2003-11-18 13:48:44

by Andi Kleen

[permalink] [raw]
Subject: Re: FEATURE REQUEST: Specific Processor Optimizations on x86 Architecture

Zwane Mwaikambo <[email protected]> writes:

> On Mon, 27 Oct 2003, Andi Kleen wrote:
>
> > The wmb() change is not needed, unless you have an oostore CPU
> > (x86 has ordered writes by default). It probably does not hurt
> > neither though (I do it the same way on x86-64), but also doesn't
> > change anything.
>
> The original intent was to fix an SMP P5 system, it oopses otherwise under
> load.

That doesn't make any sense. P5 doesn't support SFENCE.

-Andi


2003-11-18 14:29:07

by Zwane Mwaikambo

[permalink] [raw]
Subject: Re: FEATURE REQUEST: Specific Processor Optimizations on x86 Architecture

On Mon, 27 Oct 2003, Andi Kleen wrote:

> Zwane Mwaikambo <[email protected]> writes:
>
> > On Mon, 27 Oct 2003, Andi Kleen wrote:
> >
> > > The wmb() change is not needed, unless you have an oostore CPU
> > > (x86 has ordered writes by default). It probably does not hurt
> > > neither though (I do it the same way on x86-64), but also doesn't
> > > change anything.
> >
> > The original intent was to fix an SMP P5 system, it oopses otherwise under
> > load.
>
> That doesn't make any sense. P5 doesn't support SFENCE.

I think i misparsed what you were referring to, i thought it was the patch
with the barrier in smp_call_function().

My bad.