[foreign-abi] RFR: 8251048: Add some upcall benchmarks

[Maurizio Cimadamore]

On Tue, 4 Aug 2020 14:18:38 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Hi,
> 
> This patch adds a few basic upcall benchmarks to measure the call overhead between JNI and panama, in order to track
> future progress to optimize upcalls. (Currently panama is slower, because we basically do JNI + extras, but the code
> needed to get there is significantly simpler for panama's API).  I've also added jvm args to `@Fork` annotations for
> all the benchmarks, so they don't have to be passed on the command line (only --enable-preview has to be passed
> currently, which is a temporary workaround for another issue).  I've also removed the NO_SPEC variants from the
> CallOverhead benchmark, since the flag no longer exists. We also weren't covering all the combinations of USE_SPEC and
> USE_INTRINSICS. Rather than adding benchmark methods for each combination, the same results can be found by setting the
> relevant system properties on the command line, which keeps the code simpler.  Thanks, Jorn

Looks very good thanks!

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Marked as reviewed by mcimadamore (Committer).

PR: https://git.openjdk.java.net/panama-foreign/pull/277