1. A method for computing credit values for groups of threads, comprising: adding a terminated warp credit amount to a slush-fund value upon terminating a warp; issuing a first instruction for execution by a first group of threads in a streaming multiprocessor during an issue cycle; determining a warp identifier associated with the first group of threads; updating a first warp credit for the first group of threads that is associated with the warp identifier; determining that he slush-fund value indicates that credit is available for addition to a second warp credit; and updating a second warp credit for a second group of threads that is associated with a different warp identifier in response to determining that the slush-fund value indicates that credit is available for addition to the second warp credit, the second group of threads having an eligible instruction ready for execution that was not issued for execution in the streaming multiprocessor during the issue cycle.