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From: jseigh <jseigh_es00@xemaps.com>
Newsgroups: comp.arch
Subject: Re: Memory ordering
Date: Sun, 17 Nov 2024 09:03:06 -0500
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On 11/16/24 16:21, Chris M. Thomasson wrote:

> Fwiw, in C++ std::memory_order_consume is useful for traversing a node 
> based stack of something in RCU. In most systems it only acts like a 
> compiler barrier. On the Alpha, it must emit a membar instruction. Iirc, 
> mb for alpha? Cannot remember that one right now.

That got deprecated.  Too hard for compilers to deal with.  It's now
same as memory_order_acquire.

Which brings up an interesting point.  Even if the hardware memory
memory model is strongly ordered, compilers can reorder stuff,
so you still have to program as if a weak memory model was in
effect.   Or maybe disable reordering or optimization altogether
for those target architectures.

Joe Seigh