For those of you playing along at home, I also ran Paul's chess program in YourKit with the sampling profiler. Here are all the calls that appear in the "HotSpots" view, along with time spent in those methods.
java.io.PushbackInputStream.read() 422977 clojure.lang.PersistentHashMap$HashCollisionNode.findIndex(Object) 206687 clojure.lang.Util.equiv(Object, Object) 204984 clojure.lang.PersistentHashMap$BitmapIndexedNode.find(int, int, Object, Object) 145968 clojure.lang.PersistentHashMap$NodeSeq.create(Object[]) 81031 clojure.lang.APersistentVector.doEquiv(IPersistentVector, Object) 41656 clojure.lang.Util.dohasheq(IHashEq) 31453 clojure.lang.RT.next(Object) 28671 clojure.lang.PersistentHashMap$NodeSeq.next() 24484 clojure.lang.PersistentVector$1.<init>(PersistentVector, int, int) 24015 I concur with Paul that it looks like the program is spending nearly all its time mired in hashing. Even the calls on here that aren't obviously related to hashing turn out on further inspection to be related to hashing. For example, doing a backtrace on Util.equiv, one sees that the = operation in the allowed? function is taking negligible time and the equiv method time is almost entirely spent in hash set lookup resolution. Similarly, the RT.next method is negligible time spent stepping through his for sequence, and appears to be almost entirely about stepping through hash collision nodes. My best guess at this point is that there is some sort of bug with the set implementation causing too many items to hash to the same bucket. I have seen this behavior before from time to time when profiling some of my own code (a suspiciously inordinate amount of time spent resolving hash collisions) but have never been able to pin it down with such a pure example. I'll admit that my skills in reading and making sense out of profiler output is pretty weak, but it looks to me that that's what is going on here. -- -- 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.
