RFR: 8255959: Timeouts in VectorConversion tests

[Paul Sandoz]

On Thu, 5 Nov 2020 16:59:57 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> We observed many timeouts in the following test/jdk/jdk/incubator/vector tests:
> Vector128ConversionTests.java
> Vector256ConversionTests.java
> Vector512ConversionTests.java
> Vector64ConversionTests.java
> VectorMaxConversionTests.java
> Some machines don't support vector instructions or fewer of them and C2 uses slower alternatives.
> 
> Maybe there are options to make the tests faster, but I just propose to use a larger timeout value for now.

I have not observed such timeouts in our test infrastructure, but was wondering if this may cause such issues. Perhaps PPC does not support the conversion intrinsics?

The timeout value is quite high, 1800 (i cannot recall what the default is). Ideally we should split this test per species. I regret that this test is not produced from a template.

Would you mind first if we can try a quick experiment to reduce the time taken? In `AbstractVectorConversionTest` there is a loop using an upper bound of `INVOC_COUNT`, perhaps if any of the species input to the relevant methods have a length > the length of the corresponding preferred species, then we can reduce the loop count.

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PR: https://git.openjdk.java.net/jdk/pull/1079