On Tue, Dec 13, 2011 at 4:52 PM, Clemens Eisserer <linuxhi...@gmail.com> wrote: > Hmm, from what I understand, hotspot's interpreter is already > "super-hot" right after startup. > Whereas JRuby's interpreter is jvm bytecode that needs to be compiled > by a compiler, hotspot's interpreter is *hand-tuned* low-level > assembly.
This is all true. The subtle part is that our interpreter runs faster when jitted by the JVM than the JVM's interpreter can run compiled Ruby code. Here's "fib", first interpreted (by JRuby) but with the interpreter jitted (by the JVM), and second compiled (by JRuby) but interpreted (by the JVM): system ~/projects/jruby $ jruby -X-C bench/bench_fib_recursive.rb 5 35 3.179000 0.000000 3.179000 ( 3.150000) 3.650000 0.000000 3.650000 ( 3.650000) 3.739000 0.000000 3.739000 ( 3.740000) 3.733000 0.000000 3.733000 ( 3.733000) 3.778000 0.000000 3.778000 ( 3.778000) system ~/projects/jruby $ jruby -X+C -J-Xint bench/bench_fib_recursive.rb 5 35 75.825000 0.000000 75.825000 ( 75.805000) 75.994000 0.000000 75.994000 ( 75.994000) Now this isn't *quite* fair since more than just the Ruby code is running interpreted in the second case, but it illustrates a point...our interpreter actually performs surprisingly well compared to fully-interpreted Java, and as a result having Ruby code interpret first often leads to things "warming up" more quickly (with the alternative being to only ever run compiled Ruby code, but accept it will be "cold" for 10000 calls). - Charlie _______________________________________________ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
