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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.73 by root, Tue Oct 24 16:35:04 2006 UTC vs.
Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC

                      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 aioreq_nice));
    our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
-                       min_parallel max_parallel max_outstanding nreqs);
+                       min_parallel max_parallel nreqs nready npending);
    @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
    require XSLoader;
    XSLoader::load ("IO::AIO", $VERSION);
 environment, d) use Glib::filename_from_unicode on unicode filenames or e)
 use something else.
 =over 4
-=item aioreq_pri $pri
+=item $prev_pri = aioreq_pri [$pri]
-Sets the priority for the next aio request. The default priority
+Returns the priority value that would be used for the next request and, if
+C<$pri> is given, sets the priority for the next aio request.
-is C<0>, the minimum and maximum priorities are C<-4> and C<4>,
+The default priority is C<0>, the minimum and maximum priorities are C<-4>
-respectively. Requests with higher priority will be serviced first.
+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_>
+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):
 =cut
 sub aio_move($$$) {
    my ($src, $dst, $cb) = @_;
+   my $pri = aioreq_pri;
    my $grp = aio_group $cb;
+   aioreq_pri $pri;
    add $grp aio_rename $src, $dst, sub {
       if ($_[0] && $! == EXDEV) {
+         aioreq_pri $pri;
          add $grp aio_open $src, O_RDONLY, 0, sub {
             if (my $src_fh = $_[0]) {
                my @stat = stat $src_fh;
+               aioreq_pri $pri;
                add $grp aio_open $dst, O_WRONLY, 0200, sub {
                   if (my $dst_fh = $_[0]) {
+                     aioreq_pri $pri;
                      add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
                         close $src_fh;
                         if ($_[0] == $stat[7]) {
                            utime $stat[8], $stat[9], $dst;
                            chmod $stat[2] & 07777, $dst_fh;
                            chown $stat[4], $stat[5], $dst_fh;
                            close $dst_fh;
+                           aioreq_pri $pri;
                            add $grp aio_unlink $src, sub {
                               $grp->result ($_[0]);
                            };
                         } else {
                            my $errno = $!;
+                           aioreq_pri $pri;
                            add $grp aio_unlink $dst, sub {
                               $! = $errno;
                               $grp->result (-1);
                            };
                         }
 with the filenames.
 =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
 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
+efficiently separate the entries of directory C<$path> into two sets of
-you can recurse into (directories or links to them), and ones you cannot
+names, directories you can recurse into (directories), and ones you cannot
-recurse into (everything else).
+recurse into (everything else, including symlinks to directories).
 C<aio_scandir> is a composite request that creates of many sub requests_
 C<$maxreq> specifies the maximum number of outstanding aio requests that
 this function generates. If it is C<< <= 0 >>, then a suitable default
-will be chosen (currently 6).
+will be chosen (currently 4).
 On error, the callback is called without arguments, otherwise it receives
 two array-refs with path-relative entry names.
 Example:
 =cut
 sub aio_scandir($$$) {
    my ($path, $maxreq, $cb) = @_;
+   my $pri = aioreq_pri;
    my $grp = aio_group $cb;
-   $maxreq = 6 if $maxreq <= 0;
+   $maxreq = 4 if $maxreq <= 0;
    # stat once
+   aioreq_pri $pri;
    add $grp aio_stat $path, sub {
       return $grp->result () if $_[0];
       my $now = time;
       my $hash1 = join ":", (stat _)[0,1,3,7,9];
       # read the directory entries
+      aioreq_pri $pri;
       add $grp aio_readdir $path, sub {
          my $entries = shift
             or return $grp->result ();
          # stat the dir another time
+         aioreq_pri $pri;
          add $grp aio_stat $path, sub {
             my $hash2 = join ":", (stat _)[0,1,3,7,9];
             my $ndirs;
                               map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
                                  @$entries];
             my (@dirs, @nondirs);
-            my ($statcb, $schedcb);
-            my $nreq = 0;
-            my $statgrp = add $grp aio_group;
+            my $statgrp = add $grp aio_group sub {
+               $grp->result (\@dirs, \@nondirs);
+            };
-            $schedcb = sub {
+            limit $statgrp $maxreq;
-               if (@$entries) {
+            feed $statgrp sub {
-                  if ($nreq < $maxreq) {
+               return unless @$entries;
-                     my $ent = pop @$entries;
+               my $entry = pop @$entries;
+               aioreq_pri $pri;
+               add $statgrp aio_stat "$path/$entry/.", sub {
+                  if ($_[0] < 0) {
+                     push @nondirs, $entry;
+                  } else {
+                     # need to check for real directory
+                     aioreq_pri $pri;
+                     add $statgrp aio_lstat "$path/$entry", sub {
+                        if (-d _) {
+                           push @dirs, $entry;
+                           unless (--$ndirs) {
+                              push @nondirs, @$entries;
+                              feed $statgrp;
+                           }
+                        } else {
+                           push @nondirs, $entry;
+                        }
-                     $nreq++;
+                     }
-                     add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
                   }
-               } elsif (!$nreq) {
-                  # finished
-                  $statgrp->cancel;
-                  undef $statcb;
-                  undef $schedcb;
-                  $grp->result (\@dirs, \@nondirs);
-               }
+               };
             };
-            $statcb = sub {
-               my ($status, $entry) = @_;
-               if ($status < 0) {
-                  $nreq--;
-                  push @nondirs, $entry;
-                  &$schedcb;
-               } else {
-                  # need to check for real directory
-                  add $grp aio_lstat "$path/$entry", sub {
-                     $nreq--;
-                     if (-d _) {
-                        push @dirs, $entry;
-                        if (!--$ndirs) {
-                           push @nondirs, @$entries;
-                           $entries = [];
-                        }
-                     } else {
-                        push @nondirs, $entry;
-                     }
-                     &$schedcb;
-                  }
-               }
-            };
-            &$schedcb while @$entries && $nreq < $maxreq;
          };
       };
    };
    $grp
 If this call isn't available because your OS lacks it or it couldn't be
 detected, it will be emulated by calling C<fsync> instead.
 =item aio_group $callback->(...)
-[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 with a definite callback
 and the ability to cancel the whole request with its subrequests.
 =item * They can also can also be added to other IO::AIO::GRP objects.
 =item * You must not add requests to a group from within the group callback (or
 any later time).
-=item * This does not harmonise well with C<max_outstanding>, so best do
-not combine C<aio_group> with it. Groups and feeders are recommended for
-this kind of concurrency-limiting.
 =back
 Their lifetime, simplified, looks like this: when they are empty, they
 will finish very quickly. If they contain only requests that are in the
 C<done> state, they will also finish. Otherwise they will continue to
 be added, including other groups, as long as you do not create circular
 dependencies.
 Returns all its arguments.
+=item $grp->cancel_subs
+Cancel all subrequests and clears any feeder, but not the group request
+itself. Useful when you queued a lot of events but got a result early.
 =item $grp->result (...)
 Set the result value(s) that will be passed to the group callback when all
-subrequests have finished. By default, no argument will be passed.
+subrequests have finished and set thre groups errno to the current value
+of errno (just like calling C<errno> without an error number). By default,
+no argument will be passed and errno is zero.
+=item $grp->errno ([$errno])
+Sets the group errno value to C<$errno>, or the current value of errno
+when the argument is missing.
+Every aio request has an associated errno value that is restored when
+the callback is invoked. This method lets you change this value from its
+default (0).
+Calling C<result> will also set errno, so make sure you either set C<$!>
+before the call to C<result>, or call c<errno> after it.
 =item feed $grp $callback->($grp)
-[VERY EXPERIMENTAL]
 Sets a feeder/generator on this group: every group can have an attached
 generator that generates requests if idle. The idea behind this is that,
 although you could just queue as many requests as you want in a group,
 this might starve other requests for a potentially long time.  For
 Process all outstanding events on the result pipe. You have to call this
 regularly. Returns the number of events processed. Returns immediately
 when no events are outstanding.
+If not all requests were processed for whatever reason, the filehandle
+will still be ready when C<poll_cb> returns.
 Example: Install an Event watcher that automatically calls
 IO::AIO::poll_cb with high priority:
    Event->io (fd => IO::AIO::poll_fileno,
               poll => 'r', async => 1,
               cb => \&IO::AIO::poll_cb);
+=item IO::AIO::poll_some $max_requests
+Similar to C<poll_cb>, but only processes up to C<$max_requests> requests
+at a time.
+Useful if you want to ensure some level of interactiveness when perl is
+not fast enough to process all requests in time.
+Example: Install an Event watcher that automatically calls
+IO::AIO::poll_some with low priority, to ensure that other parts of the
+program get the CPU sometimes even under high AIO load.
+   Event->io (fd => IO::AIO::poll_fileno,
+              poll => 'r', nice => 1,
+              cb => sub { IO::AIO::poll_some 256 });
 =item IO::AIO::poll_wait
 Wait till the result filehandle becomes ready for reading (simply does a
 C<select> on the filehandle. This is useful if you want to synchronously wait
 for some requests to finish).
 See C<nreqs> for an example.
 =item IO::AIO::nreqs
-Returns the number of requests currently outstanding (i.e. for which their
+Returns the number of requests currently in the ready, execute or pending
-callback has not been invoked yet).
+states (i.e. for which their callback has not been invoked yet).
 Example: wait till there are no outstanding requests anymore:
    IO::AIO::poll_wait, IO::AIO::poll_cb
       while IO::AIO::nreqs;
+=item IO::AIO::nready
+Returns the number of requests currently in the ready state (not yet
+executed).
+=item IO::AIO::npending
+Returns the number of requests currently in the pending state (executed,
+but not yet processed by poll_cb).
 =item IO::AIO::flush
 Wait till all outstanding AIO requests have been handled.
 This module automatically runs C<max_parallel 0> at program end, to ensure
 that all threads are killed and that there are no outstanding requests.
 Under normal circumstances you don't need to call this function.
-=item $oldnreqs = IO::AIO::max_outstanding $nreqs
+=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
-[DEPRECATED]
+This is a very bad function to use in interactive programs because it
+blocks, and a bad way to reduce concurrency because it is inexact: Better
+use an C<aio_group> together with a feed callback.
 Sets the maximum number of outstanding requests to C<$nreqs>. If you
-try to queue up more than this number of requests, the caller will block until
+to queue up more than this number of requests, the next call to the
-some requests have been handled.
+C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
+function will block until the limit is no longer exceeded.
-The default is very large, so normally there is no practical limit. If you
+The default value is very large, so there is no practical limit on the
-queue up many requests in a loop it often improves speed if you set
+number of outstanding requests.
-this to a relatively low number, such as C<100>.
-This function does not work well together with C<aio_group>'s, and their
+You can still queue as many requests as you want. Therefore,
-feeder interface is better suited to limiting concurrency, so do not use
+C<max_oustsanding> is mainly useful in simple scripts (with low values) or
-this function.
+as a stop gap to shield against fatal memory overflow (with large values).
-Under normal circumstances you don't need to call this function.
 =back
 =cut
    *$sym
 }
 min_parallel 8;
-END {
-   max_parallel 0;
-}
 1;
 =head2 FORK BEHAVIOUR

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.73 by root, Tue Oct 24 16:35:04 2006 UTC vs. Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.73 by root, Tue Oct 24 16:35:04 2006 UTC vs.
Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC