1. A method for operating a computer processor comprising a first processor chip having a first processor, and a second processor chip having a second processor, wherein the first and second processor chips are connected in a stacked configuration with the first and second processors connected through vertical connections between the first and second processor chips, the method comprising: generating a first control signal to operate the computer processor in a first mode of operation wherein the first and second processors are configured to implement a run-ahead function, wherein the first processor operates a primary thread of execution and the second processor operates a run-ahead thread of execution; and generating a second control signal to operate the computer processor in a second mode of operation wherein the first and second processors operate independently.