Re: [PATCH v5 11/20] x86: perf: Intel PT and LBR/BTS are mutually exclusive

[Peter Zijlstra]

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.

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