ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/Linux-AIO/AIO.pm
(Generate patch)

Comparing Linux-AIO/AIO.pm (file contents):
Revision 1.27 by root, Fri Jul 8 02:43:47 2005 UTC vs.
Revision 1.35 by root, Tue Jul 12 10:51:09 2005 UTC

… …
24min_parallel from the same thread that loaded this module. 24min_parallel from the same thread that loaded this module.
25 25
26Although the module will work with in the presence of other threads, it is 26Although the module will work with in the presence of other threads, it is
27not reentrant, so use appropriate locking yourself. 27not reentrant, so use appropriate locking yourself.
28 28
29=head2 API NOTES
30
31All the C<aio_*> calls are more or less thin wrappers around the syscall
32with the same name (sans C<aio_>). The arguments are similar or identical,
33and they all accept an additional C<$callback> argument which must be
34a code reference. This code reference will get called with the syscall
35return code (e.g. most syscalls return C<-1> on error, unlike perl, which
36usually delivers "false") as it's sole argument when the given syscall has
37been executed asynchronously.
38
39All functions that expect a filehandle will also accept a file descriptor.
40
41The filenames you pass to these routines I<must> be absolute. The reason
42is that at the time the request is being executed, the current working
43directory could have changed. Alternatively, you can make sure that you
44never change the current working directory.
45
29=over 4 46=over 4
30 47
31=cut 48=cut
32 49
33package Linux::AIO; 50package Linux::AIO;
34 51
35use base 'Exporter'; 52use base 'Exporter';
36 53
37BEGIN { 54BEGIN {
38 $VERSION = 1.6; 55 $VERSION = 1.72;
39 56
40 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink); 57 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
58 aio_fsync aio_fdatasync aio_readahead);
41 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs); 59 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel nreqs);
42 60
43 require XSLoader; 61 require XSLoader;
44 XSLoader::load Linux::AIO, $VERSION; 62 XSLoader::load Linux::AIO, $VERSION;
45} 63}
… …
52 70
53It is recommended to keep the number of threads low, as some linux 71It is recommended to keep the number of threads low, as some linux
54kernel versions will scale negatively with the number of threads (higher 72kernel versions will scale negatively with the number of threads (higher
55parallelity => MUCH higher latency). 73parallelity => MUCH higher latency).
56 74
75Under normal circumstances you don't need to call this function, as this
76module automatically starts a single async thread.
77
57=item Linux::AIO::max_parallel $nthreads 78=item Linux::AIO::max_parallel $nthreads
58 79
59Sets the maximum number of AIO threads to C<$nthreads>. If more than 80Sets the maximum number of AIO threads to C<$nthreads>. If more than
60the specified number of threads are currently running, kill them. This 81the specified number of threads are currently running, kill them. This
61function blocks until the limit is reached. 82function blocks until the limit is reached.
62 83
63This module automatically runs C<max_parallel 0> at program end, to ensure 84This module automatically runs C<max_parallel 0> at program end, to ensure
64that all threads are killed and that there are no outstanding requests. 85that all threads are killed and that there are no outstanding requests.
86
87Under normal circumstances you don't need to call this function.
65 88
66=item $fileno = Linux::AIO::poll_fileno 89=item $fileno = Linux::AIO::poll_fileno
67 90
68Return the I<request result pipe filehandle>. This filehandle must be 91Return the I<request result pipe filehandle>. This filehandle must be
69polled for reading by some mechanism outside this module (e.g. Event 92polled for reading by some mechanism outside this module (e.g. Event
70or select, see below). If the pipe becomes readable you have to call 93or select, see below). If the pipe becomes readable you have to call
71C<poll_cb> to check the results. 94C<poll_cb> to check the results.
72 95
96See C<poll_cb> for an example.
97
73=item Linux::AIO::poll_cb 98=item Linux::AIO::poll_cb
74 99
75Process all outstanding events on the result pipe. You have to call this 100Process all outstanding events on the result pipe. You have to call this
76regularly. Returns the number of events processed. Returns immediately 101regularly. Returns the number of events processed. Returns immediately
77when no events are outstanding. 102when no events are outstanding.
78 103
79You can use Event to multiplex, e.g.: 104You can use Event to multiplex, e.g.:
80 105
81 Event->io (fd => Linux::AIO::poll_fileno, 106 Event->io (fd => Linux::AIO::poll_fileno,
82 poll => 'r', async => 1, 107 poll => 'r', async => 1,
83 cb => \&Linux::AIO::poll_cb ); 108 cb => \&Linux::AIO::poll_cb);
84 109
85=item Linux::AIO::poll_wait 110=item Linux::AIO::poll_wait
86 111
87Wait till the result filehandle becomes ready for reading (simply does a 112Wait till the result filehandle becomes ready for reading (simply does a
88select on the filehandle. This is useful if you want to synchronously wait 113select on the filehandle. This is useful if you want to synchronously wait
89for some requests to finish). 114for some requests to finish).
90 115
116See C<nreqs> for an example.
117
91=item Linux::AIO::nreqs 118=item Linux::AIO::nreqs
92 119
93Returns the number of requests currently outstanding. 120Returns the number of requests currently outstanding.
94 121
122Example: wait till there are no outstanding requests anymore:
123
124 Linux::AIO::poll_wait, Linux::AIO::poll_cb
125 while Linux::AIO::nreqs;
126
95=item aio_open $pathname, $flags, $mode, $callback 127=item aio_open $pathname, $flags, $mode, $callback
96 128
97Asynchronously open or create a file and call the callback with the 129Asynchronously open or create a file and call the callback with the
98filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this 130filedescriptor (NOT a perl filehandle, sorry for that, but watch out, this
99might change in the future). 131might change in the future).
100 132
133The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
134for an explanation.
135
136The C<$mode> argument is a bitmask. See the C<Fcntl> module for a
137list. They are the same as used in C<sysopen>.
138
139Example:
140
141 aio_open "/etc/passwd", O_RDONLY, 0, sub {
142 if ($_[0] >= 0) {
143 open my $fh, "<&=$_[0]";
144 print "open successful, fh is $fh\n";
145 ...
146 } else {
147 die "open failed: $!\n";
148 }
149 };
150
101=item aio_close $fh, $callback 151=item aio_close $fh, $callback
102 152
103Asynchronously close a file and call the callback with the result code. 153Asynchronously close a file and call the callback with the result code.
104 154
105=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 155=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
106 156
107=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 157=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
108 158
109Reads or writes C<length> bytes from the specified C<fh> and C<offset> 159Reads or writes C<length> bytes from the specified C<fh> and C<offset>
110into the scalar given by C<data> and offset C<dataoffset> and calls the 160into the scalar given by C<data> and offset C<dataoffset> and calls the
111callback without the actual number of bytes read (or C<undef> on error). 161callback without the actual number of bytes read (or -1 on error, just
162like the syscall).
163
164Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at
165offset C<0> within the scalar:
166
167 aio_read $fh, 7, 15, $buffer, 0, sub {
168 $_[0] >= 0 or die "read error: $!";
169 print "read <$buffer>\n";
170 };
171
172=item aio_readahead $fh,$offset,$length, $callback
173
174Asynchronously reads the specified byte range into the page cache, using
175the C<readahead> syscall.
176
177readahead() populates the page cache with data from a file so that
178subsequent reads from that file will not block on disk I/O. The C<$offset>
179argument specifies the starting point from which data is to be read and
180C<$length> specifies the number of bytes to be read. I/O is performed in
181whole pages, so that offset is effectively rounded down to a page boundary
182and bytes are read up to the next page boundary greater than or equal to
183(off-set+length). aio_readahead() does not read beyond the end of the
184file. The current file offset of the file is left unchanged.
112 185
113=item aio_stat $fh_or_path, $callback 186=item aio_stat $fh_or_path, $callback
114 187
115=item aio_lstat $fh, $callback 188=item aio_lstat $fh, $callback
116 189
117Works like perl's C<stat> or C<lstat> in void context. The callback will 190Works 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 _> 191be called after the stat and the results will be available using C<stat _>
119or C<-s _> etc... 192or C<-s _> etc...
120 193
194The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
195for an explanation.
196
121Currently, the stats are always 64-bit-stats, i.e. instead of returning an 197Currently, 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 198error when stat'ing a large file, the results will be silently truncated
123unless perl itself is compiled with large file support. 199unless perl itself is compiled with large file support.
124 200
201Example: Print the length of F</etc/passwd>:
202
203 aio_stat "/etc/passwd", sub {
204 $_[0] and die "stat failed: $!";
205 print "size is ", -s _, "\n";
206 };
207
125=item aio_unlink $pathname, $callback 208=item aio_unlink $pathname, $callback
126 209
127Asynchronously unlink a file. 210Asynchronously unlink (delete) a file and call the callback with the
211result code.
212
213=item aio_fsync $fh, $callback
214
215Asynchronously call fsync on the given filehandle and call the callback
216with the fsync result code.
217
218=item aio_fdatasync $fh, $callback
219
220Asynchronously call fdatasync on the given filehandle and call the
221callback with the fdatasync result code.
128 222
129=cut 223=cut
130 224
131min_parallel 1; 225min_parallel 1;
132 226
… …
145 239
146 - aio_open gives a fd, but all other functions expect a perl filehandle. 240 - aio_open gives a fd, but all other functions expect a perl filehandle.
147 241
148=head1 SEE ALSO 242=head1 SEE ALSO
149 243
150L<Coro>. 244L<Coro>, L<IO::AIO>.
151 245
152=head1 AUTHOR 246=head1 AUTHOR
153 247
154 Marc Lehmann <schmorp@schmorp.de> 248 Marc Lehmann <schmorp@schmorp.de>
155 http://home.schmorp.de/ 249 http://home.schmorp.de/

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines