Evaluation of load sharing in HARTS with consideration of its communication activities
Kang Geun Shin, Chao-Ju Hou · IEEE Transactions on Parallel and Distributed Systems · 1996
We rigorously analyze load sharing (LS) in a distributed real-time system, called HARTS (Hexagonal Architecture for Real-Time Systems), while considering LS-related communication activities, such as task transfers and state-change broadcasts. First, we give an overview of the general distributed real-time LS approach described previously, and then adapt it to HARTS by exploiting the topological properties of HARTS. Second, we model task arrival/completion/transfer activities in HARTS as a continuous-time Markov chain from which we derive the distribution of queue length and the rate of generating LS-related traffic-task transfer-out rate and state-region change broadcast rate. Third, we derive the distribution of packet delivery time as a function of LS-related traffic rates by characterizing the hexagonal mesh topology and the virtual cut-through capability of HARTS. Finally, we derive the distribution of task waiting time (the time a task is queued for execution plus the time it would spend if the task is to be transferred), from which the probability of a task failing to complete in time, called the probability of dynamic failure, can be computed. The results obtained from our analytic models are verified through event-driven simulations, and can be used to study the effects of varying various design parameters on the performance of LS while considering the details of LS-related communication activities.