RFR (S) CR 7177472: JSR292: MethodType interning penalizes scalability

[Christian Thalinger]

On Jun 10, 2013, at 8:47 AM, Aleksey Shipilev <aleksey.shipilev at oracle.com> wrote:

> On 06/09/2013 12:17 AM, Peter Levart wrote:
>> In case the loop retries, there's no need to construct another WeakEntry...
>> 
>>            T interned;
>>             WeakEntry<T> e = new WeakEntry<>(elem, stale);
>>            do {
>>                expungeStaleElements();
>>                WeakEntry<T> exist = map.putIfAbsent(e, e);
>>                interned = (exist == null)? elem: exist.get();
>>            } while (interned == null);
>>            return interned;
> 
> That's right, thanks!
> 
> The update is here:
>  http://cr.openjdk.java.net/~shade/7177472/webrev.02/
> 
> Testing:
>  - Linux x86_64 builds OK
>  - Linux x86_64 java/lang/invoke/ jtreg passes OK
>  - The microbenchmark scores in the original note are still the same

This looks good to me.  One thing I mentioned in the bug report is that V8's RegExp shows some MethodType related methods in a -Xprof run:

     Compiled + native Method 
 11.9% 2455 + 0 java.util.regex.Pattern$GroupTail.match 
 11.5% 2382 + 0 java.util.regex.Pattern$Start.match 
 10.2% 2110 + 0 java.util.regex.Pattern$5.isSatisfiedBy 
  8.5% 1765 + 0 java.util.regex.Pattern$Branch.match 
  7.1% 1461 + 0 java.lang.invoke.MethodType$WeakInternSet.get 
  3.4% 709 + 0 java.util.regex.Pattern$CharProperty.match 
  2.9% 597 + 1 java.lang.invoke.MethodType.makeImpl 

Could you run RegExp with Nashorn again with and without your changes?

-- Chris

> 
> -Aleksey.
>