Horton

Thread

Commits

  1. Declare aarch64 has single copy atomicity for 8 byte values.

  1. AArch64 has single-copy 64 bit atomicity

    Thomas Munro <thomas.munro@gmail.com> — 2021-11-02T22:33:40Z

    Hi,

Andres mentioned in passing that he'd defined
PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY only on Itanium, PPC and x86 but
not ARM.

I took a look at https://developer.arm.com/documentation/ddi0487/gb/
under "B2.2.1 Requirements for single-copy atomicity" and it seemed
like we should turn this on for __aarch64__.  It goes back to the
original ARMv8-A so should cover all 64 bit ARM systems.

  2. Re: AArch64 has single-copy 64 bit atomicity

    Alexander Korotkov <aekorotkov@gmail.com> — 2021-11-03T00:49:29Z

    On Wed, Nov 3, 2021 at 1:34 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> Andres mentioned in passing that he'd defined
> PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY only on Itanium, PPC and x86 but
> not ARM.
>
> I took a look at https://developer.arm.com/documentation/ddi0487/gb/
> under "B2.2.1 Requirements for single-copy atomicity" and it seemed
> like we should turn this on for __aarch64__.  It goes back to the
> original ARMv8-A so should cover all 64 bit ARM systems.

That should be very good because ARM gains popularity and the effect
of atomic read is significant

------
Regards,
Alexander Korotkov