As with many late 80s memory management papers, cache effects obsolete the conclusions in this one. In fact, the compiler's ability to coalesce all the stack allocations in a single procedure call into a single pair of stack manipulation instructions makes the conclusions almost meaningless in practice: inlining optimizations and modern CPUs make that cost essentially zero nowadays. I'd almost argue that the methodology in this paper, combined with 2015 assumptions, offers an effective argument against GC. Appel's memory management papers really need to be taken with a grain of salt :)