Analysing Real-Time Traffic in Wormhole-Switched On-ChipNetworks

• Main Authors: Wu, Taodi, Ding, Shuyang
• Format: Others
• Language: English
• Published: Mälardalens högskola, Inbyggda system 2016
• Subjects: network-on-chip; wormhole switching; fixed-priority; round robin; schedula-bility analysis; Computer Sciences; Datavetenskap (datalogi)
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-32057

With the increasing demand of computation capabilities, many-core processors are gain-ing more and more attention. As a communication subsystem many-core processors, Network-on-Chip (NoC) draws a lot of attention in the related research fields. A NoC is used to deliver messages among different cores. For many applications, timeliness is of great importance, especially when the application has hard real-time requirements. Thus, the worst-case end-to-end delays of all the messages passing through a NoC should be concerned. Unfortunately, there is no existing analysis tool that can support multiple NoC architectures as well as provide a user-friendly interface.This thesis focuses on a wormhole switched NoC using different arbitration policies which are Fixed Priority (FP) and Round Robin (RR) respectively. FP based arbitration policy includes distinct and shared priority based arbitration policies. We have developed a timing analysis tool targeting the above NoC designs. The Graphical User Interface (GUI) in the tool can simplify the operation of users. The tool takes characteristics of flow sets as input, and returns results regarding the worst-case end-to-end delay of each flow. These results can be used to assist the design of real-time applications on the corre-sponding platform.A number of experiments have been generated to compare different arbitration mecha-nisms using the developed tool. The evaluation focuses on the effect of different param-eters including the number of flows and the number of virtual-channels in a NoC, and the number of hops of each flow. In the first set of experiment, we focus on the schedulabil-ity ratio achieved by different arbitration policies regarding the number of flows. The sec-ond set of experiments focus on the comparison between NoCs with different number of virtual-channels. In the last set of experiments, we compare different arbitration mecha-nisms with respect to the worst-case end-to-end latencies.