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Sender: Andrew Haley <aph@zarquon.pink>
From: aph@littlepinkcloud.invalid
Subject: Re: Memory ordering
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jseigh <jseigh_es00@xemaps.com> wrote:
> 
> C++ doesn't use #LoadStore, etc... memory ordering terminology.  They
> use acquire, release, cst, relaxed, ...  While in some cases it's
> straightforward as to what that means, in others it's less obvious.

Indeed you don't know the exact mapping to instructions, but that's
the idea: you ask for the ordering model you want, and the compiler
chooses the instructions.

> Non-obvious isn't exactly what you want when writing multi-threaded
> code.  There's enough subtlety as it is.

There are efficiency advantages to be had from getting away from
explicit barriers, though. AArch64 has seq-cst load and store
instructions which don't need the sledgehammer of of a full StoreLoad
between a store and a load.

Andrew.