RFR: 8272861: Add a micro benchmark for vector api

[Aleksey Shipilev]

On Mon, 23 Aug 2021 23:18:28 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

> This pull request adds a micro benchmark for Vector API.
> The Black Scholes algorithm is implemented with and without Vector API.
> We see about ~6x gain with Vector API for this micro benchmark using 256 bit vectors.

Some benchmark comments.

test/micro/org/openjdk/bench/jdk/incubator/vector/BlackScholes.java line 91:

> 89:     static float A4 = -1.821255978f;
> 90:     static float A5 = 1.330274429f;
> 91:     static float PI = (float)Math.PI;

Want to make these `static final`?

test/micro/org/openjdk/bench/jdk/incubator/vector/BlackScholes.java line 134:

> 132: 
> 133:     @Benchmark
> 134:     public void scalar_black_scholes(Blackhole bh) {

So there is a `Blackhole` argument here, but what is actually blackholed? AFAICS, stores to `call` and `put` are roughly okay to avoid dead-code elimination on these paths.

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PR: https://git.openjdk.java.net/jdk/pull/5234