1e7 : 8400511 685

  1 core
    collatz_longest          1m16.034s  MCE Perl code
    collatz_longest_pdl      0m13.691s  Consumes 39 MiB
    collatz_longest_filemap  0m06.615s  Consumes 59 MiB
    collatz_longest_scalar   0m06.148s  Consumes 39 MiB
    collatz_longest_array    0m04.986s  Consumes 330 MiB
    collatz_longest_c1       0m01.868s  Inline C code
    collatz_longest_c2       0m00.778s  Inline C code