On Mon, 18 Nov 2024 14:38:20 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> @merykitty the object base is always at least `8-byte` aligned, see >> `ObjectAlignmentInBytes` - this also holds for all arrays. But the issue is >> the offset from the object base to the array payload. >> >> @rkennke yes, working on fixing the tests :) > > @eme64 Please correct me if I'm wrong but the issue is you need the base to > be aligned at 32 bytes on AVX2 machines for any alignment for vector > instruction to be meaningful, so I don't see the value of vector alignment at > all. @merykitty > Please correct me if I'm wrong but the issue is you need the base to be > aligned at 32 bytes on AVX2 machines for any alignment for vector instruction > to be meaningful, so I don't see the value of vector alignment at all. First: without `AlignVector`, the vector instructions can have completely free alignment. On x64 and aarch64 generally I think most machines do not need alignment at all. And as far as I know there is also no performance penalty on modern CPUs for misalignment. I could be wrong here. On older CPUs alignment was important for performance though. ------------- PR Comment: https://git.openjdk.org/jdk/pull/20677#issuecomment-2483249163
