Re: Uses for memory barriers

[Segher Boessenkool]

> This can't be right.  Together 1 and 2 would obviate the need for  
> wmb().
> The CPU doing "STORE A; STORE B" will always see the operations  
> occuring
> in program order by 1, and hence every other CPU would always see them
> occurring in the same order by 2 -- even without wmb().
>
> Either 2 is too strong, or else what you mean by "perceived" isn't
> sufficiently clear.

2. is only for multiple stores to a _single_ memory location -- you
use wmb() to order stores to _separate_ memory locations.


Segher

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