Found this blog post written by fogus: "To provide this level of flexibility Clojure establishes a level of indirection. Specifically, all function lookups through a Var occur, at the lowest level, through an atomic volatile. This happens every time that a function bound using the def/defn special forms is called. This indirection is not amenable to HotSpot optimizations."
http://blog.fogus.me/2011/10/14/why-clojure-doesnt-need-invokedynamic-but-it-might-be-nice/ On Apr 25, 10:19 pm, Alice <dofflt...@gmail.com> wrote: > I create many small methods in java without worrying about the > performance since it's usually the target of inline optimization. For > example, > > public class Foo { > public static long inc(long l) { > return ++l; > } > > public static long f1() { > long l = 0; > for (int i=0; i < 1000000000; i++) { > l++; > } > return l; > } > > public static long f2() { > long l = 0; > for (int i=0; i < 1000000000; i++) { > l = inc(l); > } > return l; > } > > } > > (time (Foo/f1)) > (time (Foo/f1)) > (time (Foo/f1)) > (time (Foo/f2)) > (time (Foo/f2)) > (time (Foo/f2)) > > "Elapsed time: 23.309532 msecs" > "Elapsed time: 23.333039 msecs" > "Elapsed time: 21.714753 msecs" > "Elapsed time: 22.943366 msecs" > "Elapsed time: 21.612783 msecs" > "Elapsed time: 21.71376 msecs" > > But clojure funtions seem to be never get inlined. > > (def obj (Object.)) > > (defn getObj [] obj) > > (defn f1 [] obj) > (defn f2 [] (getObj)) > > (time (dotimes [n 100000000] (f1))) > (time (dotimes [n 100000000] (f1))) > (time (dotimes [n 100000000] (f1))) > (time (dotimes [n 100000000] (f2))) > (time (dotimes [n 100000000] (f2))) > (time (dotimes [n 100000000] (f2))) > > "Elapsed time: 67.758744 msecs" > "Elapsed time: 68.555306 msecs" > "Elapsed time: 68.725147 msecs" > "Elapsed time: 104.810459 msecs" > "Elapsed time: 103.273618 msecs" > "Elapsed time: 103.374595 msecs" -- -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
