Current state-of-the-art in GPU networking advocates a hostcentric model that reduces performance and increases code complexity. Recently, researchers have explored several techniques for networking within a GPU kernel itself. These approaches, however, sufer from high latency, waste energy on the host, and are not scalable with larger/more GPUs on a node. In this work, we introduce Command Processor Networking (ComP-Net), which leverages the availability of scalar cores integrated on the GPU itself to provide highperformance intra-kernel networking. ComP-Net enables eicient synchronization between the Command Processors and Compute Units on the GPU through a line locking scheme implemented in the GPU's shared last-level cache. We illustrate that ComP-Net can improve application performance by up to 20% and provide up to 50% reduction in energy consumption vs. competing networking techniques across a Jacobi stencil, allreduce collective, and machine learning applications. CCS CONCEPTS • Computer systems organization → Heterogeneous (hybrid) systems;