Re: [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL

Andi Kleen
2007-04-02T22:31:49Z

On Monday 02 April 2007 23:56:08 Dave Hansen wrote:
> On Mon, 2007-04-02 at 14:28 -0700, Christoph Lameter wrote:
> > I do not care what its called as long as it
> > covers all the bases and is not a glaring performance regresssion (like
> > SPARSEMEM so far).
>
> I honestly don't doubt that there are regressions, somewhere. Could you
> elaborate, and perhaps actually show us some numbers on this? Perhaps
> instead of adding a completely new model, we can adapt the existing ones
> somehow.

If it works I would be inclined to replaced old sparsemem with Christoph's
new one on x86-64. Perhaps that could cut down the bewildering sparsemem
ifdef jungle that is there currently.

But I presume it won't work on 32bit because of the limited address space?

> But, without some cold, hard, data, we mere mortals without the 1024-way
> machines can only guess. ;)

Yep.

-Andi (who would be scared of a 1024 way x86 machine)