More performance explorations

[Rémi Forax]

On 06/03/2011 04:37 AM, John Rose wrote:
> Thanks; I'll look at your dump later tonight.
>
> If the problem is friction from interface casts, we can probably 
> remove them.  It's hard to figure out how they are getting in, though. 
>  It happens when IRubyObject interconverts with Object.  Are you doing 
> it, or is it coming from inside the java.lang.invoke classes?  That's 
> the first question.  It probably comes from an asType, but some asType 
> calls are implicit within the 292 API.  What asType calls 
> (was convertArguments) are in your code?
>
> Key fact:  asType/convertArguments used to allow interfaces a free 
> unchecked pass into and out of Object.  Now only explicitCastArguments 
> does this.  If you convert between an interface and Object, you'll get 
> a real checkcast (and a potential CCE) from asType.
>
> Try changing convertArguments globally to explicitCastArguments and 
> see what happens.

Semantically there aren't equivalent but it should not be a problem
if you don't use asType to do an unboxing conversions
e.g. Integer or Object -> int

if the object is null asType throws a NPE but explicitCastArguments 
returns 0.

>
> -- John

Rémi