On Fri, 4 Apr 2025 22:52:24 GMT, Vladimir Ivanov <vliva...@openjdk.org> wrote:
> Migrate Vector API math library (SVML and SLEEF) linkage from native code (in
> JVM) to Java FFM API.
>
> Since FFM API doesn't support vector calling conventions yet, migration
> affects only symbol lookup for now. But it still enables significant
> simplifications on JVM side.
>
> The patch consists of the following parts:
> * on-demand symbol lookup in Java code replaces eager lookup from native
> code during JVM startup;
> * 2 new VM intrinsics for vector calls (support unary and binary shapes)
> (code separated from unary/binary vector operations);
> * new internal interface to query supported CPU ISA extensions
> (`jdk.incubator.vector.CPUFeatures`) used for CPU dispatching.
>
> `java.lang.foreign` API is used to perform symbol lookup in vector math
> library, then the address is cached and fed into corresponding JVM intrinsic,
> so C2 can turn it into a direct vector call in generated code.
>
> Once `java.lang.foreign` supports vectors & vector calling conventions, VM
> intrinsics can go away.
>
> Performance is on par with original implementation (tested with
> microbenchmarks on linux-x64 and macosx-aarch64).
>
> Testing: hs-tier1 - hs-tier6, microbenchmarks (on linux-x64 and
> macosx-aarch64)
>
> Thanks!
Few questions?
src/jdk.incubator.vector/share/classes/jdk/incubator/vector/CPUFeatures.java
line 60:
> 58: }
> 59:
> 60: public static class X64 {
Should we create `src/jdk.incubator.vector/cpu/` for CPU specific information?
As separate refactoring.
src/jdk.incubator.vector/share/classes/jdk/incubator/vector/VectorMathLibrary.java
line 100:
> 98:
> 99: /**
> 100: * Naming convention in SVML vector math library.
Does this library has code for all AVX configurations?
-------------
PR Review: https://git.openjdk.org/jdk/pull/24462#pullrequestreview-2747510895
PR Review Comment: https://git.openjdk.org/jdk/pull/24462#discussion_r2031654383
PR Review Comment: https://git.openjdk.org/jdk/pull/24462#discussion_r2031657213
