Re: [PATCH 2/2] perf,core: use parent avg sample period as child initial period

From: Peter Zijlstra
Date: Wed Jan 25 2017 - 10:33:14 EST


On Wed, Jan 18, 2017 at 08:21:02AM -0500, kan.liang@xxxxxxxxx wrote:
> From: Kan Liang <kan.liang@xxxxxxxxx>
>
> perf brings additional overhead when monitoring the task which
> frequently generates child task.
>
> When inheriting a event from parent task to child task, the
> sample_period of original parent event (parent_event->parent) will be
> assigned to child event as its initial period, which is usually the
> default sample_period 1.


Why is that mostly 1? I would expect the parent event's sample_period to
ramp up as well.