That Go pi-digits program is 50% faster than a Java program that also uses the GMP library, just like the Go program!
That Go pi-digits program is only 4% faster than a PHP program that uses the GMP library.
It's not enough to "point out that most languages have C FFIs" when for this arbitrary precision arithmetic task GMP is allowed and others step-up and contribute those programs.
I see. I had only looked at the source code of the Nodejs competitor. To be fair the point still stands that you need to read the source to know what is really being measured.
It’s fifty percent faster than the competing java program.