J. Langou, J. Langou, P. Luszczek, J. Kurzak, A. Buttari, J. Dongarra
{"title":"Exploiting the Performance of 32 bit Floating Point Arithmetic in Obtaining 64 bit Accuracy (Revisiting Iterative Refinement for Linear Systems)","authors":"J. Langou, J. Langou, P. Luszczek, J. Kurzak, A. Buttari, J. Dongarra","doi":"10.1145/1188455.1188573","DOIUrl":"https://doi.org/10.1145/1188455.1188573","url":null,"abstract":"Recent versions of microprocessors exhibit performance characteristics for 32 bit floating point arithmetic (single precision) that is substantially higher than 64 bit floating point arithmetic (double precision). Examples include the Intel's Pentium IV and M processors, AMD's Opteron architectures and the IBM's Cell Broad Engine processor. When working in single precision, floating point operations can be performed up to two times faster on the Pentium and up to ten times faster on the Cell over double precision. The performance enhancements in these architectures are derived by accessing extensions to the basic architecture, such as SSE2 in the case of the Pentium and the vector functions on the IBM Cell. The motivation for this paper is to exploit single precision operations whenever possible and resort to double precision at critical stages while attempting to provide the full double precision results. The results described here are fairly general and can be applied to various problems in linear algebra such as solving large sparse systems, using direct or iterative methods and some eigenvalue problems. There are limitations to the success of this process, such as when the conditioning of the problem exceeds the reciprocal of the accuracy of the single precision computations. In that case the double precision algorithm should be used","PeriodicalId":333909,"journal":{"name":"ACM/IEEE SC 2006 Conference (SC'06)","volume":"08 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128857957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Locality and Parallelism Optimization for Dynamic Programming Algorithm in Bioinformatics","authors":"Guangming Tan, S. Feng, Ninghui Sun","doi":"10.1145/1188455.1188538","DOIUrl":"https://doi.org/10.1145/1188455.1188538","url":null,"abstract":"Dynamic programming has been one of the most efficient approaches to sequence analysis and structure prediction in biology. However, their performance is limited due to the drastic increase in both the number of biological data and variety of the computer architectures. With regard to such predicament, this paper creates excellent algorithms aimed at addressing the challenges of improving memory efficiency and network latency tolerance for nonserial polyadic dynamic programming where the dependences are nonuniform. By relaxing the nonuniform dependences, we proposed a new cache oblivious scheme to enhance its performance on memory hierarchy architectures. Moreover we develop and extend a tiling technique to parallelize this nonserial polyadic dynamic programming using an alternate block-cyclic mapping strategy for balancing the computational and memory load, where an analytical parameterized model is formulated to determine the tile volume size that minimizes the total execution time and an algorithmic transformation is used to schedule the tile to overlap communication with computation to further minimize communication overhead on parallel architectures. The numerical experiments were carried out on several high performance computer systems. The new cache-oblivious dynamic programming algorithm achieve 2-10 speedup and the parallel tiling algorithm with communication-computation overlapping shows a desired potential for fine-grained parallel computing on massively parallel computer systems","PeriodicalId":333909,"journal":{"name":"ACM/IEEE SC 2006 Conference (SC'06)","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127328526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"FFT Program Generation for Shared Memory: SMP and Multicore","authors":"F. Franchetti, Y. Voronenko, Markus Püschel","doi":"10.1145/1188455.1188575","DOIUrl":"https://doi.org/10.1145/1188455.1188575","url":null,"abstract":"The chip maker's response to the approaching end of CPU frequency scaling are multicore systems, which offer the same programming paradigm as traditional shared memory platforms but have different performance characteristics. This situation considerably increases the burden on library developers and strengthens the case for automatic performance tuning frameworks like Spiral, a program generator and optimizer for linear transforms such as the discrete Fourier transform (DFT). We present a shared memory extension of Spiral. The extension within Spiral consists of a rewriting system that manipulates the structure of transform algorithms to achieve load balancing and avoids false sharing, and of a backend to generate multithreaded code. Application to the DFT produces a novel class of algorithms suitable for multicore systems as validated by experimental results: we demonstrate a parallelization speed-up already for sizes that fit into L1 cache and compare favorably to other DFT libraries across all small and midsize DFTs and considered platforms","PeriodicalId":333909,"journal":{"name":"ACM/IEEE SC 2006 Conference (SC'06)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126162325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kurt Stockinger, E. W. Bethel, S. Campbell, E. Dart, K. Wu
{"title":"Detecting Distributed Scans Using High-Performance Query-Driven Visualization","authors":"Kurt Stockinger, E. W. Bethel, S. Campbell, E. Dart, K. Wu","doi":"10.1145/1188455.1188542","DOIUrl":"https://doi.org/10.1145/1188455.1188542","url":null,"abstract":"Modern forensic analytics applications, like network traffic analysis, perform high-performance hypothesis testing, knowledge discovery and data mining on very large datasets. One essential strategy to reduce the time required for these operations is to select only the most relevant data records for a given computation. In this paper, we present a set of parallel algorithms that demonstrate how an efficient selection mechanism - bitmap indexing - significantly speeds up a common analysis task, namely, computing conditional histogram on very large datasets. We present a thorough study of the performance characteristics of the parallel conditional histogram algorithms. As a case study, we compute conditional histograms for detecting distributed scans hidden in a dataset consisting of approximately 2.5 billion network connection records. We show that these conditional histograms can be computed on interactive time scale (i.e., in seconds). We also show how to progressively modify the selection criteria to narrow the analysis and find the sources of the distributed scans","PeriodicalId":333909,"journal":{"name":"ACM/IEEE SC 2006 Conference (SC'06)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129761562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"MPI Performance Analysis Tools on Blue Gene/L","authors":"I. Chung, R. Walkup, H. Wen, Hao Yu","doi":"10.1109/SC.2006.43","DOIUrl":"https://doi.org/10.1109/SC.2006.43","url":null,"abstract":"Applications on today's massively parallel supercomputers are often guided with performance analysis tools toward scalable performance on thousands of processors. However, conventional tools for parallel performance analysis have serious problems due to the large data volume that needs to be handled. In this paper, we discuss the scalability issue for MPI performance analysis on Blue Gene/L, the world's fastest supercomputing platform. First we present an experimental study of existing MPI performance tools that were ported to BG/L from other platforms. These tools can be classified into two categories: profiling tools that collect timing summaries, and tracing tools that collect a sequence of time-stamped events. Profiling tools produce small data volumes and can scale well, but tracing tools tend to scale poorly. We then describe a configurable MPI tracing tool developed for BG/L. By providing a configurable method for trace generation, the volume of trace data can be controlled, and scalability is significantly improved","PeriodicalId":333909,"journal":{"name":"ACM/IEEE SC 2006 Conference (SC'06)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124654410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}