Re: Memory ordering

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