Re: [PATCH 1/5] perf, x86: Don't assume the alternative cycles encoding is architectural

Andi Kleen
2012-06-06T14:12:49Z

On Wed, Jun 06, 2012 at 12:39:48PM +0200, Peter Zijlstra wrote:
> On Tue, 2012-06-05 at 17:56 -0700, Andi Kleen wrote:
> > From: Andi Kleen <ak@linux.intel.com>
> >
> > cycles:p uses an special cycles encoding by default. However that is not
> > architectural, so it can only be used when the CPU is known
> > (it already caused problems on Sandy Bridge). It may or may not work
> > on future CPUs.
> >
> > So make it opt-in only. Right now I enabled it on Core2, Nehalem, Westmere
> > and not on Sandy-Bridge or Atom.
>
> No.

What do you mean? Are you claiming it's architectural?

> Also, c0 is a PEBS capable event on Atom just fine.

Ok can enable it there.

-Andi

--
ak@linux.intel.com -- Speaking for myself only