Performance of memory var handles in hot loops

[Paul Sandoz]

I updated the Vector API JEP to capture that the API be updated to support MemorySegments, when it exits incubation (dunno if possible early with a dependence on an incubator module).

Paul. 

> On Apr 8, 2020, at 3:52 AM, Antoine Chambille <ach at activeviam.com> wrote:
> Yes the vector API works well on native memory exposed as byte buffers,
> performance is better than scalar but not yet on par with the vector API on
> arrays. I have actually tried it recently on the same kind of benchmark.
> http://mail.openjdk.java.net/pipermail/panama-dev/2020-March/007786.html.
> That's when John Rose mentioned that the vector API would support memory
> segments, and hinted that it would be the preferred way to use the vector
> API on native memory.
> 
> Cheers,
> -Antoine
> 
> 
> 
> 
> 
> 
> On Wed, Apr 8, 2020 at 12:21 PM Maurizio Cimadamore <
> maurizio.cimadamore at oracle.com> wrote:
> 
>> 
>> On 08/04/2020 08:58, Antoine Chambille wrote:
>>> I'm not too worried about that because the panama vector API is
>>> coming. By the way is there already a prototype of the Vector API that
>>> works on memory segments?
>> 
>> No, I think ATM the vector API doesn't have a way to load a vector from
>> a memory segment. That said, IIRC it has ways to load it from a
>> ByteBuffer and you can turn the segment into a BB (provided it fits into
>> a 32-bit size).
>> 
>> I did some experiments in the past about bridging the two APIs, the
>> results I got were a bit hit and miss but it was a long time ago - maybe
>> it's time to do another attempt.
>> 
>> Maurizio
>> 
>>