Since 1.6 alpha is out, I reran the tests with that -- basically the same results.
On Friday, November 1, 2013 11:34:15 AM UTC-7, Michael Blume wrote: > > https://github.com/MichaelBlume/perf-test > > (ns perf-test > (:use (criterium core)) > (:gen-class)) > > (def o (Object.)) > > (defn foo [x] > (if (> x 0) > (inc x) > (do > (monitor-enter o) > (let [res (dec x)] > (monitor-exit 0) > res)))) > > (defn bar [x] > (if (> x 0) > (inc x) > (dec x))) > > (defn locking-part [x l] > (monitor-enter l) > (let [res (dec x)] > (monitor-exit l) > res)) > > (defn baz [x] > (if (> x 0) > (inc x) > (locking-part x o))) > > (defn -main [] > (println "benching foo") > (bench (foo 5) :verbose) > (println "benching bar") > (bench (bar 5) :verbose) > (println "benching baz") > (bench (baz 5) :verbose) > (println "done benching")) > > > > I'm only ever calling these functions with positive values, so the > monitor-enter branch should never be entered. Nevertheless, the performance > of foo is much worse than bar or baz. > > The best guess I've got is that the fact that lock-taking is involved somehow > changes how the function is compiled, somehow making the function slower. If > the practical upshot is that I shouldn't write functions that only sometimes > lock -- that the locking part of a function should always be its own function > -- then I can do that, but I'm curious why. > > $ lein uberjar > Compiling perf-test > Created /Users/mike/perf-test/target/perf-test-0.1.0-SNAPSHOT.jar > Created /Users/mike/perf-test/target/perf-test-0.1.0-SNAPSHOT-standalone.jar > $ java -jar -server target/perf-test-0.1.0-SNAPSHOT-standalone.jar > benching foo > WARNING: Final GC required 1.5974571326266802 % of runtime > x86_64 Mac OS X 10.8.3 4 cpu(s) > Java HotSpot(TM) 64-Bit Server VM 24.0-b28 > Runtime arguments: > Evaluation count : 391582560 in 60 samples of 6526376 calls. > Execution time sample mean : 167.426696 ns > Execution time mean : 167.459429 ns > Execution time sample std-deviation : 4.079466 ns > Execution time std-deviation : 4.097819 ns > Execution time lower quantile : 160.742869 ns ( 2.5%) > Execution time upper quantile : 175.453376 ns (97.5%) > Overhead used : 1.634996 ns > > Found 2 outliers in 60 samples (3.3333 %) > low-severe 2 (3.3333 %) > Variance from outliers : 12.5602 % Variance is moderately inflated by > outliers > benching bar > x86_64 Mac OS X 10.8.3 4 cpu(s) > Java HotSpot(TM) 64-Bit Server VM 24.0-b28 > Runtime arguments: > Evaluation count : 2174037300 in 60 samples of 36233955 calls. > Execution time sample mean : 26.068923 ns > Execution time mean : 26.066422 ns > Execution time sample std-deviation : 0.887937 ns > Execution time std-deviation : 0.916861 ns > Execution time lower quantile : 23.996763 ns ( 2.5%) > Execution time upper quantile : 27.911936 ns (97.5%) > Overhead used : 1.634996 ns > > Found 3 outliers in 60 samples (5.0000 %) > low-severe 1 (1.6667 %) > low-mild 1 (1.6667 %) > high-mild 1 (1.6667 %) > Variance from outliers : 22.1874 % Variance is moderately inflated by > outliers > benching baz > x86_64 Mac OS X 10.8.3 4 cpu(s) > Java HotSpot(TM) 64-Bit Server VM 24.0-b28 > Runtime arguments: > Evaluation count : 2270676660 in 60 samples of 37844611 calls. > Execution time sample mean : 25.834142 ns > Execution time mean : 25.837429 ns > Execution time sample std-deviation : 0.718382 ns > Execution time std-deviation : 0.729431 ns > Execution time lower quantile : 24.837925 ns ( 2.5%) > Execution time upper quantile : 27.595781 ns (97.5%) > Overhead used : 1.634996 ns > > Found 4 outliers in 60 samples (6.6667 %) > low-severe 2 (3.3333 %) > low-mild 2 (3.3333 %) > Variance from outliers : 15.7591 % Variance is moderately inflated by > outliers > done benching > > -- -- 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.
