Re: [PATCH -tip] perf_counter/x86: Fix incorrect default branch

From: Ingo Molnar
Date: Wed Jun 10 2009 - 06:44:28 EST



* Yong Wang <yong.y.wang@xxxxxxxxxxxxxxx> wrote:

> On Tue, Jun 09, 2009 at 04:25:06PM +0200, Ingo Molnar wrote:
> >
> > They dont have X86_FEATURE_ARCH_PERFMON set, right?
> >
> > I made the switch statement under the assumption that it covers all
> > existing arch-perfmon CPU models. If not, the 'default:' placement
> > would indeed be buggy.
> >
>
> OK, you are right. X86_FEATURE_ARCH_PERFMON eliminates all the old CPUs.
> However, the logic still seems not correct. Both the Core2 CPUs I'm
> using are recognized as Nehalem/Corei7. /proc/cpuinfo and cpuid outputs
> are given below.
>
> The first one:
> vendor_id : GenuineIntel
> cpu family : 6
> model : 23
> model name : Intel(R) Core(TM)2 Duo CPU P8400 @ 2.26GHz
> stepping : 6
>
> CPUID.0x00000001: eax=0x00010676
>
> The second one:
> vendor_id : GenuineIntel
> cpu family : 6
> model : 15
> model name : Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
> stepping : 6
>
> CPUID.0x00000001: eax=0x000006f6
>
> Looks like it's not enough to just look at boot_cpu_data.x86_model.

Yeah - i've applied the patch you sent, thanks. I'm mostly working
on NHM so i didnt notice.

Ingo
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