Verified that I receive the same result patterns as you on my machine. One other possibility outside of what you have already mentioned would be something JIT-related. Perhaps there is an optimization that can be performed if the locking sections of the code are in another function but otherwise no, but I'm not sure how that dovetails with Clojure' fn compilation.
On Friday, November 1, 2013 11:53:12 AM UTC-7, Michael Blume wrote: > > 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.
