1. A system for managing power comprising: a processor comprising a plurality of processing units, wherein the plurality of processing units comprises a processing unit executing a first thread and a second thread; a thread monitor configured to: determine a first cycles per instruction (CPI) characteristic of the first thread; and determine a second CPI characteristic of the second thread; a component configured to calculate an aggregate CPI metric for the processing unit based on the first CPI characteristic and the second CPI characteristic; and a power manager configured to: modify a clock frequency of the processing unit based on the aggregate CPI metric for the processing unit.