Re: [PATCH v7 1/4] Create source symlink in perf object dir

[Andi Kleen <ak@linux.intel.com>]

> > On some reflection your changes went into the wrong direction
> > because it ignored the (useful) single group property. Aggregation
> > on time really needs to be in perf report not here.
> 
> Still don't understand this. You are sampling, that's why you use the
> period, how can both samples happen at the same time? Why can't

It's leader sampling ({}:S) , so only one event samples and the others
in the group get collected/reset at the time the sample happens.
So all the events in the group measure the same time interval.

Think of it as a much faster and more efficient (but also more limited)
way to do perf stat -I ..., driven by the leader event.

> something sample twice in the period where 1 thing samples? You assign
> to the counter not accumulate in it, but the whole gnum would be
> broken in that case. Why can't samples be interleaved? What I did was

There's only one sample -- the leader -- each time.

-Andi