As already mentioned use identical? In ClojureScript you must use keyword-identical? for fast comparisons.
On Friday, October 10, 2014, Jony Hudson <jonyepsi...@gmail.com> wrote: > Hi All, > > I've been optimising a piece of code lately, and have come to wonder > about the performance of keyword comparison. Specifically, I'm not sure > whether the performance I'm seeing is what is expected. The data structures > page on clojure.org [1] indicates that keywords "provide very fast > equality tests". If I micro-benchmark with criterium, then I find the > following: > > As a baseline, comparing integers with `(= 0 1)` takes around 4ns. > > Comparing keywords with `(= :plus :minus)` takes around 30ns. > > This is about the same amount of time it takes to compare strings, `(= > "plus" "minus")`, which comes in at about 25ns. > > This surprised me, as I would have guessed that "fast" would have been > closer to the integer performance than the string performance. It's worth > saying that I don't know a lot about benchmarking, but I do have some > "real" code that's performance depends heavily on comparisons, and it seems > to line up performance-wise with these micro-benchmarks. > > So, am I doing something silly (like I don't know about the fast = for > keywords)? Or, are my expectations wrong, and this is about how long "fast" > should be? Or is there a performance bug lurking? > > I'm using Clojure 1.6.0 (but have tried 1.5.0 and 1.7.0-alpha1 with > similar results). > x86_64 Mac OS X 10.9.5 4 cpu(s) > > Java HotSpot(TM) 64-Bit Server VM 25.5-b02 > > Thanks in advance for any input, > > > Jony > > [1] http://clojure.org/data%5Fstructures > > -- > 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 > <javascript:_e(%7B%7D,'cvml','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 > <javascript:_e(%7B%7D,'cvml','clojure%2bunsubscr...@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 > <javascript:_e(%7B%7D,'cvml','clojure%2bunsubscr...@googlegroups.com');>. > For more options, visit https://groups.google.com/d/optout. > -- 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/d/optout.
