Techniques are disclosed relating to thermal control implemented by a power management unit. In some embodiments, the power management unit itself is configured to monitor thermal conditions, implement control for one or more thermal loops, and send reduction alerts, via an inter-chip interconnect, to the processor circuitry it powers. In some embodiments, the power management unit implements both thermal and electromigration control loops. Disclosed techniques may advantageously reduce or avoid thermal issues, potentially with reduced impact on processor performance relative to traditional techniques.