Browsing by Author "Abali, B."

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Open Access
Adaptive routing on the new switch chip for IBM SP systems
(Academic Press, 2001) Abali, B.; Stunkel, C. B.; Herring, J.; Banikazemi, M.; Panda, D. K.; Aykanat, Cevdet; Aydogan, Y.
The IBM RS/6000 SP is one of the most successful commercially available multicomputers. SP owes its success partially to the scalable, high bandwidth, low latency network. This paper describes the architecture of Switch2 switch chip, the recently developed third generation switching element which future IBM RS/6000 SP systems may be based on. Switch2 offers significant enhancements over the existing SP switch chips by incorporating advances in both VLSI technology and interconnection network research. One of the major new features of Switch2 is the incorporation of adaptive routing support into it. We describe the adaptive source routing architecture of the Switch2 chip which is a unique feature of this chip. The performance of the adaptive source routing and oblivious routing for a wide range of system characteristics and traffic patterns is evaluated. It is shown that adaptive source routing outperforms or performs comparably with oblivious routing. We propose two novel algorithms for generating adaptive routes specifications required for enabling the usage of adaptive source routing. A comparison between the cost of these two algorithms and the performance improvement obtained from using these algorithms are discussed. We also propose different output selection functions to be used in switching elements for implementing the adaptive routing. We evaluate and compare the performance of these selection functions and discover that the best selection functions for BMINs are not dependent on the traffic pattern, message size, or system size. © 2001 Academic Press.
Open Access
Adaptive source routing in multistage interconnection networks
(IEEE, 1996-04) Aydoğan, Yücel; Stunkel, C. B.; Aykanat, Cevdet; Abali, B.
We describe the adaptive source routing (ASR) method which is a first attempt to combine adaptive routing and source routing methods. In ASR, the adaptivity of each packet is determined at the source processor. Every packet can be routed in a fully adaptive or partially adaptive or non-adaptive manner, all within the same network at the same time. We evaluate and compare performance of the proposed adaptive source routing networks and oblivious routing networks by simulations. We also describe a route generation algorithm that determines maximally adaptive routes in multistage networks.
Open Access
Balanced parallel sort on hypercube multiprocessors
(IEEE, 1993) Abali, B.; Özgüner, F.; Bataineh, A.
A parallel sorting algorithm for sorting n elements evenly distributed over Zd = p nodes of a d-dimensional hypercube is presented. The average running time of the algorithm is O( (n log n)/p + p log2 n). The algorithm maintains a perfect load balance in the nodes by determining the (kn/p)th elements (k = 1,. . . , (p - 1)) of the final sorted list in advance. These p - 1 keys are used to partition the sorted sublists in each node to redistribute data to the nodes to be merged in parallel. The nodes finish the sort with an equal number of elements (n/p) regardless of the data distribution. A parallel selection algorithm for determining the balanced partition keys in O(p log2 n) time is presented. The speed of the sorting algorithm is further enhanced by the distanced communication capability of the iPSC/2 hypercube computer and a novel conflict-free routing algorithm. Experimental results on a 16-node hypercube computer show that the new sorting algorithm is competitive with the previous algorithms, and faster for skewed data distributions.