Status of indy opto, update releases...

[Charles Oliver Nutter]

On Thu, Mar 29, 2012 at 10:46 AM, Christian Thalinger
<christian.thalinger at oracle.com> wrote:
>> * indy classloading headaches
>>
>> The old NoClassDefFound problems seem to have gone away (or I just
>> haven't been able to trigger them) but more recently I reported on
>> this list about LinkageErrors that seemed to be caused by indy. I
>> eventually patched around them, forcing more classes to be created and
>> isolated...but I don't see how I could have been at fault in my code.
>
> This should all disappear in our new implementation (meth-lazy patches in the repository) because of the way we handle signatures.  Unfortunately the compiler support isn't complete yet (inlining is not perfect yet) so it may be a pain to test it (because it's slow) but the code executed in the interpreter and in the compilers is the same.  And so should trigger the same errors (if there are any).

Ok, I'm happy to start testing it out to shake loose any issues. I
will assume I shouldn't report performance degradation right now.

>> The performance is bad enough that I may have to install some tiering
>> logic into JRuby's compiler so that methods over a certain size don't
>> use invokedynamic at all. It will be messy.
>
> That performance problem also disappears with the meth-lazy stuff.

Excellent! I have heled off on a few additional uses of invokedynamic
in JRuby because of the degradation, but I'm looking forward to
turning those on.

> 7u4 is pretty much closed.  The newer stuff has to wait for a future update release.

Ahh, that's too bad. Hopefully u4 will be sufficient for folks
interested in trying JRuby + invokedynamic and u6 will help anyone who
runs into perf issues or bugs in u4.

At this point I'm debating options for JRuby 1.7. We've delayed it a
long time, and need to get it released, but the invokedynamic story is
still a bit of a mixed bag. I don't want to have indy logic disabled
by default in JRuby 1.7, but we'll consider that possibility as we
approach a final release in the next couple months.

> I try to polish the meth-lazy.jit patch a bit so that it works and running tests isn't awfully slow.  Let's see what I can come up with.  I'll keep you posted.

Excellent! I will be standing by :)

Would it be possible to get a paragraph describing how the new MH
logic differs from the old logic? It might be of some interest to
attendees at my deep-dive session at JAX next month.

- Charlie

- Charlie