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SubjectRe: [PATCH v5 11/20] x86: perf: Intel PT and LBR/BTS are mutually exclusive
Date
Peter Zijlstra <peterz@infradead.org> writes:

> On Mon, Oct 13, 2014 at 04:45:39PM +0300, Alexander Shishkin wrote:
>> Intel PT cannot be used at the same time as LBR or BTS and will cause a
>> general protection fault if they are used together. In order to avoid
>> fixing up GPs in the fast path, instead we use flags to indicate that
>> that one of these is in use so that the other avoids MSR access altogether.
>>
>
> Yeah, don't like this. Like I've said many times before we should simply
> disallow creating PT events when there are LBR events and vice versa.

Ok, I must have misunderstood you before. This makes things a bit
easier.

Regards,
--
Alex


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