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Comparing Linux-AIO/AIO.pm (file contents):
Revision 1.7 by root, Mon Oct 8 12:58:41 2001 UTC vs.
Revision 1.29 by root, Sat Jul 9 22:45:05 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 = 0.01; 38 $VERSION = 1.7;
27 39
28 @EXPORT = qw(aio_read aio_write aio_open aio_close); 40 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
41 aio_fsync aio_fdatasync aio_readahead);
29 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs); 42 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs);
30 43
31 require XSLoader; 44 require XSLoader;
32 XSLoader::load Linux::AIO, $VERSION; 45 XSLoader::load Linux::AIO, $VERSION;
33} 46}
34 47
35=item Linux::AIO::min_parallel($nthreads) 48=item Linux::AIO::min_parallel $nthreads
36 49
37Set the minimum number of AIO threads to $nthreads. You I<have> to call 50Set the minimum number of AIO threads to C<$nthreads>. The default is
38this function with a positive number at leats once, otherwise no threads 51C<1>, which means a single asynchronous operation can be done at one time
39will be started and you aio-operations will seem to hang. 52(the number of outstanding operations, however, is unlimited).
53
54It is recommended to keep the number of threads low, as some linux
55kernel versions will scale negatively with the number of threads (higher
56parallelity => MUCH higher latency).
57
58=item Linux::AIO::max_parallel $nthreads
59
60Sets the maximum number of AIO threads to C<$nthreads>. If more than
61the specified number of threads are currently running, kill them. This
62function blocks until the limit is reached.
63
64This module automatically runs C<max_parallel 0> at program end, to ensure
65that all threads are killed and that there are no outstanding requests.
40 66
41=item $fileno = Linux::AIO::poll_fileno 67=item $fileno = Linux::AIO::poll_fileno
42 68
43Return the request result pipe filehandle. This filehandle must be polled 69Return the I<request result pipe filehandle>. This filehandle must be
44for reading. If the pipe becomes readable you have to call C<poll_cb>. 70polled for reading by some mechanism outside this module (e.g. Event
71or select, see below). If the pipe becomes readable you have to call
72C<poll_cb> to check the results.
45 73
46=item Linux::AIO::poll_cb 74=item Linux::AIO::poll_cb
47 75
48Process all outstanding events on the result pipe. You have to call this 76Process all outstanding events on the result pipe. You have to call this
49regularly. Returns the number of events processed. 77regularly. Returns the number of events processed. Returns immediately
78when no events are outstanding.
50 79
51You can use Event to multiplex, e.g.: 80You can use Event to multiplex, e.g.:
52 81
53 Event->io(fd => Linux::AIO::poll_fileno, 82 Event->io (fd => Linux::AIO::poll_fileno,
54 poll => 'r', async => 1, 83 poll => 'r', async => 1,
55 cb => \&Linux::AIO::poll_cb ); 84 cb => \&Linux::AIO::poll_cb );
56 85
86=item Linux::AIO::poll_wait
87
88Wait till the result filehandle becomes ready for reading (simply does a
89select on the filehandle. This is useful if you want to synchronously wait
90for some requests to finish).
57 91
58=item Linux::AIO::nreqs 92=item Linux::AIO::nreqs
59 93
60Returns the number of requests currently outstanding. 94Returns the number of requests currently outstanding.
61 95
96=item aio_open $pathname, $flags, $mode, $callback
97
98Asynchronously open or create a file and call the callback with the
99filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this
100might change in the future).
101
102=item aio_close $fh, $callback
103
104Asynchronously close a file and call the callback with the result code.
105
62=item aio_read($fh,$offset,$length, $data,$dataoffset,$callback) 106=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
107
63aio_write($fh,$offset,$length, $data,$dataoffset,$callback) 108=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
64 109
65Reads or writes C<length> bytes from the specified C<fh> and C<offset> 110Reads or writes C<length> bytes from the specified C<fh> and C<offset>
66into the scalar given by C<data> and offset C<dataoffset> and calls the 111into the scalar given by C<data> and offset C<dataoffset> and calls the
67callback without the actual number of bytes read (or undef on error). 112callback without the actual number of bytes read (or C<undef> on error).
68 113
69=item aio_open($pathname, $flags, $mode, $callback) 114=item aio_stat $fh_or_path, $callback
70 115
71Asynchronously open or create a file and call the callback with the 116=item aio_lstat $fh, $callback
72filedescriptor.
73 117
74=item aio_close($fh, $callback) 118Works like perl's C<stat> or C<lstat> in void context. The callback will
119be called after the stat and the results will be available using C<stat _>
120or C<-s _> etc...
75 121
76Asynchronously close a file and call the callback with the result code. 122Currently, the stats are always 64-bit-stats, i.e. instead of returning an
123error when stat'ing a large file, the results will be silently truncated
124unless perl itself is compiled with large file support.
125
126=item aio_unlink $pathname, $callback
127
128Asynchronously unlink a file.
77 129
78=cut 130=cut
131
132min_parallel 1;
79 133
80END { 134END {
81 max_parallel 0; 135 max_parallel 0;
82} 136}
83 137
… …
85 139
86=back 140=back
87 141
88=head1 BUGS 142=head1 BUGS
89 143
90This module has not yet been extensively tested. Watch out! 144This module has been extensively tested in a large and very busy webserver
145for many years now.
91 146
92 - aio_stat/lstat are seriously missing here. 147 - aio_open gives a fd, but all other functions expect a perl filehandle.
93 148
94=head1 SEE ALSO 149=head1 SEE ALSO
95 150
96L<Coro>. 151L<Coro>.
97 152
98=head1 AUTHOR 153=head1 AUTHOR
99 154
100 Marc Lehmann <pcg@goof.com> 155 Marc Lehmann <schmorp@schmorp.de>
101 http://www.goof.com/pcg/marc/ 156 http://home.schmorp.de/
102 157
103=cut 158=cut
104 159

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