> 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 24994.026 ops/us > ByteShiftBenchmark.ashr256 3 thrpt 2 29289.608 ops/us > ByteShiftBenchmark.ashr512 3 thrpt 2 39944.806 ops/us > ByteShiftBenchmark.autoVecAshr 3 thrpt 2 32592.174 ops/us > ByteShiftBenchmark.autoVecLshl 3 thrpt 2 30668.901 ops/us > ByteShiftBenchmark.lshl128 3 thrpt 2 25247.149 ops/us > ByteShiftBenchmark.lshl256 3 thrpt 2 27345.375 ops/us > ByteShiftBenchmark.lshl512 3 thrpt 2 38500.755 ops/us > ByteShiftBenchmark.lshr128 3 thrpt 2 25081.398 ops/us > ByteShiftBenchmark.lshr256 3 thrpt 2 28272.477 ops/us > ByteShiftBenchmark.lshr512 3 thrpt 2 42186.028 ops/us > > Withopt:- > --------- > Benchmark (shift) Mode Cnt Score Error Units > ByteShiftBenchmark.ashr128 3 thrpt 2 31313.173 ops/us > ByteShiftBenchmark.ashr256 3 thrpt 2 58663.746 ops/us > ByteShiftBenchmark.ashr512 3 thrpt 2 50472.509 ops/us > ByteShiftBenchmark.autoVecAshr 3 thrpt 2 44965.109 ops/us > ByteShiftBenchmark.autoVecLshl 3 thrpt 2 46304.515 ops/us > ByteShiftBenchmark.lshl128 3 thrpt 2 28849.321 ops/us > ByteShiftBenchmark.lshl256 3 thrpt 2 40492.534 ops/us > ByteShiftBenchmark.lshl512 3 thrpt 2 65465.815 ops/us > ByteShiftBenchmark.lshr128 3...
Jatin Bhateja has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new 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/345cb033..2ddc54f5 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=33113&range=07 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=33113&range=06-07 Stats: 54 lines in 4 files changed: 2 ins; 29 del; 23 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
