diff --git a/debug-viewer/GstDebugViewer/GUI/models.py b/debug-viewer/GstDebugViewer/GUI/models.py
index e760b2b2cb..d6482c691c 100644
--- a/debug-viewer/GstDebugViewer/GUI/models.py
+++ b/debug-viewer/GstDebugViewer/GUI/models.py
@@ -129,6 +129,13 @@ class LogModelBase (gtk.GenericTreeModel):
 
         return value
 
+    def get_value_range (self, col_id, start, stop):
+
+        if col_id != self.COL_LEVEL:
+            raise NotImplementedError ("XXX FIXME")
+
+        return self.line_levels[start:stop]
+
     def on_iter_next (self, line_index):
 
         last_index = len (self.line_offsets) - 1
diff --git a/debug-viewer/GstDebugViewer/Plugins/Timeline.py b/debug-viewer/GstDebugViewer/Plugins/Timeline.py
index 5eec14e3eb..65a7aedcee 100644
--- a/debug-viewer/GstDebugViewer/Plugins/Timeline.py
+++ b/debug-viewer/GstDebugViewer/Plugins/Timeline.py
@@ -171,13 +171,26 @@ class LevelDistributionSentinel (object):
         if not partitions:
             return
 
+        level_index = 0
+        level_iter = None
+
         finished = False
         while tree_iter:
             y -= 1
             if y == 0:
                 y = YIELD_LIMIT
                 yield True
-            level = model_get (tree_iter, id_level)
+            if level_iter is None:
+                stop_index = level_index + 512
+                levels = self.model.get_value_range (id_level,
+                                                     level_index, stop_index)
+                level_index = stop_index
+                level_iter = iter (levels)
+            try:
+                level = level_iter.next ()
+            except StopIteration:
+                level_iter = None
+                continue
             while i > partitions[partitions_i]:
                 data.append (tuple (counts))
                 counts = [0] * MAX_LEVELS
@@ -189,7 +202,6 @@ class LevelDistributionSentinel (object):
                 break
             counts[level] += 1
             i += 1
-            tree_iter = model_next (tree_iter)
 
         # Now handle the last one:
         data.append (tuple (counts))