Good news, bad news

[Charles Oliver Nutter]

On Fri, May 20, 2011 at 1:07 AM, Ola Bini <ola.bini at gmail.com> wrote:
>> Try -XX:+UnlockDiag* -XX:-UseRicochetFrames for differential testing.
>>
>> If you can find a microbenchmark which shows differential slowdown, we can debug it.
>
> When trying the above all my tests fail with this:
>  java.lang.RuntimeException: java.lang.InternalError: NYI

Same here.

Reproducing it is pretty easy...

* Clone JRuby: git clone https://github.com/jruby/jruby.git
* Build JRuby: cd jruby ; ant
* Run benchmarks: bin/jruby bench/bench_fib_recursive.rb 10 35

There are many benchmarks under the bench dir, almost all of which
show this degradation. You can disable invokedynamic use in JRuby by
passing -Xcompile.invokedynamic=false, as seen here:


~/projects/jruby ➔ jruby -Xcompile.invokedynamic=false
bench/bench_fib_recursive.rb 5 35
WARNING: Both jruby-complete.jar and jruby.jar are present in the
'lib' directory. Will use jruby.jar
9227465
  1.698000   0.000000   1.698000 (  1.645000)
9227465
  1.352000   0.000000   1.352000 (  1.352000)
9227465
  1.364000   0.000000   1.364000 (  1.364000)
9227465
  1.344000   0.000000   1.344000 (  1.344000)
9227465
  1.336000   0.000000   1.336000 (  1.336000)

~/projects/jruby ➔ jruby -Xcompile.invokedynamic=true
bench/bench_fib_recursive.rb 5 35
WARNING: Both jruby-complete.jar and jruby.jar are present in the
'lib' directory. Will use jruby.jar
9227465
  3.182000   0.000000   3.182000 (  3.120000)
9227465
  3.019000   0.000000   3.019000 (  3.019000)
9227465
  3.195000   0.000000   3.195000 (  3.195000)
9227465
  3.163000   0.000000   3.163000 (  3.163000)
9227465
  3.656000   0.000000   3.656000 (  3.656000)

I'm sure something's just broken...this benchmark was easily almost 2x
faster than the non-invokedynamic version just a few days ago, and
it's now 2-3x slower than non-indy logic.

I'm going to be online all day, standing by to help in any way I can.
I did do a quick LogCompilation last night and the main thing I
noticed was that while it seemed like handles are inlining, the
eventual DMH does not inline. That would explain some of the perf
degradation, I think...but hopefully not all of it.

Whatever you need me to run or whatever information...let me know.

ALSO...I got the same error as Ola when running JRuby with a
standalone jar file:

~/projects/jruby ➔ java -jar lib/jruby-complete.jar bench/bench_fib_recursive.rb
MethodHandle.java:-1:in `invokeExact': java.lang.NoClassDefFoundError:
org/jruby/runtime/ThreadContext
	from MethodHandle.java:-1:in `invokeExact'
	from bench/bench_fib_recursive.rb:7:in `method__0$RUBY$fib_ruby'
	from bench/bench_fib_recursive.rb:7:in `method__0$RUBY$fib_ruby'
	from bench/bench_fib_recursive.rb:7:in `method__0$RUBY$fib_ruby'
	from bench/bench_fib_recursive.rb:7:in `method__0$RUBY$fib_ruby'

As in Ola's case, ThreadContext is a core JRuby class. I do *not* get
this error when JRuby is loaded from the bootstrap classloader, so I
imagine there's some mix-up with generated bytecode and the
classloaders that that bytecode gets loaded into.

- Charlie