Re: [PATCH 0/5] Support metric group constraint

From: Liang, Kan
Date: Thu Feb 20 2020 - 14:25:08 EST

On 2/20/2020 11:43 AM, Andi Kleen wrote:
For other metric groups, even they have cycles, the issue should not be
For example, if they have 4 or less events, the cycles can be scheduled to
GP counter instead.
If they have 6 or more events, the weak group will be reject anyway.
Perf tool will open it as non-group (standalone metrics).

Technically it can also happen for 9 events with Hyper Threading off or
on Icelake (8 generic counters)

I didn't think we had any of those, but please double check.

I checked all public metrics groups. Right, we don't have such metrics group with 8 GP events + 1 cycles.
We only need to add watchdog constraint for Page_Walks_Utilization for now.