RFR: 8338023: Support two vector selectFrom API [v3]
Jatin Bhateja
jbhateja at openjdk.org
Wed Aug 21 16:42:44 UTC 2024
> Hi All,
>
> As per the discussion on panama-dev mailing list[1], patch adds the support for following new two vector permutation APIs.
>
>
> Declaration:-
> Vector<E>.selectFrom(Vector<E> v1, Vector<E> v2)
>
>
> Semantics:-
> Using index values stored in the lanes of "this" vector, assemble the values stored in first (v1) and second (v2) vector arguments. Thus, first and second vector serves as a table, whose elements are selected based on index value vector. API is applicable to all integral and floating-point types. The result of this operation is semantically equivalent to expression v1.rearrange(this.toShuffle(), v2). Values held in index vector lanes must lie within valid two vector index range [0, 2*VLEN) else an IndexOutOfBoundException is thrown.
>
> Summary of changes:
> - Java side implementation of new selectFrom API.
> - C2 compiler IR and inline expander changes.
> - In absence of direct two vector permutation instruction in target ISA, a lowering transformation dismantles new IR into constituent IR supported by target platforms.
> - Optimized x86 backend implementation for AVX512 and legacy target.
> - Function tests covering new API.
>
> JMH micro included with this patch shows around 10-15x gain over existing rearrange API :-
> Test System: Intel(R) Xeon(R) Platinum 8480+ [ Sapphire Rapids Server]
>
>
> Benchmark (size) Mode Cnt Score Error Units
> SelectFromBenchmark.rearrangeFromByteVector 1024 thrpt 2 2041.762 ops/ms
> SelectFromBenchmark.rearrangeFromByteVector 2048 thrpt 2 1028.550 ops/ms
> SelectFromBenchmark.rearrangeFromIntVector 1024 thrpt 2 962.605 ops/ms
> SelectFromBenchmark.rearrangeFromIntVector 2048 thrpt 2 479.004 ops/ms
> SelectFromBenchmark.rearrangeFromLongVector 1024 thrpt 2 359.758 ops/ms
> SelectFromBenchmark.rearrangeFromLongVector 2048 thrpt 2 178.192 ops/ms
> SelectFromBenchmark.rearrangeFromShortVector 1024 thrpt 2 1463.459 ops/ms
> SelectFromBenchmark.rearrangeFromShortVector 2048 thrpt 2 727.556 ops/ms
> SelectFromBenchmark.selectFromByteVector 1024 thrpt 2 33254.830 ops/ms
> SelectFromBenchmark.selectFromByteVector 2048 thrpt 2 17313.174 ops/ms
> SelectFromBenchmark.selectFromIntVector 1024 thrpt 2 10756.804 ops/ms
> SelectFromBenchmark.selectFromIntVector 2048 thrpt 2 5398.2...
Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
Pass explicit wrap argument to selectFrom API with default value set to true.
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/20508/files
- new: https://git.openjdk.org/jdk/pull/20508/files/055fb22f..e24632cb
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=20508&range=02
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=20508&range=01-02
Stats: 491 lines in 40 files changed: 430 ins; 1 del; 60 mod
Patch: https://git.openjdk.org/jdk/pull/20508.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/20508/head:pull/20508
PR: https://git.openjdk.org/jdk/pull/20508
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