I have added nbody6.f90 to GitHub - fortran-lang/benchmarks: Fortran benchmarks . This is a modified version of the older version at the Debian benchmarks site.
The performance results at the Debian site already show Fortran as among the fastest.
An older thread on this forum, Fortran Benchmark, involves the Nbody example.
On my PC, using Ifort OneAPI 2021.5 in Windows 11, my modifications gave a speed gain of 18 percent compared to the older Fortran program, and the new Fortran version is about 13 percent faster than the Julia version on the Debian benchmarks site.
In this version, the special technique of using the X64 SSE instruction RSQRTSS to generate a single precision approximation to 1/sqrt(x), followed by a single iteration of double precision Newton-Raphson polishing the root, which is used in the Julia version of Nbody, is not used since it did not yield better performance than the straightforward calculation of x^(-3/2), for a given x.
This is the first time that I uploaded a file to Github, and what I uploaded may not have ended up in the proper subdirectory. Sorry!