Reducers Comparison

reducers.cljc

(require '[clojure.core.reducers :as r])

(defn wait [millis]
  #?(:clj (Thread/sleep millis)
     :clje (timer/sleep millis)))

(defmacro times
  {:added "1.0"}
  [& exprs]
  `(do
     ~@(for [expr exprs]
         `(let [start# #?(:clj (. System (nanoTime))
                          :clje (erlang/monotonic_time :nano_seconds))
                ret#   ~expr
                stop#  #?(:clj (. System (nanoTime))
                          :clje (erlang/monotonic_time :nano_seconds))]
            (println ret#
                     (str "(" (/ (- stop# start#) 1000000.0)
                          " msecs)"))))))

(defn t1 []
  (let [x (vec (range 1000000))]
        (times (r/fold + + x)
               (r/reduce + x)
               (reduce + x))))

(t1)

reducers.txt

;; Clojure 1.8 - JVM 1.8
user=> (load-file "reducers.cljc")
499999500000 (5.646464 msecs)
499999500000 (10.339637 msecs)
499999500000 (11.566281 msecs)
nil

;; Clojure 0.6.0-1962.08bd5b3 - Erlang OTP 22.2
clje.user=> (load-file "reducers.cljc")
499999500000 (3484.922 msecs)
499999500000 (198.954 msecs)
499999500000 (152.782 msecs)
nil