[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-kernel
Subject:    Re: [PATCH v2] perf/x86/intel: ignore CondChgd bit to avoid false NMI handling
From:       Andi Kleen <ak () linux ! intel ! com>
Date:       2014-06-30 22:22:24
Message-ID: 20140630222224.GH19781 () tassilo ! jf ! intel ! com
[Download RAW message or body]

> 
> 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.

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.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
[prev in list] [next in list] [prev in thread] [next in thread]