RFC: Untangle native libraries and the JVM: SVML, SLEEF, and libsimdsort

[Vladimir Ivanov]

>>> - There is an open bug to adjust the simd sort behavior on AMD zen 4 cores due to poor performance of an AVX 512 instruction. The simplest solution is to fall back to AVX2. That may be simpler to manage in Java? (I was looking at the HotSpot code).
>>
>> For now, the patch guards AVX512 entries with VM.isIntelCPU() check. In order to distinguish between AMD Zen 4 and 5, either a new platform-sensing check is needed or reimplementation of x86-specific platform sensing in Java on top of CPUID info.
>>
> 
> Probably best just to update as required. (Also I don’t seem anything in the HotSpot code to determine the AMD zen core version.)

Yes, it's not implemented yet. But there are enough examples for Intel 
chips to see how it will look like (e.g., is_intel_skylake() or 
is_knights_family()).

> Any general CPU vendor/model solution seems a little more challenging than that of surfacing up the CPU feature set as a string. Note that the System.getProperties() surfaces up “os.arch”. A more general solution could add further properties for the CPU?

Personally, I'm not a fan of "stringy" APIs. It may look convenient at 
first, but it suffers from deficiencies of both approaches. I would 
prefer to use a strongly typed platform-specific API instead (an 
equivalent of VM_Version class in hotspot).

Best regards,
Vladimir Ivanov