On Tue, 14 Nov 2023 08:09:28 GMT, Jatin Bhateja <jbhat...@openjdk.org> wrote:
>> Below is baseline data collected using a modified version of the >> java.lang.foreign.xor micro benchmark referenced by @mcimadamore in the bug >> report. I collected data on an Ubuntu 22.04 laptop with a Tigerlake >> i7-1185G7, which does support AVX512. >> >> Baseline data >> Benchmark (arrayKind) (sizeKind) Mode Cnt Score >> Error Units >> -------------------------------------------------------------------------------------- >> XorTest.copy ELEMENTS SMALL avgt 30 584737355.767 ± >> 60414308.540 ns/op >> XorTest.copy ELEMENTS MEDIUM avgt 30 272248995.683 ± >> 2924954.498 ns/op >> XorTest.copy ELEMENTS LARGE avgt 30 1019200210.900 ± >> 28334453.652 ns/op >> XorTest.copy REGION SMALL avgt 30 7399944.164 ± >> 216821.819 ns/op >> XorTest.copy REGION MEDIUM avgt 30 20591454.558 ± >> 147398.572 ns/op >> XorTest.copy REGION LARGE avgt 30 21649266.051 ± >> 179263.875 ns/op >> XorTest.copy CRITICAL SMALL avgt 30 51079.357 ± >> 542.482 ns/op >> XorTest.copy CRITICAL MEDIUM avgt 30 2496.961 ± >> 11.375 ns/op >> XorTest.copy CRITICAL LARGE avgt 30 515.454 ± >> 5.831 ns/op >> XorTest.copy FOREIGN SMALL avgt 30 7558432.075 ± >> 79489.276 ns/op >> XorTest.copy FOREIGN MEDIUM avgt 30 19730666.341 ± >> 500505.099 ns/op >> XorTest.copy FOREIGN LARGE avgt 30 34616758.085 ± >> 340300.726 ns/op >> XorTest.xor ELEMENTS SMALL avgt 30 219832692.489 ± >> 2329417.319 ns/op >> XorTest.xor ELEMENTS MEDIUM avgt 30 505138197.167 ± >> 3818334.424 ns/op >> XorTest.xor ELEMENTS LARGE avgt 30 1189608474.667 ± >> 5877981.900 ns/op >> XorTest.xor REGION SMALL avgt 30 64093872.804 ± >> 599704.491 ns/op >> XorTest.xor REGION MEDIUM avgt 30 81544576.454 ± >> 1406342.118 ns/op >> XorTest.xor REGION LARGE avgt 30 90091424.883 ± >> 775577.613 ns/op >> XorTest.xor CRITICAL SMALL avgt 30 57231375.744 ± >> 438223.342 ns/op >> XorTest.xor CRITICAL MEDIUM avgt 30 58583884.930 ± >> 375355.215 ns/op >> XorTest.xor CRITICAL LARGE avgt 30 60644832.949 ± >> 588120.738 ns/op >> XorTest.xor FOREIGN SMALL avgt 30 73868679.405 ± >> 819965.524 ns/op >> XorTest.xor FOREIGN MEDIUM avgt 30 88156275.944 ± >> 1051257.152 ns/op >> Xo... > > src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp line 1186: > >> 1184: __ evmovntdquq(Address(dst, index, scale, offset + 0x40), xmm2, >> Assembler::AVX_512bit); >> 1185: __ evmovntdquq(Address(dst, index, scale, offset + 0x80), xmm3, >> Assembler::AVX_512bit); >> 1186: __ evmovntdquq(Address(dst, index, scale, offset + 0xC0), xmm4, >> Assembler::AVX_512bit); > > These are non-temporal memory moves, to force eviction from write combining > buffers we may need to emit additional fences, else a subsequent read from > destination memory may see incorrect values. @jatin-bhateja There is a sfence at line 781. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/16575#discussion_r1393486384
