7227837
Partitionability of k-Extra-Stage Omega Networks and an Optimal Task Migration Algorithm
In a large-scale parallel computing system, partitionability is an important feature that allows a large system to be partitioned into smaller subsystems so that multiple tasks can be run independently on different subsystems. In such a system, a task run on a subsystem may need to be migrated to another subsystem if the subsystem is faulty, if load balance is needed, or if subsystem restructuring is desired. This paper studies the partitionability of k-extra-stage Omega networks and presents an optimal task migration algorithm for k-extra-stage Omega networks.
9442074
Generalized Latin squares II
Abstract This paper is a continuation of a study on a new class of combinatorial structures called generalized Latin squares or 〈k,l〉-Latin squares. Here, we study the existence question of perfect 〈k,l〉-Latin squares. The main result is an existence theorem for the case M = 2, where M is the multiplicity of the generalized Latin squares. Specifically, we show that for given positive integers N, k = ip, l = iq, where i = gcd(k,l), there exists a perfect 〈k,l〉-Latin square of order N with M = 2 if and only if (i) N = 4k, (ii) pq(p + q)| N, and (iii) q|2.
44324303
Equivalent permutation capabilities between time division optical omega network and non-optical extra stage omega network
Since optical networks must support crosstalk-free (CF) connections, regular N/spl times/N multistage interconnection networks (MINs) cannot be directly used to provide connections between N inputs and N outputs. A solution is to use a 2N/spl times/2N Cube-Type MIN to provide the N/spl times/N connections. C. Qiao (1993) proposed a time domain approach that divides the N optical inputs into several groups such that CF connections can be provided by an N/spl times/N regular MIN in several time slots, one for each group. The set of N-permutations realizable in two slots is defined as class /spl theta/. Qiao proved that the size of /spl theta/ is larger than the size of class /spl Omega/, where /spl Omega/ consists of all N-permutations passible through a regular N/spl times/N Omega network. The paper first presents an optimal O(NlgN) time algorithm for identifying whether a given permutation belongs to class /spl theta/ or not. From this algorithm, the paper proves an interesting fact that the class /spl theta/ is identical to the class /spl Omega/+1 which represents the set of N-permutations admissible by a non-optical N/spl times/N one-extra stage Omega network.
37059740
Realization of an Arbitrary Permutation on a Hypercube
We present an explicit combinatorial algorithm for constructing a 2-realization for any given permutation on a circuit-switched d-dimensional hypercube (d-cube) such that the total number of directed edges used in the realization (counting every repetition) is bounded by d2d, the total number of directed edges in the d-cube. As a corollary, this result implies a (2d−3) step realization on a packet-switched d-cube (d⩾3).
34776029
Embedding between 2-D meshes of the same size
It is shown how to embed an x/sub 1/ /spl times/ 1/sub 1/ mesh M/sub 1/ into an s/sub 2/ /spl times/ t/sub 2/ mesh M/sub 2/, where s/sub 1/ /spl times/ t/sub 2/, s/sub 1/ < t/sub i/ (i = 1,2) such that the dilation is minimized. It is assumed that load = 1 and expansion = 1. For each case there is shown a lower bound on the dilation and a corresponding embedding method. The dilations by these embedding algorithms either match a lower bound or are very close to a lower bound.<<ETX>>
33412339
Conservative Algorithms for Parallel and Sequential Integer Sorting
We present a conservative CRCW parallel algorithm for integer sorting. This algorithm sorts n integers from {0, 1, ..., m−1} in time O(n log log min(m,n)/p + log n) using p processors. The simulation of our parallel algorithm on the sequential machine yields a sequential algorithm for integer sorting which sorts n integers from {0, 1, ..., m−1} in time O(n min(log log n, log log m/log n)).
449557
Power allocation and scheduling for MAC layer design in UWB networks
This paper proposes a practical joint power allocation and scheduling scheme for medium access control (MAC) layer design in ultra-wideband (UWB) networks. The scheme increases system spectral efficiency and reduces power consumption by fully considering the properties of the UWB, such as its capacity in supporting parallel transmission and providing accurate positioning, and its stringent constraint on computational complexity. Practical implementations of the proposed scheme are achieved by introducing a margin based power allocation scheme and an exclusive region based scheduling scheme. The margin based power allocation scheme is carried out based on each link's own information, and is simple to implement, while the exclusive region based scheduling scheme takes into account the interaction among different links. Simulation results show that the proposed power allocation and scheduling schemes exhibit good performance in terms of the average number of slots per frame and the power consumption reduction
9685849
Adaptive data partition for sorting using probability distribution
Many computing problems benefit from dynamic partition of data into smaller chunks with better parallelism and locality. However, it is difficult to partition all types of inputs with the same high efficiency. This paper presents a new partition method in sorting scenario based on probability distribution, an idea first studied by Janus and Lamagna in early 1980's on a mainframe computer. The new technique makes three improvements. The first is a rigorous sampling technique that ensures accurate estimate of the probability distribution. The second is an efficient implementation on modern, cache-based machines. The last is the use of probability distribution in parallel sorting. Experiments show 10-30% improvement in partition balance and 20-70% reduction in partition overhead, compared to two commonly used techniques. The new method reduces the parallel sorting time by 33-50% and outperforms the previous fastest sequential sorting technique by up to 30%.
1789234
Phase-Based Miss Rate Prediction Across Program Inputs
Previous work shows the possibility of predicting the cache miss rate (CMR) for all inputs of a program. However, most optimization techniques need to know more than the miss rate of the whole program. Many of them benefit from knowing miss rate of each execution phase of a program for all inputs. 
 
In this paper, we describe a method that divides a program into phases that have a regular locality pattern. Using a regression model, it predicts the reuse signature and then the cache miss rate of each phase for all inputs. We compare the prediction with the actual measurement. The average prediction is over 98% accurate for a set of floating-point programs. The predicted CMR-traces matches the simulated ones in spite of dramatic fluctuations of the miss rate over time. This technique can be used for improving dynamic optimization, benchmarking, and compiler design.
33166016
Indirect RSVP for Virtual Cluster Cellular Mobile IP Networks
Mobile IP (MIP) could be deployed in a wireless cellular network so that the integrated Cellular Mobile IP (CMIP) network can be used to support datagram delivery to mobile users. In order to provide QoS for realtime traffic in IP network, Resource reSerVation Protocol (RSVP) is needed to reserve network resources along the route which the datagrams follow. However, current RSVP fails to operate through the MIP tunnel. Moreover, the high registration rate in a CMIP network greatly degrades RSVP performance. In this paper, an Indirect RSVP (IRSVP) over Virtual Cluster Cellular Mobile IP (VCCMIP) is proposed in which an assistant RSVP connection is introduced to assist the end-to-end major RSVP operation over the MIP tunnel. IRSVP signaling costs and packet loss rates are evaluated. Simulation results show that the proposed scheme can greatly increase RSVP performance in terms of packet loss and RSVP connection active percentage.
16080938
Locality phase prediction
As computer memory hierarchy becomes adaptive, its performance increasingly depends on forecasting the dynamic program locality. This paper presents a method that predicts the locality phases of a program by a combination of locality profiling and run-time prediction. By profiling a training input, it identifies locality phases by sifting through all accesses to all data elements using variable-distance sampling, wavelet filtering, and optimal phase partitioning. It then constructs a phase hierarchy through grammar compression. Finally, it inserts phase markers into the program using binary rewriting. When the instrumented program runs, it uses the first few executions of a phase to predict all its later executions.Compared with existing methods based on program code and execution intervals, locality phase prediction is unique because it uses locality profiles, and it marks phase boundaries in program code. The second half of the paper presents a comprehensive evaluation. It measures the accuracy and the coverage of the new technique and compares it with best known run-time methods. It measures its benefit in adaptive cache resizing and memory remapping. Finally, it compares the automatic analysis with manual phase marking. The results show that locality phase prediction is well suited for identifying large, recurring phases in complex programs.