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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.5 by root, Sun Jul 10 21:04:24 2005 UTC vs.
Revision 1.22 by root, Wed Jul 20 21:55:27 2005 UTC

… …
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub {
10 my ($fh) = @_;
11 ...
12 };
13
14 aio_unlink "/tmp/file", sub { };
15
16 aio_read $fh, 30000, 1024, $buffer, 0, sub {
17 $_[0] > 0 or die "read error: $!";
18 };
19
20 # Event
21 Event->io (fd => IO::AIO::poll_fileno,
22 poll => 'r',
23 cb => \&IO::AIO::poll_cb);
24
25 # Glib/Gtk2
26 add_watch Glib::IO IO::AIO::poll_fileno,
27 in => sub { IO::AIO::poll_cb; 1 };
28
29 # Tk
30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
31 readable => \&IO::AIO::poll_cb);
32
33 # Danga::Socket
34 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
35 \&IO::AIO::poll_cb);
36
8 37
9=head1 DESCRIPTION 38=head1 DESCRIPTION
10 39
11This module implements asynchronous I/O using whatever means your 40This module implements asynchronous I/O using whatever means your
12operating system supports. 41operating system supports.
… …
19not well-supported (Linux doesn't allow them on normal files currently, 48not well-supported (Linux doesn't allow them on normal files currently,
20for example), and they would only support aio_read and aio_write, so the 49for example), and they would only support aio_read and aio_write, so the
21remaining functionality would have to be implemented using threads anyway. 50remaining functionality would have to be implemented using threads anyway.
22 51
23Although the module will work with in the presence of other threads, it is 52Although the module will work with in the presence of other threads, it is
24currently not reentrant, so use appropriate locking yourself. 53currently not reentrant, so use appropriate locking yourself, always call
54C<poll_cb> from within the same thread, or never call C<poll_cb> (or other
55C<aio_> functions) recursively.
25 56
26=cut 57=cut
27 58
28package IO::AIO; 59package IO::AIO;
29 60
30use base 'Exporter'; 61use base 'Exporter';
31 62
32use Fcntl (); 63use Fcntl ();
33 64
34BEGIN { 65BEGIN {
35 $VERSION = 0.2; 66 $VERSION = 0.9;
36 67
37 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 68 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
38 aio_fsync aio_fdatasync aio_readahead); 69 aio_fsync aio_fdatasync aio_readahead);
39 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 70 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
40 71
… …
46 77
47=head2 AIO FUNCTIONS 78=head2 AIO FUNCTIONS
48 79
49All the C<aio_*> calls are more or less thin wrappers around the syscall 80All the C<aio_*> calls are more or less thin wrappers around the syscall
50with the same name (sans C<aio_>). The arguments are similar or identical, 81with the same name (sans C<aio_>). The arguments are similar or identical,
51and they all accept an additional C<$callback> argument which must be 82and they all accept an additional (and optional) C<$callback> argument
52a code reference. This code reference will get called with the syscall 83which must be a code reference. This code reference will get called with
53return code (e.g. most syscalls return C<-1> on error, unlike perl, which 84the syscall return code (e.g. most syscalls return C<-1> on error, unlike
54usually delivers "false") as it's sole argument when the given syscall has 85perl, which usually delivers "false") as it's sole argument when the given
55been executed asynchronously. 86syscall has been executed asynchronously.
56 87
57All functions that expect a filehandle will also accept a file descriptor. 88All functions that expect a filehandle will also accept a file descriptor.
58 89
59The filenames you pass to these routines I<must> be absolute. The reason 90The filenames you pass to these routines I<must> be absolute. The reason
60is that at the time the request is being executed, the current working 91for this is that at the time the request is being executed, the current
61directory could have changed. Alternatively, you can make sure that you 92working directory could have changed. Alternatively, you can make sure
62never change the current working directory. 93that you never change the current working directory.
63 94
64=over 4 95=over 4
65 96
66=item aio_open $pathname, $flags, $mode, $callback 97=item aio_open $pathname, $flags, $mode, $callback
67 98
… …
69created filehandle for the file. 100created filehandle for the file.
70 101
71The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 102The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
72for an explanation. 103for an explanation.
73 104
74The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 105The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
75list. They are the same as used in C<sysopen>. 106list. They are the same as used by C<sysopen>.
107
108Likewise, C<$mode> specifies the mode of the newly created file, if it
109didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
110except that it is mandatory (i.e. use C<0> if you don't create new files,
111and C<0666> or C<0777> if you do).
76 112
77Example: 113Example:
78 114
79 aio_open "/etc/passwd", O_RDONLY, 0, sub { 115 aio_open "/etc/passwd", O_RDONLY, 0, sub {
80 if ($_[0]) { 116 if ($_[0]) {
… …
87 123
88=item aio_close $fh, $callback 124=item aio_close $fh, $callback
89 125
90Asynchronously close a file and call the callback with the result 126Asynchronously close a file and call the callback with the result
91code. I<WARNING:> although accepted, you should not pass in a perl 127code. I<WARNING:> although accepted, you should not pass in a perl
92filehandle here, as perl will likely close the file descriptor itself when 128filehandle here, as perl will likely close the file descriptor another
93the filehandle is destroyed. Normally, you can safely call perls C<close> 129time when the filehandle is destroyed. Normally, you can safely call perls
94or just let filehandles go out of scope. 130C<close> or just let filehandles go out of scope.
131
132This is supposed to be a bug in the API, so that might change. It's
133therefore best to avoid this function.
95 134
96=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 135=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
97 136
98=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 137=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
99 138
100Reads or writes C<length> bytes from the specified C<fh> and C<offset> 139Reads or writes C<length> bytes from the specified C<fh> and C<offset>
101into the scalar given by C<data> and offset C<dataoffset> and calls the 140into the scalar given by C<data> and offset C<dataoffset> and calls the
102callback without the actual number of bytes read (or -1 on error, just 141callback without the actual number of bytes read (or -1 on error, just
103like the syscall). 142like the syscall).
104 143
105Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 144Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
106offset C<0> within the scalar: 145offset C<0> within the scalar:
107 146
108 aio_read $fh, 7, 15, $buffer, 0, sub { 147 aio_read $fh, 7, 15, $buffer, 0, sub {
109 $_[0] >= 0 or die "read error: $!"; 148 $_[0] > 0 or die "read error: $!";
110 print "read <$buffer>\n"; 149 print "read $_[0] bytes: <$buffer>\n";
111 }; 150 };
112 151
113=item aio_readahead $fh,$offset,$length, $callback 152=item aio_readahead $fh,$offset,$length, $callback
114 153
115Asynchronously reads the specified byte range into the page cache, using 154Asynchronously reads the specified byte range into the page cache, using
116the C<readahead> syscall. If that syscall doesn't exist the status will be 155the C<readahead> syscall. If that syscall doesn't exist (likely if your OS
117C<-1> and C<$!> is set to ENOSYS. 156isn't Linux) the status will be C<-1> and C<$!> is set to C<ENOSYS>.
118 157
119readahead() populates the page cache with data from a file so that 158C<aio_readahead> populates the page cache with data from a file so that
120subsequent reads from that file will not block on disk I/O. The C<$offset> 159subsequent reads from that file will not block on disk I/O. The C<$offset>
121argument specifies the starting point from which data is to be read and 160argument specifies the starting point from which data is to be read and
122C<$length> specifies the number of bytes to be read. I/O is performed in 161C<$length> specifies the number of bytes to be read. I/O is performed in
123whole pages, so that offset is effectively rounded down to a page boundary 162whole pages, so that offset is effectively rounded down to a page boundary
124and bytes are read up to the next page boundary greater than or equal to 163and bytes are read up to the next page boundary greater than or equal to
125(off-set+length). aio_readahead() does not read beyond the end of the 164(off-set+length). C<aio_readahead> does not read beyond the end of the
126file. The current file offset of the file is left unchanged. 165file. The current file offset of the file is left unchanged.
127 166
128=item aio_stat $fh_or_path, $callback 167=item aio_stat $fh_or_path, $callback
129 168
130=item aio_lstat $fh, $callback 169=item aio_lstat $fh, $callback
… …
158with the fsync result code. 197with the fsync result code.
159 198
160=item aio_fdatasync $fh, $callback 199=item aio_fdatasync $fh, $callback
161 200
162Asynchronously call fdatasync on the given filehandle and call the 201Asynchronously call fdatasync on the given filehandle and call the
163callback with the fdatasync result code. 202callback with the fdatasync result code. Might set C<$!> to C<ENOSYS> if
203C<fdatasync> is not available.
164 204
165=back 205=back
166 206
167=head2 SUPPORT FUNCTIONS 207=head2 SUPPORT FUNCTIONS
168 208
169=over 4 209=over 4
170 210
171=item $fileno = IO::AIO::poll_fileno 211=item $fileno = IO::AIO::poll_fileno
172 212
173Return the I<request result pipe filehandle>. This filehandle must be 213Return the I<request result pipe file descriptor>. This filehandle must be
174polled for reading by some mechanism outside this module (e.g. Event 214polled for reading by some mechanism outside this module (e.g. Event or
175or select, see below). If the pipe becomes readable you have to call 215select, see below or the SYNOPSIS). If the pipe becomes readable you have
176C<poll_cb> to check the results. 216to call C<poll_cb> to check the results.
177 217
178See C<poll_cb> for an example. 218See C<poll_cb> for an example.
179 219
180=item IO::AIO::poll_cb 220=item IO::AIO::poll_cb
181 221
182Process all outstanding events on the result pipe. You have to call this 222Process all outstanding events on the result pipe. You have to call this
183regularly. Returns the number of events processed. Returns immediately 223regularly. Returns the number of events processed. Returns immediately
184when no events are outstanding. 224when no events are outstanding.
185 225
186You can use Event to multiplex, e.g.: 226Example: Install an Event watcher that automatically calls
227IO::AIO::poll_cb with high priority:
187 228
188 Event->io (fd => IO::AIO::poll_fileno, 229 Event->io (fd => IO::AIO::poll_fileno,
189 poll => 'r', async => 1, 230 poll => 'r', async => 1,
190 cb => \&IO::AIO::poll_cb); 231 cb => \&IO::AIO::poll_cb);
191 232
192=item IO::AIO::poll_wait 233=item IO::AIO::poll_wait
193 234
194Wait till the result filehandle becomes ready for reading (simply does a 235Wait till the result filehandle becomes ready for reading (simply does a
195select on the filehandle. This is useful if you want to synchronously wait 236C<select> on the filehandle. This is useful if you want to synchronously wait
196for some requests to finish). 237for some requests to finish).
197 238
198See C<nreqs> for an example. 239See C<nreqs> for an example.
199 240
200=item IO::AIO::nreqs 241=item IO::AIO::nreqs
201 242
202Returns the number of requests currently outstanding. 243Returns the number of requests currently outstanding (i.e. for which their
244callback has not been invoked yet).
203 245
204Example: wait till there are no outstanding requests anymore: 246Example: wait till there are no outstanding requests anymore:
205 247
206 IO::AIO::poll_wait, IO::AIO::poll_cb 248 IO::AIO::poll_wait, IO::AIO::poll_cb
207 while IO::AIO::nreqs; 249 while IO::AIO::nreqs;
250
251=item IO::AIO::flush
252
253Wait till all outstanding AIO requests have been handled.
254
255Strictly equivalent to:
256
257 IO::AIO::poll_wait, IO::AIO::poll_cb
258 while IO::AIO::nreqs;
259
260=item IO::AIO::poll
261
262Waits until some requests have been handled.
263
264Strictly equivalent to:
265
266 IO::AIO::poll_wait, IO::AIO::poll_cb
267 if IO::AIO::nreqs;
208 268
209=item IO::AIO::min_parallel $nthreads 269=item IO::AIO::min_parallel $nthreads
210 270
211Set the minimum number of AIO threads to C<$nthreads>. The default is 271Set the minimum number of AIO threads to C<$nthreads>. The default is
212C<1>, which means a single asynchronous operation can be done at one time 272C<1>, which means a single asynchronous operation can be done at one time

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