I understand that pmap needs to have big chunks to overcome the overhead but I don't understand my results
(defn t [m] (dotimes [i m] (rand)) (Thread/sleep 1000)) (defn testmap [f n m] (time (doall (f t (repeat n m))))) user=> (testmap map 8 100) "Elapsed time: 8108.174484 msecs" (nil nil nil nil nil nil nil nil) user=> (testmap pmap 8 100) "Elapsed time: 1006.797146 msecs" (nil nil nil nil nil nil nil nil) user=> (testmap pmap 8 1000000) "Elapsed time: 3781.967909 msecs" (nil nil nil nil nil nil nil nil) user=> (testmap map 8 1000000) "Elapsed time: 8544.896008 msecs" (nil nil nil nil nil nil nil nil) user=> (testmap map 8 10000000) "Elapsed time: 10663.057874 msecs" (nil nil nil nil nil nil nil nil) user=> (testmap pmap 8 10000000) "Elapsed time: 29525.579612 msecs" (nil nil nil nil nil nil nil nil) I'm using an i7 with 8 processors so the Thread alone mostly gives an 8-fold speedup. Calling (rand) more times impacts pmap even though I map and pmap on a list of size 8 to spawn eight functions each with a lot of work. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
