We present our work on hardware accelerated genomics pipelines, using either FPGAs or GPUs to accelerate execution of BWA-MEM, a widely-used algorithm for genomic short read mapping. The mapping stage can take up to 40% of overall processing time for genomics pipelines. Our implementation offloads the Seed Extension function, one of the main BWA-MEM computational functions, onto an accelerator. Sequencers typically output reads with a length of 150 base pairs. However, read length is expected to increase in the near future. Here, we investigate the influence of read length on BWA-MEM performance using data sets with read length up to 400 base pairs, and introduce methods to ameliorate the impact of longer read length. For the industry-standard 150 base pair read length, our implementation achieves an up to two-fold increase in overall application-level performance for systems with at most twenty-two logical CPU cores. Longer read length requires commensurately bigger data structures, which directly impacts accelerator efficiency. The two-fold performance increase is sustained for read length of at most 250 base pairs. To improve performance, we perform a classification of the inefficiency of the underlying systolic array architecture. By eliminating idle regions as much as possible, efficiency is improved by up to +95%. Moreover, adaptive load balancing intelligently distributes work between host and accelerator to ensure use of an accelerator always results in performance improvement, which in GPU-constrained scenarios provides up to +45% more performance.
Abstract-We present the first accelerated implementation of BWA-MEM, a popular genome sequence alignment algorithm widely used in next generation sequencing genomics pipelines. The Smith-Waterman-like sequence alignment kernel requires a significant portion of overall execution time. We propose and evaluate a number of FPGA-based systolic array architectures, presenting optimizations generally applicable to variable length Smith-Waterman execution. Our kernel implementation is up to 3x faster, compared to software-only execution. This translates into an overall application speedup of up to 45%, which is 96% of the theoretically maximum achievable speedup when accelerating only this kernel.
This poster explores navigation, interaction and stereoscopic display in a multi-scale virtual space. When interaction, especially two-handed, direct manipulation, is combined with stereoscopic stationary displays, there are trade-offs that must be considered. This poster gives an overview of these design issues and briefly describes our current multi-scale, application for exploring volumetric weather in its geospatial context in a VR system. The general importance of recognizing and using defined areas of user focus and of semi-automatically bringing these areas into the optimal interaction volume of the display system is described.
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