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Revision 1.88 by root, Sun Oct 29 01:50:29 2006 UTC vs.
Revision 1.91 by root, Mon Oct 30 23:30:29 2006 UTC

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61etc.), but can also be used to easily do operations in parallel that are 61etc.), but can also be used to easily do operations in parallel that are
62normally done sequentially, e.g. stat'ing many files, which is much faster 62normally done sequentially, e.g. stat'ing many files, which is much faster
63on a RAID volume or over NFS when you do a number of stat operations 63on a RAID volume or over NFS when you do a number of stat operations
64concurrently. 64concurrently.
65 65
66While this works on all types of file descriptors (for example sockets), 66While most of this works on all types of file descriptors (for example
67using these functions on file descriptors that support nonblocking 67sockets), using these functions on file descriptors that support
68operation (again, sockets, pipes etc.) is very inefficient. Use an event 68nonblocking operation (again, sockets, pipes etc.) is very inefficient or
69might not work (aio_read fails on sockets/pipes/fifos). Use an event loop
69loop for that (such as the L<Event|Event> module): IO::AIO will naturally 70for that (such as the L<Event|Event> module): IO::AIO will naturally fit
70fit into such an event loop itself. 71into such an event loop itself.
71 72
72In this version, a number of threads are started that execute your 73In this version, a number of threads are started that execute your
73requests and signal their completion. You don't need thread support 74requests and signal their completion. You don't need thread support
74in perl, and the threads created by this module will not be visible 75in perl, and the threads created by this module will not be visible
75to perl. In the future, this module might make use of the native aio 76to perl. In the future, this module might make use of the native aio
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188use strict 'vars'; 189use strict 'vars';
189 190
190use base 'Exporter'; 191use base 'Exporter';
191 192
192BEGIN { 193BEGIN {
193 our $VERSION = '2.1'; 194 our $VERSION = '2.2';
194 195
195 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 196 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
196 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 197 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
197 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 198 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
198 aio_copy aio_group aio_nop aio_mknod); 199 aio_move aio_copy aio_group aio_nop aio_mknod);
199 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 200 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
200 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 201 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
201 min_parallel max_parallel max_idle 202 min_parallel max_parallel max_idle
202 nreqs nready npending nthreads 203 nreqs nready npending nthreads
203 max_poll_time max_poll_reqs); 204 max_poll_time max_poll_reqs);
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416 417
417=item aio_symlink $srcpath, $dstpath, $callback->($status) 418=item aio_symlink $srcpath, $dstpath, $callback->($status)
418 419
419Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 420Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
420the path C<$dstpath> and call the callback with the result code. 421the path C<$dstpath> and call the callback with the result code.
422
423=item aio_readlink $path, $callback->($link)
424
425Asynchronously read the symlink specified by C<$path> and pass it to
426the callback. If an error occurs, nothing or undef gets passed to the
427callback.
421 428
422=item aio_rename $srcpath, $dstpath, $callback->($status) 429=item aio_rename $srcpath, $dstpath, $callback->($status)
423 430
424Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 431Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
425rename(2) and call the callback with the result code. 432rename(2) and call the callback with the result code.
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939that are being processed by C<IO::AIO::poll_cb> in one call, respectively 946that are being processed by C<IO::AIO::poll_cb> in one call, respectively
940the maximum amount of time (default C<0>, meaning infinity) spent in 947the maximum amount of time (default C<0>, meaning infinity) spent in
941C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount 948C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
942of time C<poll_cb> is allowed to use). 949of time C<poll_cb> is allowed to use).
943 950
951Setting C<max_poll_time> to a non-zero value creates an overhead of one
952syscall per request processed, which is not normally a problem unless your
953callbacks are really really fast or your OS is really really slow (I am
954not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
955
944Setting these is useful if you want to ensure some level of 956Setting these is useful if you want to ensure some level of
945interactiveness when perl is not fast enough to process all requests in 957interactiveness when perl is not fast enough to process all requests in
946time. 958time.
947 959
948For interactive programs, values such as C<0.01> to C<0.1> should be fine. 960For interactive programs, values such as C<0.01> to C<0.1> should be fine.
949 961
950Example: Install an Event watcher that automatically calls 962Example: Install an Event watcher that automatically calls
951IO::AIO::poll_some with low priority, to ensure that other parts of the 963IO::AIO::poll_cb with low priority, to ensure that other parts of the
952program get the CPU sometimes even under high AIO load. 964program get the CPU sometimes even under high AIO load.
953 965
954 # try not to spend much more than 0.1s in poll_cb 966 # try not to spend much more than 0.1s in poll_cb
955 IO::AIO::max_poll_time 0.1; 967 IO::AIO::max_poll_time 0.1;
956 968

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