Benchmarking ^char type-hint vs (char)

char-benchmark-results.txt

====== Benching (Character/isLetter ^char c) ====== 
WARNING: Final GC required 3.956775511289807 % of runtime
amd64 Linux 3.2.0-48-generic 2 cpu(s)
Java HotSpot(TM) 64-Bit Server VM 23.21-b01
Runtime arguments: -XX:+TieredCompilation -XX:TieredStopAtLevel=1 -Dclojure.compile.path=/tmp/oneoff/classes -Doneoff.version=0.1 -Dfile.encoding=UTF-8 -Dclojure.debug=false
Evaluation count : 5580540 in 60 samples of 93009 calls.
      Execution time sample mean : 11.046857 µs
             Execution time mean : 11.046903 µs
Execution time sample std-deviation : 24.758483 ns
    Execution time std-deviation : 24.947300 ns
   Execution time lower quantile : 10.982341 µs ( 2.5%)
   Execution time upper quantile : 11.089820 µs (97.5%)
                   Overhead used : 22.302964 ns

Found 4 outliers in 60 samples (6.6667 %)
	low-severe	 3 (5.0000 %)
	low-mild	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers

====== Benching (Character/isLetter (char c)) ====== 
amd64 Linux 3.2.0-48-generic 2 cpu(s)
Java HotSpot(TM) 64-Bit Server VM 23.21-b01
Runtime arguments: -XX:+TieredCompilation -XX:TieredStopAtLevel=1 -Dclojure.compile.path=/tmp/oneoff/classes -Doneoff.version=0.1 -Dfile.encoding=UTF-8 -Dclojure.debug=false
Evaluation count : 5460840 in 60 samples of 91014 calls.
      Execution time sample mean : 11.294136 µs
             Execution time mean : 11.294148 µs
Execution time sample std-deviation : 26.541266 ns
    Execution time std-deviation : 26.966371 ns
   Execution time lower quantile : 11.226729 µs ( 2.5%)
   Execution time upper quantile : 11.340594 µs (97.5%)
                   Overhead used : 22.302964 ns

Found 10 outliers in 60 samples (16.6667 %)
	low-severe	 2 (3.3333 %)
	low-mild	 3 (5.0000 %)
	high-mild	 4 (6.6667 %)
	high-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers

char-benchmark.clj

;; INSTRUCTIONS: add lein oneoff (https://github.com/mtyaka/lein-oneoff) to your profiles.clj
;; and run "lein oneoff char-benchmark.clj"

#_(defdeps [[org.clojure/clojure "1.5.1"]
            [criterium "0.4.1"]])

(use 'criterium.core)
(def data "abcdefghijklmnopqrstuvwxyz1234567890")

(println "====== Benching (Character/isLetter ^char c) ====== ")
(bench (dorun (filter #(Character/isLetter ^char %) data)) :verbose)

(println)

(println "====== Benching (Character/isLetter (char c)) ====== ")
(bench (dorun (filter #(Character/isLetter (char %)) data)) :verbose)

Twitter discussion: https://twitter.com/puredanger/status/353924017662595075