Olaf M. Lubeck

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The POEMS project is creating an environment for endto-end performance modeling of complex parallel and distributed systems, spanning the domains of application software, runtime and operating system software, and hardware architecture. To enable end-to-end modeling of large-scale applications and systems, the POEMS framework is designed to compose models(More)
We develop a model for the parallel performance of algorithms that consist of concurrent, twodimensional wavefronts implemented in a message passing environment. The model, based on a LogGP machine parametrization, combines the separate contributions of computation and communication wavefronts. We validate the model on three important supercomputer systems,(More)
We develop a model for the parallel performance of algorithms that consist of concurrent, twodimensional wavefronts implemented in a message passing environment. The model combines the separate contributions of computation and communication wavefronts. We validate the model on three supercomputer systems, with up to 500 processors, using data from an ASCI(More)
We have recently been studying the performance of wavefront algorithms implemented using message passing on 2dimensional logical processor arrays [1,2]. Wavefront algorithms are ubiquitous in parallel computing, since they represent a means of enabling parallelism in computations that contain recurrences. Our particular interest in wavefront algorithms(More)
In this paper we compare single-processor performance of the SGI Origin and PowerChallenge and utilize a previously-reported performance model for hierarchical memory systems to explain the results. Both the Origin and PowerChallenge use the same microprocessor (MIPS R10000) but have significant differences in their memory subsystems. Our memory model(More)
Although considerable technology has been developed for debugging and developing sequential programs, producing verifiably correct parallel code is a much harder task. In view of the large number of possible scheduling sequences, exhaustive testing is not a feasible method for determining whether a given parallel program is correct; nor have there been(More)
Fully vectorized versions of the Los Alamos National Laboratory benchmark code <italic>Gamteb</italic>, a Monte Carlo photon transport algorithm, were developed for the Cyber 205/ETA-10 and Cray X-MP/Y-MP architectures. Single-processor performance measurements of the vector and scalar implementations were modeled in a modified Amdahl's Law that accounts(More)