wow, the #Chez #Scheme implementation of the #Shen #Prolog logic programming system[1] performs 4x faster than the #SBCL #Lisp implementation[2].
It seems like Mark Tarver, the author of Shen who reported these results, authored both implementations.
[1] https://shen-language.github.io/
[2] https://groups.google.com/g/chez-scheme/c/vTyTn_yh9vg/m/D8t-jooBGAAJ