7d0b1d5695
The ray tracer is compute-bound and the three existing benches only cover alloc / megamorphic-dispatch / collections. Add three axes the epic needs to judge itself holistically: - mono-dispatch: monomorphic protocol dispatch. Its jolt/JVM ratio (~110x) is *worse* than megamorphic (~76x) — the JVM inline-caches a runtime-monomorphic call site to near-free while jolt does a full registry dispatch (devirt only fires on statically-proven receivers). Points at the call-site inline cache. - mandelbrot: pure float compute, no alloc/dispatch. The floor at ~15x — native arith already gets close to the JVM. - fib: recursion, call + integer-arith overhead. run.sh gains JVM=1, which runs each bench on JVM Clojure too and prints the jolt/JVM ratio. collections sized up now that the map is a HAMT (jolt-684u). README documents the axes and the current scorecard. Co-authored-by: Yogthos <yogthos@gmail.com>
48 lines
1.9 KiB
Clojure
48 lines
1.9 KiB
Clojure
;; mandelbrot — pure floating-point compute: for each point of an NxN grid,
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;; iterate z = z^2 + c up to a cap and count iterations. No allocation, no
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;; dispatch, no collections in the hot loop — just double arithmetic and tight
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;; recur loops. This isolates the irreducible-math axis the ray tracer is bound
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;; on (where devirt/alloc passes measured flat), so it tracks native-arith codegen
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;; (jolt-3pl) and loop quality directly.
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;;
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;; Portable Clojure (jolt + JVM Clojure).
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;; jolt -m mandelbrot 1000 (JOLT_DIRECT_LINK=1 JOLT_WHOLE_PROGRAM=1)
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(ns mandelbrot)
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(defn count-point [cr ci cap]
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(loop [i 0 zr 0.0 zi 0.0]
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(if (or (>= i cap) (> (+ (* zr zr) (* zi zi)) 4.0))
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i
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(recur (inc i)
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(+ (- (* zr zr) (* zi zi)) cr)
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(+ (* 2.0 (* zr zi)) ci)))))
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(defn run [n]
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(let [cap 200
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nd (* 1.0 n)]
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(loop [y 0 acc 0]
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(if (< y n)
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(let [ci (- (/ (* 2.0 y) nd) 1.0)
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row (loop [x 0 a 0]
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(if (< x n)
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(let [cr (- (/ (* 2.0 x) nd) 1.5)]
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(recur (inc x) (+ a (count-point cr ci cap))))
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a))]
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(recur (inc y) (+ acc row)))
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acc))))
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(defn -main [& args]
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(let [n (if (seq args) (Integer/parseInt (first args)) 1000)]
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(dotimes [_ 2] (run (quot n 2))) ; warmup
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(let [runs 3
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times (mapv (fn [_]
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(let [t0 (System/nanoTime)
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r (run n)
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ms (/ (- (System/nanoTime) t0) 1000000.0)]
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[ms r]))
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(range runs))
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mss (mapv first times)
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mean (/ (reduce + mss) runs)]
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(println "mandelbrot n" n "result" (second (first times)))
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(println "runs:" (mapv (fn [t] (/ (Math/round (* t 10.0)) 10.0)) mss))
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(println "mean:" (/ (Math/round (* mean 10.0)) 10.0) "ms"))))
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