Re: [Perfctr-devel] Re: Enabling RDPMC in user space by default

David Gibson
2005-11-29T23:07:24Z

On Tue, Nov 29, 2005 at 11:43:47PM +0100, Andi Kleen wrote:
> > Well, RDPMC isn't defined at all. You're assuming that future processor
> > revisions will have the same or substantially similar PerfCtrs as
> > current processors, and nothing guarantees that at all.
>
> Point, but i guess it is reasonable to assume that future x85 CPUs
> will have cycle counter perfctrs. I cannot imagine anybody dropping
> such a basic facility.

It need not necessarily remain configurable to be in PMC 0 however.
Nor do the the PMC MSRs have to remain fixed..

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!