On Wed, Apr 21, 2021 at 03:37:11AM +0900, Namhyung Kim wrote: > On Tue, Apr 20, 2021 at 7:28 PM Peter Zijlstra <pet...@infradead.org> wrote:
> > You forgot NMI. > > Thanks for your explanation. Maybe I'm missing something but > this event is basically for counting and doesn't allow sampling. > Do you say it's affected by other sampling events? Note that > it's not reading from the PMU here, what it reads is a snapshot > of last pmu->read(event) afaik. Even !sampling events will trigger NMI to deal with short hardware counters rolling over. But yes, !sampling can also be updated from NMI by other events if they're in a group etc.. Basically, always assume NMI/PMI can happen.
