Your benchmarking is not fair. The place is hihgly dependend on input data. E.g. if you use only     'abcdedcbabcdefgfedcbabcdefghijklmnonmlkjihgfedcbabcdefghijklkjihgfedcbabcdefghijklmnoponmlkjihgfedcba' you get other results.

I can't imagine a fair benchmark because it must go through all possible permutations for short and very very long strings. Or it must use random input data and calculate the statistics.