RFR: 8232651: Add implementation of os::processor_id() for Windows

[Bob Vandette]

Have you considered using GetCurrentProcessorNumberEx so you can handle a system with more than 64 CPUs?

Bob.


> On Oct 21, 2019, at 10:23 AM, Stefan Karlsson <stefan.karlsson at oracle.com> wrote:
> 
> Hi all,
> 
> Please review this patch to add an implementation of os::processor_id() for Windows.
> 
> https://cr.openjdk.java.net/~stefank/8232651/webrev.01/
> https://bugs.openjdk.java.net/browse/JDK-8232651
> 
> We need an implementation of this function on Windows, to be able to run ZGC there.
> 
> Note that GetCurrentProcessorNumber only "returns the processor number within the processor group to which the logical processor is assigned". AFAICT, there's no support for multi-groups in HotSpot, and therefore this seems like an adequate function to use.
> 
> See this page for more information about processor groups:
> https://docs.microsoft.com/en-us/windows/win32/procthread/processor-groups
> 
> Thanks,
> StefanK