On Wed, Nov 3, 2021 at 11:55 AM Thomas Munro <thomas.mu...@gmail.com> wrote: > 1. Even though we're using generic built-ins for atomics, I guess we > could still use a src/include/port/atomics/arch-riscv.h file so we > have a place to define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY when > building for 64 bit. We'd need to find the chapter-and-verse to > justify that, of course, which I can try to do; if someone more > familiar with the ISA/spec/manual can point to it I'm all ears.
I randomly remembered this topic after seeing an s390x announcement from Christoph[1], and figured he or someone else might be interested in the same observation about that platform. That is, we finally got around to defining this for ARM, but I bet one internet point that RISCV64 and s390x have that property too (but would need to find a written reference, or perhaps a similar declaration in the Linux sources, etc): $ git grep '#define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY' src/include/port/atomics/arch-arm.h:#define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY src/include/port/atomics/arch-ppc.h:#define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY src/include/port/atomics/arch-x86.h:#define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY [1] https://www.postgresql.org/about/news/postgresql-on-s390x-on-debian-and-ubuntu-2752/
