> 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 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/01a7dc50..9dd98b8b Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=33113&range=09 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=33113&range=08-09 Stats: 3 lines in 1 file changed: 3 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
