Hi Vince,
On Tue, Oct 1, 2013 at 5:53 AM, Vince Weaver <vincent.wea...@maine.edu> wrote:
> It looks like you're noticing "skid" which means the PC returned by the
> profiling is a little beyond the problem instruction because it is hard
> for the CPU to stop in exactly the right place.
>
> Typically the problem instruction will be a few before, not after. I
> wouldn't think an unconditional branch would have much performance impact.
>
> What CPU do you have? What event are you measuring? If you have a new
> enough system you can look into using the (I think) ":p" flags to try to
> get more precise results, if you aren't already.
I found this table of modifiers:
https://perf.wiki.kernel.org/index.php/Tutorial#Modifiers
But it's not obvious to me if they will improve measurement accuracy.
Cheers,
Johan
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