diff --git a/mercurial/progress.py b/mercurial/progress.py
--- a/mercurial/progress.py
+++ b/mercurial/progress.py
@@ -104,6 +104,7 @@
         self.order = self.ui.configlist('progress', 'format')
         self.estimateinterval = self.ui.configwith(
             float, 'progress', 'estimateinterval')
+        self.debug = self.ui.configbool('progress', 'debug')
 
     def show(self, now, topic, pos, item, unit, total):
         if not shouldprint(self.ui):
diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -1693,6 +1693,14 @@
         elif self._progbar is not None:
             self._progbar.progress(topic, pos, item=item, unit=unit,
                                    total=total)
+
+            # Looking up progress.debug in tight loops is expensive. The value
+            # is cached on the progbar object and we can avoid the lookup in
+            # the common case where a progbar is active.
+            if pos is None or not self._progbar.debug:
+                return
+
+        # Keep this logic in sync with above.
         if pos is None or not self.configbool('progress', 'debug'):
             return