I benchmarked the code with your modifications and the time taken drops from 50 seconds to 30 seconds which is pretty good. I need to look into the stuff provided by the SRFIs to see if they can help me write more idiomatic scheme.

Thanks very much,

Ian

I tried mimicking the C source, and ended up with the code below.
To get consistent timings, a nice trick triger the garbage collector
right before the expression to be timed.

(module test-heap mzscheme

(require
(prefix heap: (planet “heap.scm” (“soegaard” “galore.plt” 2 2)))
(lib “67.ss” “srfi”)
(lib “42.ss” “srfi”))

(define (print-ln . args)
(for-each display args)
(newline)
(flush-output))

(define (random-string len)
(string-ec (:range i len)
(integer->char (+ (random 26) 97))))

(define (populate-heap n)
(heap:heap-ec string-compare
(:range i n)
(random-string 5)))

(define (test:performance)
(collect-garbage)
(time
(random-seed 17)
(print-ln “Starting…”)
(print-ln (heap:find-min (populate-heap 1000000)))
(print-ln “Finished!”)))

(provide (all-defined)))

(require test-heap)
(test:performance)