diff --git a/lisa/trace.py b/lisa/trace.py
index a2f8d24860f668571fa1238409481385fa23a023..b772a5079d4c03370220ce4a7e4d6c72af9ff220 100644
--- a/lisa/trace.py
+++ b/lisa/trace.py
@@ -91,10 +91,8 @@ class TraceBase(abc.ABC):
         if not inplace:
             df = df.copy()
 
-        df.loc[df.index[:-1], col_name] = df.index.values[1:] - df.index.values[:-1]
-        # Fix the last event, which will have a NaN duration
-        # Set duration to trace_end - last_event
-        df.loc[df.index[-1], col_name] = self.end - df.index[-1]
+        df[col_name] = df.index
+        df[col_name] = df[col_name].diff().fillna(0)
 
         return df