A distributed Key Message algorithm to optimize the communication in clusters

The Key Message (KM) approach prioritizes communications along the critical path to speed up the execution of parallel applications in a cluster environment. However, the current KM approaches (i.e, the Static KM (SKM) and the dynamic KM with a central predictor (CDKM)) either lack the capability of adapting to dynamic environment or suffer from the expensive centralized control to predict dynamic critical path rendering them to be suboptimal.In this paper, we introduce a dynamic and distributed KM algorithm (DDKM) that takes this dynamic nature into account while avoiding overheads of central control, thus, overcoming the drawbacks of its predecessors. To evaluate the DDKM algorithm, we implement it and simulate it in a cluster environment whose communication network (e.g., shared bus) can be modeled as an M/D/1. We compare DDKM with current KM approaches. The performance of DDKM is close to that of CDKM, and much better than SKM up to 28.9% when the network is highly congested. These results demonstrate that DDKM is a promising optimization in a real cluster environment.