RFR: 8317976: Optimize SIMD sort for AMD Zen 4 [v2]

[Srinivas Vamsi Parasa]

On Mon, 17 Mar 2025 17:23:26 GMT, Rohit Arul Raj <rraj at openjdk.org> wrote:

>> src/hotspot/cpu/x86/stubGenerator_x86_64.cpp line 4318:
>> 
>>> 4316:   // Load x86_64_sort library on supported hardware to enable SIMD sort and partition intrinsics
>>> 4317: 
>>> 4318:   if (VM_Version::supports_avx512dq() || VM_Version::supports_avx2()) {
>> 
>> Shouldn't you check for `VM_Version::supports_avx512_simd_sort()` here as well?
>
> The above condition will hold for all AMD processors. Only for Zen4, even though AVX512 is supported, we want to pick AVX2 version of SIMD sort (due to the regression) which is handled by the code below:
> 
> snprintf(ebuf_, sizeof(ebuf_), **VM_Version::supports_avx512_simd_sort()** ? "avx512_sort" : "avx2_sort");

Thanks for the clarification!

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PR Review Comment: https://git.openjdk.org/jdk/pull/24053#discussion_r1999292833