Re: [PATCH 06/14] perf, x86: PEBS infrastructure

Stephane Eranian
2010-03-05T19:51:38Z

On Fri, Mar 5, 2010 at 11:39 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Fri, 2010-03-05 at 11:11 -0800, Stephane Eranian wrote:
>> By rewinding you get the IP of the instruction that caused the event. But the
>> register state is STILL reflecting the situation at retirement of that
>> instruction.
>
> I'm quite aware of that, but its near impossible to reverse interpret
> instructions such as "mov rdx, $rdx", so until we get fault like PEBS
> we'll just have to live with this.
>
I am sure you are, but that's not necessarily true of everybody.
So this needs to be clearly spelled out in some documentation
about precise + your MISC_EXACT bit.