fixed positive bias in local rate estimation at start

diff --git a/p2pool/util/math.py b/p2pool/util/math.py
index eb109c1..0e2866e 100644 (file)
--- a/p2pool/util/math.py
+++ b/p2pool/util/math.py
@@ -243,9 +243,10 @@ class RateMonitor(object):
     def add_datum(self, datum):
         self._prune()
         t = time.time()
-        self.datums.append((t, datum))
         if self.first_timestamp is None:
             self.first_timestamp = t
+        else:
+            self.datums.append((t, datum))
 
 if __name__ == '__main__':
     import random