1. An apparatus, comprising: a graphics processing unit (GPU) comprising: a plurality of storage locations; and a plurality of execution units, wherein: the GPU is configured to implement a plurality of virtual GPUs having corresponding variable priority levels; the GPU is further configured to modify the corresponding variable priority levels of at least one of the plurality of virtual GPUs based on an arbitration scheme; the plurality of execution units are configured to execute GPU commands for the plurality of virtual GPUs; and a priority level for a given GPU command is based on a priority level of a corresponding one of the plurality of virtual GPUs.