8234805: (dc) Remove JNI upcall from DatagramChannel.receive implementation

[Chris Hegarty]

This looks like a nice improvement.

> On 26 Nov 2019, at 13:22, Alan Bateman <Alan.Bateman at oracle.com> wrote:
> 
> This is a patch to replace the JNI upcall in the implementation of DatagramChannel.receive so that the sender SocketAddress is created in Java rather in the native method. This is the issue that was discussed here last year [1]. The replacement marginally improves the single source case, significantly improves the multiple source case.  I've created an issue to add tests to the micro benchmark suite

While there is a separate JIRA tracking some potential new benchmark tests in this area, is it possible to share what you currently have? that demonstrates the marginal improvement for the single source case. I would like to see the impact of the removal of the single cached address.

-Chris.