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Revision 1.151 by root, Fri Jun 12 00:43:16 2009 UTC vs.
Revision 1.157 by root, Wed Jun 17 01:14:48 2009 UTC

30 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) 31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO; 32 use AnyEvent::AIO;
33 33
34 # EV integration 34 # EV integration
35 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 35 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36 36
37 # Event integration 37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno, 38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r', 39 poll => 'r',
40 cb => \&IO::AIO::poll_cb); 40 cb => \&IO::AIO::poll_cb);
52 \&IO::AIO::poll_cb); 52 \&IO::AIO::poll_cb);
53 53
54=head1 DESCRIPTION 54=head1 DESCRIPTION
55 55
56This module implements asynchronous I/O using whatever means your 56This module implements asynchronous I/O using whatever means your
57operating system supports. 57operating system supports. It is implemented as an interface to C<libeio>
58(L<http://software.schmorp.de/pkg/libeio.html>).
58 59
59Asynchronous means that operations that can normally block your program 60Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation 61(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This 62will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even 63is extremely useful for programs that need to stay interactive even
66on a RAID volume or over NFS when you do a number of stat operations 67on a RAID volume or over NFS when you do a number of stat operations
67concurrently. 68concurrently.
68 69
69While most of this works on all types of file descriptors (for 70While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that 71example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very 72support nonblocking operation (again, sockets, pipes etc.) is
72inefficient. Use an event loop for that (such as the L<Event|Event> 73very inefficient. Use an event loop for that (such as the L<EV>
73module): IO::AIO will naturally fit into such an event loop itself. 74module): IO::AIO will naturally fit into such an event loop itself.
74 75
75In this version, a number of threads are started that execute your 76In this version, a number of threads are started that execute your
76requests and signal their completion. You don't need thread support 77requests and signal their completion. You don't need thread support
77in perl, and the threads created by this module will not be visible 78in perl, and the threads created by this module will not be visible
87yourself, always call C<poll_cb> from within the same thread, or never 88yourself, always call C<poll_cb> from within the same thread, or never
88call C<poll_cb> (or other C<aio_> functions) recursively. 89call C<poll_cb> (or other C<aio_> functions) recursively.
89 90
90=head2 EXAMPLE 91=head2 EXAMPLE
91 92
92This is a simple example that uses the Event module and loads 93This is a simple example that uses the EV module and loads
93F</etc/passwd> asynchronously: 94F</etc/passwd> asynchronously:
94 95
95 use Fcntl; 96 use Fcntl;
96 use Event; 97 use EV;
97 use IO::AIO; 98 use IO::AIO;
98 99
99 # register the IO::AIO callback with Event 100 # register the IO::AIO callback with EV
100 Event->io (fd => IO::AIO::poll_fileno, 101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103 102
104 # queue the request to open /etc/passwd 103 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub { 104 aio_open "/etc/passwd", O_RDONLY, 0, sub {
106 my $fh = shift 105 my $fh = shift
107 or die "error while opening: $!"; 106 or die "error while opening: $!";
119 118
120 # file contents now in $contents 119 # file contents now in $contents
121 print $contents; 120 print $contents;
122 121
123 # exit event loop and program 122 # exit event loop and program
124 Event::unloop; 123 EV::unloop;
125 }; 124 };
126 }; 125 };
127 126
128 # possibly queue up other requests, or open GUI windows, 127 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc. 128 # check for sockets etc. etc.
130 129
131 # process events as long as there are some: 130 # process events as long as there are some:
132 Event::loop; 131 EV::loop;
133 132
134=head1 REQUEST ANATOMY AND LIFETIME 133=head1 REQUEST ANATOMY AND LIFETIME
135 134
136Every C<aio_*> function creates a request. which is a C data structure not 135Every C<aio_*> function creates a request. which is a C data structure not
137directly visible to Perl. 136directly visible to Perl.
193use strict 'vars'; 192use strict 'vars';
194 193
195use base 'Exporter'; 194use base 'Exporter';
196 195
197BEGIN { 196BEGIN {
198 our $VERSION = '3.2'; 197 our $VERSION = '3.23';
199 198
200 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 199 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
201 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 200 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 201 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
203 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 202 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
207 206
208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210 min_parallel max_parallel max_idle 209 min_parallel max_parallel max_idle
211 nreqs nready npending nthreads 210 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs); 211 max_poll_time max_poll_reqs
212 sendfile fadvise);
213 213
214 push @AIO_REQ, qw(aio_busy); # not exported 214 push @AIO_REQ, qw(aio_busy); # not exported
215 215
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 217
568C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 568C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
569know, you have to run stat yourself. Also, for speed reasons, the C<$type> 569know, you have to run stat yourself. Also, for speed reasons, the C<$type>
570scalars are read-only: you can not modify them. 570scalars are read-only: you can not modify them.
571 571
572C<$inode> is the inode number (which might not be exact on systems with 64 572C<$inode> is the inode number (which might not be exact on systems with 64
573bit inode numbers and 32 bit perls). On systems that do not deliver the 573bit inode numbers and 32 bit perls). This field has unspecified content on
574inode information, this will always be zero. 574systems that do not deliver the inode information.
575 575
576=item IO::AIO::READDIR_DIRS_FIRST 576=item IO::AIO::READDIR_DIRS_FIRST
577 577
578When this flag is set, then the names will be returned in an order where 578When this flag is set, then the names will be returned in an order where
579likely directories come first. This is useful when you need to quickly 579likely directories come first. This is useful when you need to quickly
1208=over 4 1208=over 4
1209 1209
1210=item $fileno = IO::AIO::poll_fileno 1210=item $fileno = IO::AIO::poll_fileno
1211 1211
1212Return the I<request result pipe file descriptor>. This filehandle must be 1212Return the I<request result pipe file descriptor>. This filehandle must be
1213polled for reading by some mechanism outside this module (e.g. Event or 1213polled for reading by some mechanism outside this module (e.g. EV, Glib,
1214select, see below or the SYNOPSIS). If the pipe becomes readable you have 1214select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1215to call C<poll_cb> to check the results. 1215you have to call C<poll_cb> to check the results.
1216 1216
1217See C<poll_cb> for an example. 1217See C<poll_cb> for an example.
1218 1218
1219=item IO::AIO::poll_cb 1219=item IO::AIO::poll_cb
1220 1220
1227If not all requests were processed for whatever reason, the filehandle 1227If not all requests were processed for whatever reason, the filehandle
1228will still be ready when C<poll_cb> returns, so normally you don't have to 1228will still be ready when C<poll_cb> returns, so normally you don't have to
1229do anything special to have it called later. 1229do anything special to have it called later.
1230 1230
1231Example: Install an Event watcher that automatically calls 1231Example: Install an Event watcher that automatically calls
1232IO::AIO::poll_cb with high priority: 1232IO::AIO::poll_cb with high priority (more examples can be found in the
1233SYNOPSIS section, at the top of this document):
1233 1234
1234 Event->io (fd => IO::AIO::poll_fileno, 1235 Event->io (fd => IO::AIO::poll_fileno,
1235 poll => 'r', async => 1, 1236 poll => 'r', async => 1,
1236 cb => \&IO::AIO::poll_cb); 1237 cb => \&IO::AIO::poll_cb);
1237 1238
1391 1392
1392=item IO::AIO::npending 1393=item IO::AIO::npending
1393 1394
1394Returns the number of requests currently in the pending state (executed, 1395Returns the number of requests currently in the pending state (executed,
1395but not yet processed by poll_cb). 1396but not yet processed by poll_cb).
1397
1398=back
1399
1400=head3 MISCELLANEOUS FUNCTIONS
1401
1402IO::AIO implements some functions that might be useful, but are not
1403asynchronous.
1404
1405=over 4
1406
1407=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1408
1409Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1410but is blocking (this makes most sense if you know the input data is
1411likely cached already and the output filehandle is set to non-blocking
1412operations).
1413
1414Returns the number of bytes copied, or C<-1> on error.
1415
1416=item IO::AIO::fadvise $fh, $offset, $len, $advice
1417
1418Simply calls the C<posix_fadvise> function (see it's
1419manpage for details). The following advice constants are
1420avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1421C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1422C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1423
1424On systems that do not implement C<posix_fadvise>, this function returns
1425ENOSYS, otherwise the return value of C<posix_fadvise>.
1396 1426
1397=back 1427=back
1398 1428
1399=cut 1429=cut
1400 1430

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