RFR: 8258912: Remove JVM options CountJNICalls and CountJVMCalls

[David Holmes]

On Tue, 12 Jan 2021 15:17:52 GMT, Harold Seigel <hseigel at openjdk.org> wrote:

> Please review this change to remove the old non-product JVM -XX flags CountRuntimeCalls, CountJNICalls, CountJVMCalls, and CountRemovableExceptions.  Additionally, this change removes non-product flag WarnOnStalledSpinLock because, as a result of this change, it is no longer used.
> 
> The change was tested with Mach5 tiers 1-2 on Linux, Mac OS, and Windows, and tiers 3-5 on Linux x64.
> 
> Thanks, Harold

Hi Harold,

The call counters seem like useful statistics to me, though ones that may only be checked during specific types of development work. I think some consultation may be in order here rather than "take it away and see if anyone complains".

At a minimum I'd like to know whether our benchmarking/optimisation experts ever utilise these when figuring out code changes - paging @cl4es and @shipilev  :)

Thanks,
David

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PR: https://git.openjdk.java.net/jdk/pull/2050