Workload Factoring with the Cloud: A Game-Theoretic Perspective

Cloud computing is an emerging paradigm in which tasks are assigned to a combination ("cloud") of servers and devices, accessed over a network. Typically, the cloud constitutes an additional means of computation and a user can perform workload factoring, i.e., split its load between the cloud and its other resources. Based on empirical data, we demonstrate that there is an intrinsic relation between the "benefit" that a user perceives from the cloud and the usage pattern followed by other users. This gives rise to a non-cooperative game, which we model and investigate. We show that the considered game admits a Nash equilibrium. Moreover, we show that this equilibrium is unique. We investigate the "price of anarchy" of the game and show that, while in some cases of interest the Nash equilibrium coincides with a social optimum, in other cases the gap can be arbitrarily large. We show that, somewhat counter-intuitively, exercising admission control to the cloud may deteriorate its performance. Furthermore, we demonstrate that certain (heavy) users may "scare off" other, potentially large, communities of users. Accordingly, we propose a resource allocation scheme that addresses this problem and opens the cloud to a wide range of user types.