[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.67 by root, Tue Oct 24 02:25:16 2006 UTC vs.
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC

  };
  # version 2+ has request and group objects
  use IO::AIO 2;
+ aioreq_pri 4; # give next request a very high priority
  my $req = aio_unlink "/tmp/file", sub { };
  $req->cancel; # cancel request if still in queue
  my $grp = aio_group sub { print "all stats done\n" };
  add $grp aio_stat "..." for ...;
 on many operating systems. However, they are often not well-supported
 (Linux doesn't allow them on normal files currently, for example),
 and they would only support aio_read and aio_write, so the remaining
 functionality would have to be implemented using threads anyway.
-Although the module will work with in the presence of other threads, it is
+Although the module will work with in the presence of other threads,
-currently not reentrant, so use appropriate locking yourself, always call
+it is currently not reentrant in any way, so use appropriate locking
-C<poll_cb> from within the same thread, or never call C<poll_cb> (or other
+yourself, always call C<poll_cb> from within the same thread, or never
-C<aio_> functions) recursively.
+call C<poll_cb> (or other C<aio_> functions) recursively.
 =cut
 package IO::AIO;
    our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
                      aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
                      aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
                      aio_group aio_nop);
-   our @EXPORT = (@AIO_REQ, qw(aioreq_pri));
+   our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
    our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
                        min_parallel max_parallel max_outstanding nreqs);
    @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
 environment, d) use Glib::filename_from_unicode on unicode filenames or e)
 use something else.
 =over 4
+=item aioreq_pri $pri
+Sets the priority for the next aio request. The default priority
+is C<0>, the minimum and maximum priorities are C<-4> and C<4>,
+respectively. Requests with higher priority will be serviced first.
+The priority will be reset to C<0> after each call to one of the C<aio_>
+functions.
+Example: open a file with low priority, then read something from it with
+higher priority so the read request is serviced before other low priority
+open requests (potentially spamming the cache):
+   aioreq_pri -3;
+   aio_open ..., sub {
+      return unless $_[0];
+      aioreq_pri -2;
+      aio_read $_[0], ..., sub {
+         ...
+      };
+   };
+=item aioreq_nice $pri_adjust
+Similar to C<aioreq_pri>, but subtracts the given value from the current
+priority, so effects are cumulative.
 =item aio_open $pathname, $flags, $mode, $callback->($fh)
 Asynchronously open or create a file and call the callback with a newly
 created filehandle for the file.
       $_[0] > 0 or die "read error: $!";
       print "read $_[0] bytes: <$buffer>\n";
    };
 =item aio_move $srcpath, $dstpath, $callback->($status)
-[EXPERIMENTAL due to internal aio_group use]
 Try to move the I<file> (directories not supported as either source or
 destination) from C<$srcpath> to C<$dstpath> and call the callback with
 the C<0> (error) or C<-1> ok.
 The callback a single argument which is either C<undef> or an array-ref
 with the filenames.
 =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
-[EXPERIMENTAL due to internal aio_group use]
 Scans a directory (similar to C<aio_readdir>) but additionally tries to
 separate the entries of directory C<$path> into two sets of names, ones
 you can recurse into (directories or links to them), and ones you cannot
 recurse into (everything else).
 [EXPERIMENTAL]
 This is a very special aio request: Instead of doing something, it is a
 container for other aio requests, which is useful if you want to bundle
-many requests into a single, composite, request.
+many requests into a single, composite, request with a definite callback
+and the ability to cancel the whole request with its subrequests.
 Returns an object of class L<IO::AIO::GRP>. See its documentation below
 for more info.
 Example:
 phase and still requires a worker thread. Thus, the callback will not
 be executed immediately but only after other requests in the queue have
 entered their execution phase. This can be used to measure request
 latency.
-=item IO::AIO::aio_sleep $fractional_seconds, $callback->()  *NOT EXPORTED*
+=item IO::AIO::aio_busy $fractional_seconds, $callback->()  *NOT EXPORTED*
 Mainly used for debugging and benchmarking, this aio request puts one of
 the request workers to sleep for the given time.
 While it is theoretically handy to have simple I/O scheduling requests
-like sleep and file handle readable/writable, the overhead this creates
+like sleep and file handle readable/writable, the overhead this creates is
-is immense, so do not use this function except to put your application
+immense (it blocks a thread for a long time) so do not use this function
-under artificial I/O pressure.
+except to put your application under artificial I/O pressure.
 =back
 =head2 IO::AIO::REQ CLASS
 example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
 requests, delaying any later requests for a long time.
 To avoid this, and allow incremental generation of requests, you can
 instead a group and set a feeder on it that generates those requests. The
-feed callback will be called whenever there are few enough (see C<feed_limit>,
+feed callback will be called whenever there are few enough (see C<limit>,
 below) requests active in the group itself and is expected to queue more
 requests.
-The feed can queue as many requests as it likes (i.e. C<add> does not
+The feed callback can queue as many requests as it likes (i.e. C<add> does
-impose any limits).
+not impose any limits).
 If the feed does not queue more requests when called, it will be
 automatically removed from the group.
 If the feed limit is C<0>, it will be set to C<2> automatically.
 Example:
    # stat all files in @files, but only ever use four aio requests concurrently:
    my $grp = aio_group sub { print "finished\n" };
-   feed_limit $grp 4;
+   limit $grp 4;
    feed $grp sub {
       my $file = pop @files
          or return;
       add $grp aio_stat $file, sub { ... };
    };
-=item feed_limit $grp $num
+=item limit $grp $num
 Sets the feeder limit for the group: The feeder will be called whenever
 the group contains less than this many requests.
 Setting the limit to C<0> will pause the feeding process.
 Each thread needs a stack area which is usually around 16k, sometimes much
 larger, depending on the OS.
 =head1 SEE ALSO
-L<Coro>, L<Linux::AIO> (obsolete).
+L<Coro::AIO>.
 =head1 AUTHOR
  Marc Lehmann <schmorp@schmorp.de>
  http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.67 by root, Tue Oct 24 02:25:16 2006 UTC vs. Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.67 by root, Tue Oct 24 02:25:16 2006 UTC vs.
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC