boxing + unboxing a VT is not a no-op ? (original) (raw)

forax at univ-mlv.fr forax at univ-mlv.fr
Mon Jul 16 20:20:53 UTC 2018

----- Mail original -----

De: "Tobias Hartmann" <tobias.hartmann at oracle.com> À: "Remi Forax" <forax at univ-mlv.fr> Cc: "valhalla-dev" <valhalla-dev at openjdk.java.net> Envoyé: Lundi 16 Juillet 2018 16:16:51 Objet: Re: boxing + unboxing a VT is not a no-op ?

Thanks Remi!

When trying to re-produce, I'm hitting JDK-8207346. I'll fix that first and then investigate the performance issue.

Ok, cool !

Tobias

Rémi

On 13.07.2018 15:11, forax at univ-mlv.fr wrote: the source code is here: https://github.com/forax/valuetype-lworld/blob/master/src/test/java/fr.umlv.valuetype/fr/umlv/valuetype/perf/ReifiedListBenchMark.java#L118

the instructions about how to build are here: https://github.com/forax/valuetype-lworld Rémi ----- Mail original ----- De: "Tobias Hartmann" <tobias.hartmann at oracle.com> À: "Remi Forax" <forax at univ-mlv.fr>, "valhalla-dev" <valhalla-dev at openjdk.java.net> Envoyé: Vendredi 13 Juillet 2018 14:43:10 Objet: Re: boxing + unboxing a VT is not a no-op ?

Hi Remi,

thanks for reporting. Could you please provide the full source code so we can have a closer look? Best regards, Tobias On 12.07.2018 20:43, Remi Forax wrote: Hi guys, it seems that operations likes VT -> Object -> VT are not optimized has being a no-op.

with IntBox being a value type that wrap an int, this code is slow (not very slow, i.e not interpreter slow) public int valuelistintboxinnervalueinlinedreduce() { _ByValue class Adder implements BiFunction<IntBox, IntBox, IntBox> { private final boolean nonEmpty; Adder() { nonEmpty = false; throw new AssertionError(); } public IntBox apply(IntBox acc, IntBox element) { return acc.add(element); } } _BiFunction<IntBox, IntBox, IntBox> mapper = MakeDefault Adder(); var sum = IntBox.zero(); int size = valueList.size(); for(int i = 0; i < size; i++) { sum = mapper.apply(sum, valueList.get(i)); } return sum.intValue(); } while this code is fast (more than 10 times faster) public int valuelistintboxinlinedreduce() { var sum = IntBox.zero(); int size = valueList.size(); for(int i = 0; i < size; i++) { sum = sum.add(valueList.get(i)); } return sum.intValue(); } the difference is that instead of calling add on an IntBox to do the addition, i used an anonymous value class which implement a functional interface which used Objects. (valueList is just an array of IntBox wrapped in a value type). regards, Rémi

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