dyn_constraint
event->hw.dyn_constraint = ~0ULL;
c = dyn_constraint(cpuc, c, idx);
if (event->hw.dyn_constraint != ~0ULL) {
c2 = dyn_constraint(cpuc, c2, idx);
c2->idxmsk64 &= event->hw.dyn_constraint;
event->hw.dyn_constraint &= hybrid(event->pmu, acr_cntr_mask64);
event->hw.dyn_constraint &= hybrid(event->pmu, acr_cause_mask64);
event->hw.dyn_constraint &= x86_pmu.lbr_counters;
event->hw.dyn_constraint &= pebs_mask;
c = dyn_constraint(cpuc, c, idx);
u64 dyn_constraint;