diff --git a/livebridge/profiler.py b/livebridge/profiler.py
index 02ced62..e62c61e 100644
--- a/livebridge/profiler.py
+++ b/livebridge/profiler.py
@@ -68,7 +68,7 @@ async def display_top(snapshot, key_type='lineno', limit=15):
 async def display_diff(snapshot, key_type='lineno', limit=15):
     global snapshot_prev
     if snapshot_prev:
-        logging.debug("Top %s differences" % limit)
+        logging.debug("Top %s differences from start" % limit)
         top_diffs= snapshot.compare_to(snapshot_prev, 'lineno')
         for x, stat in enumerate([x for x in top_diffs[:limit]], 1):
             frame = stat.traceback[0]
@@ -80,5 +80,6 @@ async def display_diff(snapshot, key_type='lineno', limit=15):
             if line:
                 logging.debug('    %s' % line)
         logging.debug("\n\n")
-    snapshot_prev = snapshot
+    if not snapshot_prev:
+        snapshot_prev = snapshot