Re: [Patch v3 12/22] perf/x86/intel: Update dyn_constranit base on PEBS event precise level

Peter Zijlstra
2025-04-15T13:53:30Z

On Tue, Apr 15, 2025 at 11:44:18AM +0000, Dapeng Mi wrote:
> arch-PEBS provides CPUIDs to enumerate which counters support PEBS
> sampling and precise distribution PEBS sampling. Thus PEBS constraints
> should be dynamically configured base on these counter and precise
> distribution bitmap instead of defining them statically.
>
> Update event dyn_constraint base on PEBS event precise level.

What if any constraints are there on this? CPUID is virt host
controlled, right, so these could be the most horrible masks ever.

This can land us in EVENT_CONSTRAINT_OVERLAP territory, no?