Re: [PATCH] Document Linux's memory barriers [try #2]

Paul Mackerras
2006-03-09T01:08:49Z

Linus Torvalds writes:

> > If you ask me, the need for mmiowb on some platforms merely shows that
> > those platforms' implementations of spinlocks and read*/write* are
> > buggy...
>
> You could also state that same as
>
> "If you ask me, the need for mmiowb on some platforms merely shows
> that those platforms perform like a bat out of hell, and I think
> they should be slower"
>
> because the fact is, x86 memory barrier rules are just about optimal for
> performance.

... and x86 mmiowb is a no-op. It's not x86 that I think is buggy.

Paul.