Re: hook question

[Dave Dodge <dododge@...>]

On Mon, Oct 16, 2006 at 02:43:45PM -0400, Glenn Maynard wrote:
> FWIW, multiprocessor systems are becoming very common at home, with
> cheap dual-core processors.  I havn't heard of any of them having out-
> of-order accesses, though (being x86-based).

According to comments in the Linux kernel mb/rmb/wmb definitions, some
x86 clones can produce out of order store visibility between CPUs.
x86_64 and newer x86 designs have added memory barrier instructions,
implying that barriers are needed to ensure ordering on SMP systems.
I think there was a lengthy discussion a few months ago on
linux-kernel about barriers and C's "volatile" (having to do with the
implementation of SMP spinlocks).

                                                  -Dave Dodge