pmap_batched.clj

(defn pmap-batched [n f xs]                                    
  (let [k (int (/ (count xs) n))]
    (apply concat (pmap #(doall (map f %)) (partition-all k xs)))))

(defn compute [x] (Thread/sleep 1) x)

(defn compute-all
  [batches n]
  (pmap-batched batches compute (range n)))

(comment

  (time (count (compute-all 1 1000)))
  "Elapsed time: 1098.985 msecs"
  1000

  (time (count (compute-all 2 1000)))
  "Elapsed time: 548.367 msecs"
  1000

  )