fix parser perf test (#827)

can/tests/test_parser.py

@@ -12,6 +12,7 @@ class TestParser(unittest.TestCase):
   def _benchmark(self, signals, checks, thresholds, n):
     parser = CANParser('toyota_new_mc_pt_generated', signals, checks, 0, False)
     packer = CANPacker('toyota_new_mc_pt_generated')
+
     can_msgs = []
     for i in range(50000):
       values = {"ACC_CONTROL": {"ACC_TYPE": 1, "ALLOW_LONG_PRESS": 3}}
@@ -19,21 +20,25 @@ class TestParser(unittest.TestCase):
       bts = can_list_to_can_capnp(msgs, logMonoTime=int(0.01 * i * 1e9))
       can_msgs.append(bts)
 
-    if n > 1:
-      strings = []
-      for i in range(0, len(can_msgs), n):
-        strings.append(can_msgs[i:i + n])
-      t1 = time.process_time_ns()
-      for m in strings:
-        parser.update_strings(m)
-      t2 = time.process_time_ns()
-    else:
-      t1 = time.process_time_ns()
-      for m in can_msgs:
-        parser.update_string(m)
-      t2 = time.process_time_ns()
+    ets = []
+    for _ in range(25):
+      if n > 1:
+        strings = []
+        for i in range(0, len(can_msgs), n):
+          strings.append(can_msgs[i:i + n])
+        t1 = time.process_time_ns()
+        for m in strings:
+          parser.update_strings(m)
+        t2 = time.process_time_ns()
+      else:
+        t1 = time.process_time_ns()
+        for m in can_msgs:
+          parser.update_string(m)
+        t2 = time.process_time_ns()
 
-    et = t2 - t1
+      ets.append(t2 - t1)
+
+    et = sum(ets) / len(ets)
     avg_nanos = et / len(can_msgs)
     method = 'update_strings'  if n > 1 else 'update_string'
     print('%s: [%s] %.1fms to parse %s, avg: %dns' % (self._testMethodName, method, et/1e6, len(can_msgs), avg_nanos))