Communication System, Based On Message Passing Between The Fleet Of Machines

Parallel processing is one of the hottest topics of the computer science today. And of all kinds of parallel computers two ones are becoming the mainstream which take advantages of the message-passing technique. These two kinds of parallel computers are massively parallel processors(MPP) and clusters. This thesis gives a model to evaluate the performance of the inter-node communication subsystem of cluster and tells the details of its implementation.With the fast development of micro-processors the performance of parallel computers are becoming more and more dependent on the functions and efficiency of their communication subsystems. On the one way the acceleration of communication subsystems can reduce the overhead and latency so as to make applications run faster, on the other hand overlapping of computation and communication can hide the communication latency so applications can see little of it.This thesis analyses all the data links of cluster and classifies them as two types of channels: buffered single-link and wormhole Mesh. The models to evaluate their performance are given and then equations listed which tell the relations of bandwidth, latency, flow rate and buffer sizes.Following these models we can see: when the rate of data flow is low or the load of Mesh is light the latency of such a communication subsystem seems approximately irrelevant to the communication distance; when the flow rate rises or the load of Mesh becomes heavier the latency rises much more rapidly. And with the stable data flow the bandwidth of communication subsystem keeps identical with the minimum one of all sublinks. When the flow fluctuate or the Mesh becomes blocked data buffers will work to sustain the bandwidth. At the same time if the noise of channels is considered the buffers which divide a long link into some shorter ones may make errors fewer.The implementation of PMI which is one of the key devices of inter-node communication subsystem of cluster is the basis to...