Hi, On Sun 17 Apr 2016 12:44, l...@gnu.org (Ludovic Courtès) writes:
> Andy Wingo <wi...@pobox.com> skribis: > >> I want to test four things. >> >> ;; 1. How long a loop up to 10 million takes (baseline measurement). >> (let ((port (open-input-string "s"))) (do-times #e1e7 1)) >> >> ;; 2. A call to a simple Scheme function. >> (define (foo port) 42) >> (let ((port (open-input-string "s"))) (do-times #e1e7 (foo port))) >> >> ;; 3. A call to a port subr. >> (let ((port (open-input-string "s"))) (do-times #e1e7 (port-line port))) >> >> ;; 4. A call to a port subr that touches the buffer. >> (let ((port (open-input-string "s"))) (do-times #e1e7 (peek-char port))) >> >> The results: >> >> | baseline | foo | port-line | peek-char >> ------------------+----------+--------+-----------+---------- >> guile 2.0 | 0.269s | 0.845s | 1.067s | 1.280s >> guile master | 0.058s | 0.224s | 0.225s | 0.433s >> wip-port-refactor | 0.058s | 0.220s | 0.226s | 0.375s > > Oh, nice! (By “prohibitively slow” I was referring to 2.0.) > > For ‘peek-char’, isn’t there also the fact that string ports in 2.2 are > UTF-8 by default, so we get the fast path, whereas in 2.0 there > ‘%default-port-encoding’, which could be something else leading to the > slow path? I tried making sure the string port was a UTF-8 port but that made no difference to the 2.0 peek-char times. I suspect this is because I ran it at the REPL, which had done a setlocale() already. But perhaps that's not the right explanation. Andy
