Re: [REGRESSION] x86, perf: counter freezing breaks rr

Andi Kleen
2018-11-20T22:38:57Z

> In fact, I'll argue FREEZE_ON_OVERFLOW is unfixably broken for
> independent counters, because while one counter overflows, we'll stall
> counting on all others until we've handled the PMI.
>
> Even though the PMI might not be for them and they very much want/need
> to continue counting.

We stop all counters in any case for the PMI. With freeze-on-PMI it just
happens slightly earlier.

-Andi