diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 78007094ef..812ecce905 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -1862,7 +1862,7 @@ class TestRegexp < Test::Unit::TestCase
 
   def test_timeout_shorter_than_global
     omit "timeout test is too unstable on s390x" if RUBY_PLATFORM =~ /s390x/
-    per_instance_redos_test(10, 0.2, 0.2)
+    per_instance_redos_test(10, 0.5, 0.5)
   end
 
   def test_timeout_longer_than_global