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

[Alexander Shishkin]

Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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
--
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/