diff --git a/devices/test/devices/monitoring_performance_test.py b/devices/test/devices/monitoring_performance_test.py
index b919f84eae4d5616e4fb57cd023945507aa1df71..777dbdf941b1c48eb693cbe18b9cb1fed2f09aee 100644
--- a/devices/test/devices/monitoring_performance_test.py
+++ b/devices/test/devices/monitoring_performance_test.py
@@ -23,13 +23,23 @@ from time import time
 
 __all__ = ["Monitoring_Performance_Device", "main"]
 
+SMALL = 10000
+BIG = 1000000
+
 logger = logging.getLogger()
 logger.setLevel(logging.INFO)
 
 def read(size):
-    logger.info("read")
     return numpy.array([random.random(), ] * size)
 
+def read_small():
+    logger.info("read_small")
+    return read(SMALL)
+
+def read_big():
+    logger.info("read_big")
+    return read(BIG)
+
 class Monitoring_Performance_Device(Device):
     small_array_r = attribute(
         dtype = (numpy.double,),
@@ -41,7 +51,7 @@ class Monitoring_Performance_Device(Device):
         archive_rel_change = 0.1,
         max_value = 1.0,
         min_value = 0.0,
-        fget = read(10000),
+        fget = read_small,
     )
 
     big_array_r = attribute(
@@ -53,7 +63,7 @@ class Monitoring_Performance_Device(Device):
         archive_rel_change = 0.1,
         max_value = 1.0,
         min_value = 0.0,
-        fget = read(1000000),
+        fget = read_big,
     )
 
     def init_device(self):