A Teenage Boy Improved Ruby 1.9 Performance Up to 63%

Japanese online magazine, @IT Jibun Senryaku Lab. (information site for IT engineers to educate and/or develop oneself), published an interview with a Japanese teenage boy, Masahiro Kanai, who improved the performance of several methods in Ruby 1.9. He is the age of high school freshman (the third grade of junior high school in Japanese school system). The article (written in Japanese) is here .

According to the article, Masahiro Kanai joined “the Security and Programming Camp 2009” this summer and chose the subject of Ruby’s performance improvement. His mentor was Koichi Sasada (ko1). The performances of the methods he worked have been bumped up 63% in maximum, 8% in average. His patches were applied to Ruby trunk in Oct. 5 this year.

What Masahiro Kanai did was fundamental for performance tuning. He took unnecessary macro references out from a loop. Masahiro spotted macros below in array.c, string.c, and struct.c were referred every time Ruby checked whether data was hold in a structure or not. Even though data were constants, Ruby saw the macros to judge data’s presence in every loop.

-RARRAY_PTR, RARRAY_LEN
-RSTRING_PTR, RSTRING_LEN
-RSTRUCT_PTR, RSTRUCT_LEN

He optimized the loop by eliminating macro references when data were constants.

Japanese people were surprised about the news since he made that in his age.
The interviewer acclaimed that he made it in his age.