1. A computer system operatively coupled to a number of client computer devices, the computer system comprising: a memory that holds an operating system (OS) having a kernel, the operating system configured to launch a plurality of computing processes that are performed in response to requests from the client computer devices; and a plurality of graphics processing units (GPUs) coupled to the memory, each of the GPUs configured to execute instructions on behalf of the computing processes subject to a GPU service request; the kernel comprising: a front-end driver module instantiated in the kernel and configured to receive a GPU service request from any of the computing processes; and multiple back-end driver modules instantiated in the kernel, each of the back-end driver modules associated with a respective subset of the GPUs, wherein the front-end driver module is configured to send the GPU service request to any of the back-end driver modules, wherein the front-end driver module is further configured to determine which back-end driver module of the back-end driver modules is to receive the GPU service request from the front-end driver module, and wherein the back-end driver module that receives the GPU service request is configured to pass the GPU service request to a GPU associated with the back-end driver module.