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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.5 by root, Sun Jul 10 21:04:24 2005 UTC vs.
Revision 1.26 by root, Sun Aug 7 03:34:07 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
61no warnings;
62
30use base 'Exporter'; 63use base 'Exporter';
31 64
32use Fcntl (); 65use Fcntl ();
33 66
34BEGIN { 67BEGIN {
35 $VERSION = 0.2; 68 $VERSION = 1.1;
36 69
37 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 70 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
38 aio_fsync aio_fdatasync aio_readahead); 71 aio_fsync aio_fdatasync aio_readahead);
39 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 72 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
40 73
… …
46 79
47=head2 AIO FUNCTIONS 80=head2 AIO FUNCTIONS
48 81
49All the C<aio_*> calls are more or less thin wrappers around the syscall 82All the C<aio_*> calls are more or less thin wrappers around the syscall
50with the same name (sans C<aio_>). The arguments are similar or identical, 83with the same name (sans C<aio_>). The arguments are similar or identical,
51and they all accept an additional C<$callback> argument which must be 84and they all accept an additional (and optional) C<$callback> argument
52a code reference. This code reference will get called with the syscall 85which 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 86the 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 87perl, which usually delivers "false") as it's sole argument when the given
55been executed asynchronously. 88syscall has been executed asynchronously.
56 89
57All functions that expect a filehandle will also accept a file descriptor. 90All functions expecting a filehandle keep a copy of the filehandle
91internally until the request has finished.
58 92
59The filenames you pass to these routines I<must> be absolute. The reason 93The 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 94for this is that at the time the request is being executed, the current
61directory could have changed. Alternatively, you can make sure that you 95working directory could have changed. Alternatively, you can make sure
62never change the current working directory. 96that you never change the current working directory.
63 97
64=over 4 98=over 4
65 99
66=item aio_open $pathname, $flags, $mode, $callback 100=item aio_open $pathname, $flags, $mode, $callback
67 101
… …
69created filehandle for the file. 103created filehandle for the file.
70 104
71The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 105The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
72for an explanation. 106for an explanation.
73 107
74The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 108The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
75list. They are the same as used in C<sysopen>. 109list. They are the same as used by C<sysopen>.
110
111Likewise, C<$mode> specifies the mode of the newly created file, if it
112didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
113except that it is mandatory (i.e. use C<0> if you don't create new files,
114and C<0666> or C<0777> if you do).
76 115
77Example: 116Example:
78 117
79 aio_open "/etc/passwd", O_RDONLY, 0, sub { 118 aio_open "/etc/passwd", O_RDONLY, 0, sub {
80 if ($_[0]) { 119 if ($_[0]) {
… …
87 126
88=item aio_close $fh, $callback 127=item aio_close $fh, $callback
89 128
90Asynchronously close a file and call the callback with the result 129Asynchronously close a file and call the callback with the result
91code. I<WARNING:> although accepted, you should not pass in a perl 130code. I<WARNING:> although accepted, you should not pass in a perl
92filehandle here, as perl will likely close the file descriptor itself when 131filehandle here, as perl will likely close the file descriptor another
93the filehandle is destroyed. Normally, you can safely call perls C<close> 132time when the filehandle is destroyed. Normally, you can safely call perls
94or just let filehandles go out of scope. 133C<close> or just let filehandles go out of scope.
134
135This is supposed to be a bug in the API, so that might change. It's
136therefore best to avoid this function.
95 137
96=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 138=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
97 139
98=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 140=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
99 141
100Reads or writes C<length> bytes from the specified C<fh> and C<offset> 142Reads or writes C<length> bytes from the specified C<fh> and C<offset>
101into the scalar given by C<data> and offset C<dataoffset> and calls the 143into the scalar given by C<data> and offset C<dataoffset> and calls the
102callback without the actual number of bytes read (or -1 on error, just 144callback without the actual number of bytes read (or -1 on error, just
103like the syscall). 145like the syscall).
104 146
105Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 147Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
106offset C<0> within the scalar: 148offset C<0> within the scalar:
107 149
108 aio_read $fh, 7, 15, $buffer, 0, sub { 150 aio_read $fh, 7, 15, $buffer, 0, sub {
109 $_[0] >= 0 or die "read error: $!"; 151 $_[0] > 0 or die "read error: $!";
110 print "read <$buffer>\n"; 152 print "read $_[0] bytes: <$buffer>\n";
111 }; 153 };
112 154
113=item aio_readahead $fh,$offset,$length, $callback 155=item aio_readahead $fh,$offset,$length, $callback
114 156
115Asynchronously reads the specified byte range into the page cache, using
116the C<readahead> syscall. If that syscall doesn't exist the status will be
117C<-1> and C<$!> is set to ENOSYS.
118
119readahead() populates the page cache with data from a file so that 157C<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<$offset> 158subsequent reads from that file will not block on disk I/O. The C<$offset>
121argument specifies the starting point from which data is to be read and 159argument specifies the starting point from which data is to be read and
122C<$length> specifies the number of bytes to be read. I/O is performed in 160C<$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 161whole 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 162and 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 163(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. 164file. The current file offset of the file is left unchanged.
165
166If that syscall doesn't exist (likely if your OS isn't Linux) it will be
167emulated by simply reading the data, which would have a similar effect.
127 168
128=item aio_stat $fh_or_path, $callback 169=item aio_stat $fh_or_path, $callback
129 170
130=item aio_lstat $fh, $callback 171=item aio_lstat $fh, $callback
131 172
… …
160=item aio_fdatasync $fh, $callback 201=item aio_fdatasync $fh, $callback
161 202
162Asynchronously call fdatasync on the given filehandle and call the 203Asynchronously call fdatasync on the given filehandle and call the
163callback with the fdatasync result code. 204callback with the fdatasync result code.
164 205
206If this call isn't available because your OS lacks it or it couldn't be
207detected, it will be emulated by calling C<fsync> instead.
208
165=back 209=back
166 210
167=head2 SUPPORT FUNCTIONS 211=head2 SUPPORT FUNCTIONS
168 212
169=over 4 213=over 4
170 214
171=item $fileno = IO::AIO::poll_fileno 215=item $fileno = IO::AIO::poll_fileno
172 216
173Return the I<request result pipe filehandle>. This filehandle must be 217Return the I<request result pipe file descriptor>. This filehandle must be
174polled for reading by some mechanism outside this module (e.g. Event 218polled 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 219select, see below or the SYNOPSIS). If the pipe becomes readable you have
176C<poll_cb> to check the results. 220to call C<poll_cb> to check the results.
177 221
178See C<poll_cb> for an example. 222See C<poll_cb> for an example.
179 223
180=item IO::AIO::poll_cb 224=item IO::AIO::poll_cb
181 225
182Process all outstanding events on the result pipe. You have to call this 226Process all outstanding events on the result pipe. You have to call this
183regularly. Returns the number of events processed. Returns immediately 227regularly. Returns the number of events processed. Returns immediately
184when no events are outstanding. 228when no events are outstanding.
185 229
186You can use Event to multiplex, e.g.: 230Example: Install an Event watcher that automatically calls
231IO::AIO::poll_cb with high priority:
187 232
188 Event->io (fd => IO::AIO::poll_fileno, 233 Event->io (fd => IO::AIO::poll_fileno,
189 poll => 'r', async => 1, 234 poll => 'r', async => 1,
190 cb => \&IO::AIO::poll_cb); 235 cb => \&IO::AIO::poll_cb);
191 236
192=item IO::AIO::poll_wait 237=item IO::AIO::poll_wait
193 238
194Wait till the result filehandle becomes ready for reading (simply does a 239Wait till the result filehandle becomes ready for reading (simply does a
195select on the filehandle. This is useful if you want to synchronously wait 240C<select> on the filehandle. This is useful if you want to synchronously wait
196for some requests to finish). 241for some requests to finish).
197 242
198See C<nreqs> for an example. 243See C<nreqs> for an example.
199 244
200=item IO::AIO::nreqs 245=item IO::AIO::nreqs
201 246
202Returns the number of requests currently outstanding. 247Returns the number of requests currently outstanding (i.e. for which their
248callback has not been invoked yet).
203 249
204Example: wait till there are no outstanding requests anymore: 250Example: wait till there are no outstanding requests anymore:
205 251
206 IO::AIO::poll_wait, IO::AIO::poll_cb 252 IO::AIO::poll_wait, IO::AIO::poll_cb
207 while IO::AIO::nreqs; 253 while IO::AIO::nreqs;
254
255=item IO::AIO::flush
256
257Wait till all outstanding AIO requests have been handled.
258
259Strictly equivalent to:
260
261 IO::AIO::poll_wait, IO::AIO::poll_cb
262 while IO::AIO::nreqs;
263
264=item IO::AIO::poll
265
266Waits until some requests have been handled.
267
268Strictly equivalent to:
269
270 IO::AIO::poll_wait, IO::AIO::poll_cb
271 if IO::AIO::nreqs;
208 272
209=item IO::AIO::min_parallel $nthreads 273=item IO::AIO::min_parallel $nthreads
210 274
211Set the minimum number of AIO threads to C<$nthreads>. The default is 275Set 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 276C<1>, which means a single asynchronous operation can be done at one time
… …
250 314
251# support function to convert a fd into a perl filehandle 315# support function to convert a fd into a perl filehandle
252sub _fd2fh { 316sub _fd2fh {
253 return undef if $_[0] < 0; 317 return undef if $_[0] < 0;
254 318
255 # try to be perl5.6-compatible 319 # try to generate nice filehandles
256 local *AIO_FH; 320 my $sym = "IO::AIO::fd#$_[0]";
257 open AIO_FH, "+<&=$_[0]" 321 local *$sym;
322
323 open *$sym, "+<&$_[0]" # usually under any unix
324 or open *$sym, "<&$_[0]" # cygwin needs this
325 or open *$sym, ">&$_[0]" # cygwin needs this
258 or return undef; 326 or return undef;
259 327
260 *AIO_FH 328 *$sym
261} 329}
262 330
263min_parallel 4; 331min_parallel 4;
264 332
265END { 333END {

Diff Legend

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