> Hi All, > > x86 AVX-512 targets provides packed shifts for 16, 32, and 64-bit lanes, but > not for bytes. C2 lowers LShiftVB, RShiftVB, and URShiftVB by widening bytes > to words, shifting, masking, and packing. That sequence is the byte-shift > bottleneck. > > GFNI **gf2p8affineqb** instruction applies one 8×8 bit matrix to every byte. > Logical left, logical right, and arithmetic right shifts by 0..7 are fixed > matrices derived from the identity 0x0102040810204080. > > Patch uses this lowering for 128-, 256-, and 512-bit vectors when GFNI is > available and keeps the existing widen/shift/pack path when GFNI is absent. > > Following are the performance numbers of benchmark included with the patch. > > System: AMD EPYC 9755 128-Core Processor (Turin) Fixed frequency 2.5Ghz > > Baseline:- > ---------- > Benchmark (shift) Mode Cnt Score Error Units > ByteShiftBenchmark.ashr128 3 thrpt 2 24787.795 ops/us > ByteShiftBenchmark.ashr256 3 thrpt 2 29184.019 ops/us > ByteShiftBenchmark.ashr512 3 thrpt 2 42397.653 ops/us > ByteShiftBenchmark.lshl128 3 thrpt 2 25241.434 ops/us > ByteShiftBenchmark.lshl256 3 thrpt 2 28274.012 ops/us > ByteShiftBenchmark.lshl512 3 thrpt 2 47331.675 ops/us > ByteShiftBenchmark.lshr128 3 thrpt 2 25197.166 ops/us > ByteShiftBenchmark.lshr256 3 thrpt 2 27587.841 ops/us > ByteShiftBenchmark.lshr512 3 thrpt 2 38011.674 ops/us > > Withopt:- > --------- > Benchmark (shift) Mode Cnt Score Error Units > ByteShiftBenchmark.ashr128 3 thrpt 2 30674.163 ops/us > ByteShiftBenchmark.ashr256 3 thrpt 2 43275.297 ops/us > ByteShiftBenchmark.ashr512 3 thrpt 2 72744.344 ops/us > ByteShiftBenchmark.lshl128 3 thrpt 2 28799.612 ops/us > ByteShiftBenchmark.lshl256 3 thrpt 2 40797.362 ops/us > ByteShiftBenchmark.lshl512 3 thrpt 2 82156.329 ops/us > ByteShiftBenchmark.lshr128 3 thrpt 2 30325.171 ops/us > ByteShiftBenchmark.lshr256 3 thrpt 2 42775.756 ops/us > ByteShiftBenchmark.lshr512 3 thrpt 2 65255.800 ops/us > > > > Kindly review and share your feedback. > > Best Regards, > Jatin > > --------- > - [x] I confirm that I make this contribution in accordance with the [OpenJDK > Interim AI Policy](https://openjdk.org/legal/a...
Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision: Review comments resolution ------------- Changes: - all: https://git.openjdk.org/jdk/pull/33113/files - new: https://git.openjdk.org/jdk/pull/33113/files/b4d4996a..67b4424e Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=33113&range=02 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=33113&range=01-02 Stats: 45 lines in 1 file changed: 45 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/33113.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/33113/head:pull/33113 PR: https://git.openjdk.org/jdk/pull/33113
