diff --git a/tutorial/mpi4py/mpi4py_portable.py b/tutorial/mpi4py/mpi4py_portable.py
index 20b97bed..9f0bb4de 100644
--- a/tutorial/mpi4py/mpi4py_portable.py
+++ b/tutorial/mpi4py/mpi4py_portable.py
@@ -29,6 +29,9 @@ class EESSI_MPI4PY(rfm.RunOnlyRegressionTest):
     valid_systems = ['*']
 
     # ReFrame will generate a test for each module
+    # NOTE: each parameter adds a new dimension to the parametrization space.
+    # (EG 4 parameters with (3,3,2,2) possible values will result in 36 tests).
+    # Be mindful of how many parameters you add to avoid the number of tests generated being excessive.
     # https://reframe-hpc.readthedocs.io/en/stable/regression_test_api.html#reframe.core.builtins.parameter
     module_name = parameter(find_modules('mpi4py'))