From: Sander Land <sander.land@...>
Date: 2008-01-10T19:40:00+09:00
Subject: Re: [ANN] JRuby 1.1 RC 1 Released

On Jan 10, 2008 2:40 AM, Charles Oliver Nutter <charles.nutter@sun.com> wrote:
>
> Sander Land wrote:
> > On Jan 10, 2008 12:35 AM, Charles Oliver Nutter <charles.nutter@sun.com> wrote:
> >> What Java version is this?
> >>
> >> - Charlie
> >
> > $ java -version
> > java version "1.6.0_03"
> > Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
> > Java HotSpot(TM) Client VM (build 1.6.0_03-b05, mixed mode, sharing)
>
> Can I see the benchmark? I'd like to investigate why it's not still
> faster than 1.8, even after -O3.
>
> - Charlie
>

The benchmark depends on a ~1500 line library. I can send you an email
when I have the next release (in a few days), but I'm not sure if
digging through the library would be an effective use of your time.
The benchmark show that JRuby is a little slower, independent of the
specific selection, crossover or mutation algorithm used. The only
thing in the inner loop that all of these algorithms have in common
are the fitness evaluations.

This script takes just the fitness evaluations, and it does seem the
problem is in this code:

require 'enumerator'
class RR
  attr_accessor :genes
  def initialize
    @genes = Array.new(64){rand(2)}
  end
  def fitness
    1 + genes.enum_slice(8).find_all{|e| e.all?{|x|x==1} }.size
  end
end

require 'benchmark'
Benchmark.bmbm{|x|
x.report{ 200_000.times{ RR.new.fitness } }
}

1.8 -O3
       user     system      total        real
  15.350000   0.160000  15.510000 ( 16.929467)

1.9 -O3, (with alias :enum_slice :each_slice)
       user     system      total        real
   9.530000   0.000000   9.530000 (  9.530245)

JRuby -C
       user     system      total        real
  35.701000   0.000000  35.701000 ( 35.701000)

JRuby +C
       user     system      total        real
  32.980000   0.000000  32.980000 ( 32.981000)

I also ran one of my other benchmarks (a function optimization test)
which uses the same library.
1.8 compiled : 81.39
1.9 compiled : 43.79
JRuby -C: 95.28
JRuby +C: 63.98