jolt/bench/dispatch.clj
Yogthos 5a5ea8058a Make the benchmark harness build optimized binaries on Chez
bench/run.sh was Janet-era: it invoked a 'jolt' binary and set
JOLT_DIRECT_LINK/JOLT_WHOLE_PROGRAM, none of which exist on Chez, where
'joltc run -m' runs fully unoptimized (direct-link and inline default off). So
the suite was measuring jolt's unoptimized path.

run.sh now compiles each benchmark to an optimized AOT binary (joltc build
--direct-link --opt) and times it against JVM Clojure on the same portable
source, auto-detecting the Chez kernel dev files like build-smoke.sh. Adds
bench/deps.edn so joltc resolves the namespaces, NO_JVM to skip the reference.

mandelbrot.clj dropped its jolt.png require so the JVM reference can run it; the
picture demo moved to mandelbrot_png.clj (jolt-only). README scorecard refreshed
with current Chez numbers and the two-regime read (compute ~8-10x substrate floor;
dispatch/alloc ~120-330x architectural gaps the passes don't touch). Stale
'jolt -m' header lines point at bench/run.sh.
2026-06-25 23:47:39 -04:00

56 lines
2.3 KiB
Clojure

;; dispatch — a POLYMORPHIC-DISPATCH stress test. A protocol method is called in
;; a hot loop over a heterogeneous (megamorphic) collection of record types, with
;; minimal per-call work, so protocol dispatch dominates. This is the regime
;; devirtualization and the inline-cache target, and the one the ray
;; tracer can't reveal — its dispatch is monomorphic and a small fraction of the
;; float-math cost (devirt measured FLAT there).
;;
;; Portable Clojure (jolt + JVM Clojure).
;; bench/run.sh dispatch 20000
(ns dispatch)
(defprotocol Shape
(area [s])
(sides [s]))
(defrecord Circle [r] Shape (area [_] (* (* 3.14159 r) r)) (sides [_] 0))
(defrecord Square [s] Shape (area [_] (* s s)) (sides [_] 4))
(defrecord Triangle [b h] Shape (area [_] (* (* 0.5 b) h)) (sides [_] 3))
(defrecord Rect [w h] Shape (area [_] (* w h)) (sides [_] 4))
(defn build-shapes [n]
(mapv (fn [i]
(let [k (mod i 4)]
(cond
(= k 0) (->Circle (+ 1 (mod i 7)))
(= k 1) (->Square (+ 1 (mod i 5)))
(= k 2) (->Triangle (+ 1 (mod i 3)) (+ 2 (mod i 6)))
:else (->Rect (+ 1 (mod i 4)) (+ 1 (mod i 8))))))
(range n)))
;; megamorphic: every element may be a different type -> the call site sees all 4
(defn sum-area [shapes]
(reduce (fn [acc s] (+ (+ acc (area s)) (sides s))) 0.0 shapes))
(defn run [iters]
(let [shapes (build-shapes 1000)]
(loop [i 0 acc 0.0]
(if (< i iters)
(recur (inc i) (+ acc (sum-area shapes)))
acc))))
(defn -main [& args]
(let [iters (if (seq args) (Integer/parseInt (first args)) 20000)]
(dotimes [_ 2] (run (quot iters 4))) ; warmup
(let [runs 3
times (mapv (fn [_]
(let [t0 (System/nanoTime)
r (run iters)
ms (/ (- (System/nanoTime) t0) 1000000.0)]
[ms r]))
(range runs))
mss (mapv first times)
mean (/ (reduce + mss) runs)]
(println "dispatch iters" iters "result" (second (first times)))
(println "runs:" (mapv (fn [t] (/ (Math/round (* t 10.0)) 10.0)) mss))
(println "mean:" (/ (Math/round (* mean 10.0)) 10.0) "ms"))))