[Improvement] - Initial implementation of Concurrent::AtomicBoolean in pure Java

[lucasallan]

@jdantonio @pitr-ch Could you guys review this pull request?

[pitr-ch]

I think this should return result of compareAndSet rather than always nil.

[lucasallan]

There are some rules around it. I got some falling specs so now I'm fixing them. Thanks for pointing it out.

[coveralls]

Coverage decreased (-0.03%) to 91.73% when pulling fd794d9 on java-extension-for-atomic into 5e2ae69 on master.

[coveralls]

Coverage decreased (-0.12%) to 91.65% when pulling 39ca9db on java-extension-for-atomic into 5e2ae69 on master.

[coveralls]

Coverage decreased (-0.34%) to 91.43% when pulling ceeae16 on java-extension-for-atomic into 5e2ae69 on master.

[coveralls]

Coverage decreased (-0.34%) to 91.43% when pulling ceeae16 on java-extension-for-atomic into 5e2ae69 on master.

[coveralls]

Coverage decreased (-0.08%) to 91.69% when pulling ceeae16 on java-extension-for-atomic into 5e2ae69 on master.

[jdantonio]

@lucasallan Did you have an opportunity to run performance tests to verify that this approach is faster?

[lucasallan]

@jdantonio yes, I did and looks good (similar to the results we got on ref).
I'll post the results asap - I'm using my personal computer now and I don't have them.

[lucasallan]

But as you can see in this preview:

Java Version

~~~ JRuby version: 1.7.19
       user     system      total        real
Benchmarking Concurrent::AtomicFixnum#up...
   7.760000   0.050000   7.810000 (  7.375000)
Benchmarking Concurrent::AtomicFixnum#down...
   7.280000   0.030000   7.310000 (  7.275000)
Benchmarking Concurrent::AtomicFixnum#value...
   7.150000   0.030000   7.180000 (  7.154000)

JRuby Version

~~~ JRuby version: 1.7.19
       user     system      total        real
Benchmarking Concurrent::AtomicFixnum#up...
  24.120000   0.110000  24.230000 ( 23.738000)
Benchmarking Concurrent::AtomicFixnum#down...
  23.390000   0.070000  23.460000 ( 23.427000)
Benchmarking Concurrent::AtomicFixnum#value...
  21.390000   0.120000  21.510000 ( 21.655000)

Ruby code:

require 'concurrent'
require 'benchmark'

NUM = 50_000_000

if defined? JRUBY_VERSION
  puts "~~~ JRuby version: #{JRUBY_VERSION}"

  Benchmark.bm do |stats|
    e = Concurrent::AtomicFixnum.new()

    puts "Benchmarking Concurrent::AtomicFixnum#up..."
    stats.report do
      NUM.times { e.up }
    end

    puts "Benchmarking Concurrent::AtomicFixnum#down..."
    stats.report do
      NUM.times { e.down }
    end

    puts "Benchmarking Concurrent::AtomicFixnum#value..."
    stats.report do
      NUM.times { e.value }
    end
  end

end

[jdantonio]

Awesome! Thank you!

[pitr-ch]

It could also be getRuntime().newBoolean(atomicBoolean.compareAndSet(false, true)).