diff --git a/test_regress/t/t_wait_iface_vif.py b/test_regress/t/t_wait_iface_vif.py
index 3f6cb54fd..46d1fe4c0 100755
--- a/test_regress/t/t_wait_iface_vif.py
+++ b/test_regress/t/t_wait_iface_vif.py
@@ -11,7 +11,7 @@ import vltest_bootstrap
 
 test.scenarios('simulator')
 
-test.compile(verilator_flags2=['--binary', '--timescale 1ns/1ps'])
+test.compile(verilator_flags2=['--binary'])
 
 test.execute()
 
diff --git a/test_regress/t/t_wait_iface_vif.v b/test_regress/t/t_wait_iface_vif.v
index a91fc8445..7d697e8fe 100644
--- a/test_regress/t/t_wait_iface_vif.v
+++ b/test_regress/t/t_wait_iface_vif.v
@@ -45,7 +45,7 @@ class Driver;
   virtual my_if vif;
 
   task run();
-    vif.set_period(5ns);
+    vif.set_period(5);
     #10;
     vif.start_clk();
   endtask