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

From: Yong Wang
Date: Wed Jun 10 2009 - 01:32:09 EST


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.

-Yong
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/