Re: Improving spin-lock implementation on ARM.

On Thu, Nov 26, 2020 at 7:35 AM Krunal Bauskar <krunalbauskar(at)gmail(dot)com> wrote:
> * x86 uses optimized xchg operation.
> ARM too started supporting it (using Large System Extension) with
> ARM-v8.1 but since it not supported with ARM-v8, GCC default tends
> to roll more generic load-store assembly code.
>
> * gcc-9.4+ onwards there is support for outline-atomics that could emit
> both the variants of the code (load-store and cas/swp) and based on
> underlying supported architecture proper variant it used but still a lot
> of distros don't support GCC-9.4 as the default compiler.

I've checked that gcc 9.3 with "-march=armv8-a+lse" option uses LSE atomics...

------
Regards,
Alexander Korotkov