An Adaptive Unicast/Multicast Routing Algorithm for MPSoCs
ABSTRACT Several parallel applications in MPSoCs take advantage of multicast communication. Path-based multicast scheme has been proven to be more efficient than the others multicast schemes in on-chip interconnection network. We present a new adaptive path based model for both the multicast and unicast wormhole routing protocols. The proposed model under mixed traffic models has lower latency than the previous path-based methods with negligible hardware overhead.
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ABSTRACT: We show that deadlocks due to dependencies on consumption channels are a fundamental problem in wormhole multicast routing. This type of resource deadlocks has not been addressed in many previously proposed wormhole multicast algorithms. We also show that deadlocks on consumption channels can be avoided by using multiple classes of consumption channels and restricting the use of consumption channels by multicast messages. We provide upper bounds for the number of consumption channels required to avoid deadlocks. In addition, we present a new multicast routing algorithm, column-path, which is based on the well-known dimension-order routing used in many multicomputers and multiprocessors. Therefore, this algorithm could be implemented in existing multicomputers with simple changes to the hardware. Using simulations, we compare the performance of the proposed column-path algorithm with the previously proposed Hamiltonian-path-based multipath and an e-cube-based multicast routing algorithms. Our results show that for multicast traffic, the column-path routing offers higher throughputs, while the multipath algorithm offers lower message latencies. Another result of our study is that the commonly implemented simplistic scheme of sending one copy of a multicast message to each of its destinations exhibits good performance provided the number of destinations is smallIEEE Transactions on Parallel and Distributed Systems 07/1998; · 1.80 Impact Factor
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ABSTRACT: This paper presents a model for designing adaptive wormhole routing algorithms for meshes without virtual channels. The model restricts the locations where some turns can be taken so that deadlock is avoided. In comparison with previous methods, the degree of routing adaptiveness provided by the model is more even for different source-destination pairs. The mesh network may benefit from this feature in terms of communication efficiency. Simulation results show that the even adaptiveness provided by the odd-even turn model makes message routing less vulnerable to nonuniform factors such as hot spot traffic. In addition, this property results in a smaller fluctuation of the network performance with respect to different traffic patternsIEEE Transactions on Parallel and Distributed Systems 08/2000; · 1.80 Impact Factor
Article: The Turn Model for Adaptive Routing[show abstract] [hide abstract]
ABSTRACT: We present a model for designing wormhole routing algorithms that are deadlock free, livelock free, minimal or nonminimal, and maximally adaptive. A unique feature of this model is that it is not based on adding physical or virtual channels to network topologies (though it can be applied to networks with extra channels). Instead, the model is based on analyzing the directions in which packets can turn in a network and the cycles that the turns can form. Prohibiting just enough turns to break all of the cycles produces routing algorithms that are deadlock free, livelock free, minimal or nonminimal, and maximally adaptive for the network. In this paper, we focus on the two most common network topologies for wormhole routing, n-dimensional meshes and k-ary n-cubes, without extra channels. In an n-dimensional mesh, just a quarter of the turns must be prohibited to prevent deadlock. The remaining three quarters of the turns permit partial adaptiveness in routing. Partially adaptive routing ...09/1999;