On 19 March 2014 21:14, Alex Miller <a...@puredanger.com> wrote: > Rich just pushed a change to the String hashing to address this. We're > going to grab the string hashcode (which is cached after first call) and > murmur the result of that. This gives us constant time hashcode after first > call with better distribution for combinations in nested collections. Will > be in presumed RC2. >
If I understand correctly, this means that keywords and symbols use String.hashCode-based hashing in this commit. They are, however, capable of caching their Murmur3 hashes, so I was wondering if it might be better to have them use Murmur3 to hash name & ns? Rationale: murmuring hashCode results in collisions whenever hashCode does, plus possibly some additonal collisions if ints collide under murmur; murmur is better all around. Potential problems: not sure if things like case depend on symbol/keyword hashes being directly based on string hashes; hopefully not? Cheers, Michał > > > On Wednesday, March 19, 2014 11:26:51 AM UTC-5, Stefan Kamphausen wrote: >> >> >> >> On Wednesday, March 19, 2014 4:34:45 PM UTC+1, Alex Miller wrote: >>> >>> Thanks, this is all really useful. I would appreciate any more detailed >>> info. >>>> >>>> >>>> >> * No atoms, agents, refs >> * Almost purely functional plus logging and I/O >> * Multi-threaded using latest core.async with thread, no go >> * JVisualVM reports top methods in CPU sampling c.l.LazySeq.sval, >> c.c$promise$reify_6310.deref, c.l.LazySeq.seq no notable difference for me >> to see. >> >> A few experiments on two data-sets (dat1 and dat2) using either a call to >> set or to doall: >> >> Clojure Op Time (dat1) Time (dat1) Average dat1 Time (dat2) 1.5.1 set >> 19,1 19 19,05 323 1.5.1 doall 19 19,4 19,2 330 1.6.0-RC1 set 19,5 19,8 >> 19,65 350 1.6.0-RC1 doall 20,2 19,8 20 351 >> >> >> >> >> -- > 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. > -- 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.
