diff --git a/test/uri/test_mailto.rb b/test/uri/test_mailto.rb
index 66f3edd..59bb5de 100644
--- a/test/uri/test_mailto.rb
+++ b/test/uri/test_mailto.rb
@@ -213,16 +213,18 @@ def test_check_to
   def test_email_regexp
     re = URI::MailTo::EMAIL_REGEXP
 
-    rate = 1000
+    repeat = 10
     longlabel = '.' + 'invalid'.ljust(63, 'd')
     endlabel = ''
-    pre = ->(n) {'a@invalid' + longlabel*(n*rate) + endlabel}
-    assert_linear_performance(1..10, pre: pre) do |to|
-      re =~ to or flunk
+    seq = (1..3).map {|i| 10**i}
+    rehearsal = 10
+    pre = ->(n) {'a@invalid' + longlabel*(n) + endlabel}
+    assert_linear_performance(seq, rehearsal: rehearsal, pre: pre) do |to|
+      repeat.times {re =~ to or flunk}
     end
     endlabel = '.' + 'email'.rjust(64, 'd')
-    assert_linear_performance(1..10, pre: pre) do |to|
-      re =~ to and flunk
+    assert_linear_performance(seq, rehearsal: rehearsal, pre: pre) do |to|
+      repeat.times {re =~ to and flunk}
     end
   end