Messages in this thread | | | Date | Wed, 02 Jul 2014 10:07:14 +0900 (JST) | Subject | Re: [PATCH v2] perf/x86/intel: ignore CondChgd bit to avoid false NMI handling | From | HATAYAMA Daisuke <> |
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From: Andi Kleen <ak@linux.intel.com> Subject: Re: [PATCH v2] perf/x86/intel: ignore CondChgd bit to avoid false NMI handling Date: Mon, 30 Jun 2014 15:22:24 -0700
>> >> I'm also interested in the behaviour of CondChgd bit on Ivy Bridge processors. > > The intended meaning of CondChgd is that a hardware debugger has taken over the > PMU. It shouldn't really be set in other circumstances. >
Thanks for your explanation.
The hardware debugger you mean is a kind of ITP?
> I think right now for perf it would be best to just ignore it. > > In theory could stop using the PMU, but if some BIOS set it it would > completely disable perf there. So better to just ignore it. >
I'll reflect this information in the patch description.
-- Thanks. HATAYAMA, Daisuke
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