Function plan_sibling_table 

pub fn plan_sibling_table(cpu_to_core: &[(u32, u32)]) -> SiblingPlan

Plan the SMT sibling table from a synthetic (cpu, core) map.

Each CPU’s entry is the lowest-id other CPU sharing its physical core (the core_id from scx_utils::Cpu). A core with a single CPU maps that CPU to itself, the “no sibling” sentinel the BPF side treats as “no preference”. smt_on is set when any entry is a non-self sibling. For >2-way SMT only the lowest-id sibling is reported. This is a preference, not a full pairing, and the input order does not matter (the plan groups by core first).