Comment by charleslmunger
3 hours ago
This is overstated in value; on arm systems with LSE it's faster to use that even for weak operations than to use ll/sc. Even if you are limited to ll/sc the compiler may not put your cas-loop body into the ll/sc region as there's limitations on how many and what type of instructions are permitted there.
Sure, with LSE. But you have to target LSE and get a system that actually contains it, i.e. not the default compiler flags and not the original AWS Graviton.