Re: Intel Memory Ordering White Paper

Nick Piggin
2007-09-08T07:37:16Z

On Saturday 08 September 2007 09:20, Linus Torvalds wrote:
> On Sat, 8 Sep 2007, Nick Piggin wrote:
> > So, can we finally noop smp_rmb and smp_wmb on x86?
>
> Did AMD already release their version? If so, we should probably add a
> commit that does that in somewhat early 2.6.24 rc, and add the pointers to
> the whitepapers in the commit message.

http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/24593.pdf

AMD64 Architecture Programmer's Manual Volume 2: System Programming
section 7.2: Multiprocessor Memory Access Ordering, a paragraph on the
first page says

"Loads do not pass previous loads (loads are not re-ordered). Stores do
not pass previous stores (stores are not re-ordered)"

So, yes, it should be easy to do.