You Benchmark is significantly flawed for the question asked. The OR (original replier) wanted to compare  index(lc $value,"true") with  $value =~ /true/i; In addition, to fairly benchmark one should try multiple test case (set  $value to "true", a short string, and a longer string in your test, and in a fair test, set it to: 'true', 'ashortstringthentrue', 'averylongstringthentrue', and different size strings without 'true' in them.