On Thu, 23 May 2024 17:25:34 GMT, Scott Gibbons <sgibb...@openjdk.org> wrote:
>> Re-write the IndexOf code without the use of the pcmpestri instruction, only >> using AVX2 instructions. This change accelerates String.IndexOf on average >> 1.3x for AVX2. The benchmark numbers: >> >> >> Benchmark Score >> Latest >> StringIndexOf.advancedWithMediumSub 343.573 317.934 >> 0.925375393x >> StringIndexOf.advancedWithShortSub1 1039.081 1053.96 >> 1.014319384x >> StringIndexOf.advancedWithShortSub2 55.828 110.541 >> 1.980027943x >> StringIndexOf.constantPattern 9.361 11.906 >> 1.271872663x >> StringIndexOf.searchCharLongSuccess 4.216 4.218 >> 1.000474383x >> StringIndexOf.searchCharMediumSuccess 3.133 3.216 >> 1.02649218x >> StringIndexOf.searchCharShortSuccess 3.76 3.761 >> 1.000265957x >> StringIndexOf.success 9.186 >> 9.713 1.057369911x >> StringIndexOf.successBig 14.341 46.343 >> 3.231504079x >> StringIndexOfChar.latin1_AVX2_String 6220.918 12154.52 >> 1.953814533x >> StringIndexOfChar.latin1_AVX2_char 5503.556 5540.044 >> 1.006629895x >> StringIndexOfChar.latin1_SSE4_String 6978.854 6818.689 >> 0.977049957x >> StringIndexOfChar.latin1_SSE4_char 5657.499 5474.624 >> 0.967675646x >> StringIndexOfChar.latin1_Short_String 7132.541 >> 6863.359 0.962260014x >> StringIndexOfChar.latin1_Short_char 16013.389 16162.437 >> 1.009307711x >> StringIndexOfChar.latin1_mixed_String 7386.123 14771.622 >> 1.999915517x >> StringIndexOfChar.latin1_mixed_char 9901.671 9782.245 >> 0.987938803 > > Scott Gibbons has updated the pull request incrementally with one additional > commit since the last revision: > > Fix for IndexOf.java on mac src/hotspot/cpu/x86/stubGenerator_x86_64_string.cpp line 268: > 266: __ cmpq(needle_len_p, 0); > 267: __ jg_b(L_nextCheck); > 268: __ xorq(rax, rax); out of curiosity, is there any advantage to using `xorq` instead of `xorl` here? https://stackoverflow.com/a/33668295/7707617 suggests that `xorl` might be better, but it's a bit dated now. src/hotspot/cpu/x86/stubGenerator_x86_64_string.cpp line 449: > 447: __ cmpq(r13, NUMBER_OF_CASES - 1); > 448: __ ja(L_smallCaseDefault); > 449: __ mov64(r15, (int64_t)small_jump_table); would it make sense to use `lea` here? src/hotspot/cpu/x86/stubGenerator_x86_64_string.cpp line 803: > 801: __ movq(index, needle_len); > 802: __ andq(index, 0xf); // nLen % 16 > 803: __ movq(offset, 0x10); `movl` or `movptr` would produce a shorter encoding src/hotspot/cpu/x86/stubGenerator_x86_64_string.cpp line 1544: > 1542: } > 1543: > 1544: __ align(8); why `8` and not `OptoLoopAlignment` ? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/16753#discussion_r1612178285 PR Review Comment: https://git.openjdk.org/jdk/pull/16753#discussion_r1612179069 PR Review Comment: https://git.openjdk.org/jdk/pull/16753#discussion_r1612180163 PR Review Comment: https://git.openjdk.org/jdk/pull/16753#discussion_r1612183311
