Ensuring Fair-deal Service in Multi-core Processor Environment

Present day multi-core processors integrate dozens of small processing cores with an on-chip network consisting of point-to-point links. The network enables communication between the processing cores and sharing of common resources such as memory and I/O controllers. In this work, we propose an arbitration scheme to ensure fair-deal service in accessing a chips shared resources by eliminating any bias in accessing a shared resource by a core based on its location in the multi-core chip. We propose using probabilistic arbitration combined with distance-based weights to achieve fair-deal service and overcome the limitation of conventional round-robin arbiter. We describe how nonlinear weights need to be used with probabilistic arbiters and propose three different arbitration weight metrics constant weight, linearly increasing weight, and randomly increasing weight. By simply changing the arbitration of an on-chip router, we can create a simple, low-cost mechanism for achieving fair-deal service without requiring any additional buffers or virtual channels. We evaluate our arbitration scheme across a wide range of traffic patterns. In addition to providing fair-deal service, the proposed arbitration has additional benefits such as providing enhanced throughput, reduced latency, thus, providing a more stable network