On Mon, 8 Apr 2024 19:11:19 GMT, Scott Gibbons <sgibb...@openjdk.org> wrote:
>> This code makes an intrinsic stub for `Unsafe::setMemory` for x86_64. See >> [this PR](https://github.com/openjdk/jdk/pull/16760) for discussion around >> this change. >> >> Overall, making this an intrinsic improves overall performance of >> `Unsafe::setMemory` by up to 4x for all buffer sizes. >> >> Tested with tier-1 (and full CI). I've added a table of the before and >> after numbers for the JMH I ran (`MemorySegmentZeroUnsafe`). >> >> [setMemoryBM.txt](https://github.com/openjdk/jdk/files/14808974/setMemoryBM.txt) > > Scott Gibbons has updated the pull request incrementally with one additional > commit since the last revision: > > Add movq to locate_operand src/hotspot/cpu/x86/macroAssembler_x86.cpp line 5988: > 5986: movw(Address(to, 0), value); > 5987: addptr(to, 2); > 5988: subptr(count, 1<<(shift-1)); At line 5968 also we need the change from cmpl to cmpptr. cmpl(count, 2<<shift); // Short arrays (< 8 bytes) fill by element src/hotspot/cpu/x86/macroAssembler_x86.cpp line 6050: > 6048: vpbroadcastd(xtmp, xtmp, Assembler::AVX_512bit); > 6049: > 6050: subptr(count, 16 << shift); At line 6045 also the cmpl should change to cmpptr: cmpl(count, VM_Version::avx3_threshold()); ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18555#discussion_r1560205702 PR Review Comment: https://git.openjdk.org/jdk/pull/18555#discussion_r1560213265
