Proactive QoS negotiation in asynchronous real-time distributed systems

We present a fast, proactive, quality of service (QoS) negotiation algorithm called BEN, for asynchronous real-time distributed systems. BEN considers an application model where transnode application timeliness and fault-tolerance requirements axe expressed using benefit functions, and anticipated workload and system failure rates during future time intervals are expressed using adaptation functions and reliability functions, respectively. Furthermore, BEN considers an adaptation model where subtasks of application tasks axe replicated at run-time for tolerating failures as well as for sharing workload increases. Given these models, the objective of the algorithm is to maximize the aggregate real-time and fault-tolerance benefit. Since determining the optimal solution is computationally intractable, BEN heuristically computes near-optimal resource allocations in polynomial-time. We show that BEN is faster than another Hill Climbing heuristic algorithm, called HLC, but has close performance to that of HLC.