The volatile construct seems very useful in some particular cases! I have been missing "ugly-mutable" variables for things such as certain types of heaps/queues or write-intensive, slightly probabilistic stuff where one missed write doesn't matter that much.
For people who don't have a Java background, I just want to point the very useful package java.util.concurrent.atomic, in which one can find gems such as AtomicLong, which is almost unbeatable as a counter. An example in which an AtomicLong is about three times quicker than an atom: https://gist.github.com/claj/6711556#file-countertest-clj Javadoc for AtomicLong: http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/AtomicLong.html In the sake of completeness, Linus 2014-09-11 11:06 GMT+02:00 Frantisek Sodomka <fsodo...@gmail.com>: > Using my timings macro: > https://gist.github.com/fsodomka/5890711 > > I am getting that: > - creation & derefing is 60% faster > - swapping is 25% faster > - resetting is about the same > > > ;;;;;;;;;; volatile vs. atom ;;;;;;;;;; > > (report > (timings 1e7 > (deref (volatile! 42)) > (deref (atom 42)))) > > ; | :expr | :time | :ratio | :perc | > ; |------------------------+-----------+--------+-------| > ; | (deref (volatile! 42)) | 30.688238 | 1.0 | 39.81 | > ; | (deref (atom 42)) | 77.081141 | 2.51 | 100.0 | > > > (report > (let [v (volatile! 42) > a (atom 42)] > (timings 1e7 > (vswap! v inc) > (swap! a inc)))) > > ; | :expr | :time | :ratio | :perc | > ; |----------------+------------+--------+-------| > ; | (vswap! v inc) | 136.052946 | 1.0 | 75.08 | > ; | (swap! a inc) | 181.218748 | 1.33 | 100.0 | > > > (report > (let [v (volatile! 42) > a (atom 42)] > (timings 1e7 > (vreset! v 10) > (reset! a 10)))) > > ; | :expr | :time | :ratio | :perc | > ; |----------------+-----------+--------+-------| > ; | (reset! a 10) | 98.755318 | 1.0 | 96.69 | > ; | (vreset! v 10) | 102.13944 | 1.03 | 100.0 | > > > > > On Thursday, September 11, 2014 6:18:08 AM UTC+2, puzzler wrote: >> >> I'm curious: how much faster are volatiles than atoms? >> >> -- > 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.
