Changeset 2447a1ba09d4f7cff926232db18cfe3ac3c96ea6

Timestamp:

10/27/09 20:52:15 (4 weeks ago)

Author:

Nelson Elhage <nelhage@mit.edu>

git-author:

Nelson Elhage <nelhage@mit.edu> / 2009-10-26T21:39:46Z-0400

Parents:

369707ed232a584a6b9f06c3e2c84ce4eb9f281e

Children:

0b21230c60038729b397adb87a85bb71f24a661c

git-committer:

Nelson Elhage <nelhage@mit.edu> / 2009-10-27T20:52:15Z-0400

Message:

Performance improvement in fixup.

Turn the single loop into two nested loops with part of fill_forward
inlined, and use aliases to speed up access to the loop variable.

This is about a 10% speedup for large message-list walking operations.

Files:

• perl/lib/BarnOwl/View/Iterator.pm (modified) (2 diffs)

perl/lib/BarnOwl/View/Iterator.pm

@@ -8 +8 @@
 sub view {return shift->{view}}
 sub index {return shift->{index}}
+
+our ($i, $v);
 
 sub new {
@@ -127 +129 @@
     my $self = shift;
 
-    # This check is redudant, in that this is exactly the test that
-    # the below code would end up doing anyways. However, profiling
-    # reveals that fast-tracking the common case like this is a huge
-    # performance win, since this is probably /the/ the hottest piece
-    # of code path when walking views.
-    return 0 if $self->{index} < $self->range->next_fwd
-      && $self->{view}->message($self->{index});
+    local *i = \$self->{index};
+    local *v = \$self->{view};
 
-    return 1 if $self->fill_forward;
-
-    while(!$self->{view}->message($self->{index})) {
-        $self->{index}++;
+    do {
+        while($i < $self->range->next_fwd) {
+            return 0 if $v->message($i);
+            $i++;
+        }
         return 1 if $self->fill_forward;
-    }
+    } while(!$v->message($i));
     return 0;
 }