
62 Event->io(fd => Linux::AIO::poll_fileno, 81 Event->io (fd => Linux::AIO::poll_fileno,
63 poll => 'r', async => 1, 82 poll => 'r', async => 1,
64 cb => \&Linux::AIO::poll_cb ); 83 cb => \&Linux::AIO::poll_cb );
65 84
85=item Linux::AIO::poll_wait
86
87Wait till the result filehandle becomes ready for reading (simply does a
88select on the filehandle. This is useful if you want to synchronously wait
89for some requests to finish).
66 90
67=item Linux::AIO::nreqs 91=item Linux::AIO::nreqs
68 92
69Returns the number of requests currently outstanding. 93Returns the number of requests currently outstanding.
70 94
95=item aio_open $pathname, $flags, $mode, $callback
96
97Asynchronously open or create a file and call the callback with the
98filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this
99might change in the future).
100
101=item aio_close $fh, $callback
102
103Asynchronously close a file and call the callback with the result code.
104
105=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
106
107=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
108
109Reads or writes C<length> bytes from the specified C<fh> and C<offset>
110into the scalar given by C<data> and offset C<dataoffset> and calls the
111callback without the actual number of bytes read (or C<undef> on error).
112
113=item aio_stat $fh_or_path, $callback
114
115=item aio_lstat $fh, $callback
116
117Works like perl's C<stat> or C<lstat> in void context. The callback will
118be called after the stat and the results will be available using C<stat _>
119or C<-s _> etc...
120
121Currently, the stats are always 64-bit-stats, i.e. instead of returning an
122error when stat'ing a large file, the results will be silently truncated
123unless perl itself is compiled with large file support.
124
125=item aio_unlink $pathname, $callback
126
127Asynchronously unlink a file.
128
71=cut 129=cut
130
131min_parallel 1;
72 132
73END { 133END {
74 max_parallel 0; 134 max_parallel 0;
75} 135}
76 136
… …
78 138
79=back 139=back
80 140
81=head1 BUGS 141=head1 BUGS
82 142
83This module has not yet been extensively tested. Watch out! 143This module has been extensively tested in a large and very busy webserver
144for many years now.
145
146 - aio_open gives a fd, but all other functions expect a perl filehandle.
84 147
85=head1 SEE ALSO 148=head1 SEE ALSO
86 149
87L<Coro>. 150L<Coro>.
88 151
89=head1 AUTHOR 152=head1 AUTHOR
90 153
91 Marc Lehmann <pcg@goof.com> 154 Marc Lehmann <schmorp@schmorp.de>
92 http://www.goof.com/pcg/marc/ 155 http://home.schmorp.de/
93 156
94=cut 157=cut
95 158

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