FPGAs are quickly becoming available in the cloud as a one more heterogeneous processing element complementing CPUs and GPUs. There are many reports in the literature showing the potential for FPGAs to accelerate a wide variety of algorithms, which combined with their growing availability, would seem to also indicate a widespread use in many applications. Unfortunately, there is not much published research exploring what it takes to integrate an FPGA into an existing application in a cost-effective way and keeping the algorithmic performance advantages. Building on recent results exploring how to employ FPGAs to improve the search engines used in the travel industry, this paper analyses the end-to-end performance of the search engine when using FPGAs, as well as the necessary changes to the software and the cost of such deployments. The results provide important insights on current FPGA deployments and what needs to be done to make FPGAs more widely used. For instance, the large potential performance gains provided by an FPGA are greatly diminished in practice if the application cannot submit request in the most optimal way, something that is not always possible and might require significant changes to the application. Similarly, some existing cloud deployments turn out to use a very imbalanced architecture: a powerful FPGA connected to a not so powerful CPU. The result is that the CPU cannot generate enough load for the FPGA, which potentially eliminates all performance gains and might even result in a more expensive system. In this paper, we report on an extensive study and development effort to incorporate FPGAs into a search engine and analyse the issues encountered and their practical impact. We expect that these results will inform the development and deployment of FPGAs in the future by providing important insights on the end-to-end integration of FPGAs within existing systems.

中文翻译：

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从研究到概念验证：分析 FPGA 在商业搜索引擎上的部署

FPGA 作为补充 CPU 和 GPU 的另一种异构处理元件，正迅速在云中可用。文献中有许多报告显示 FPGA 具有加速各种算法的潜力，再加上其日益增长的可用性，似乎也表明 FPGA 在许多应用中的广泛使用。不幸的是，没有多少已发表的研究探讨如何以经济高效的方式将 FPGA 集成到现有应用程序中并保持算法性能优势。基于最近探索如何使用 FPGA 来改进旅游行业使用的搜索引擎的结果，本文分析了使用 FPGA 时搜索引擎的端到端性能，以及对软件的必要更改和成本此类部署。结果提供了关于当前 FPGA 部署以及需要做什么才能使 FPGA 得到更广泛使用的重要见解。例如，如果应用程序不能以最佳方式提交请求，FPGA 提供的巨大潜在性能增益在实践中会大大降低，这并不总是可能的，并且可能需要对应用程序进行重大更改。同样，一些现有的云部署结果证明使用了一种非常不平衡的架构：一个强大的 FPGA 连接到一个不那么强大的 CPU。结果是 CPU 无法为 FPGA 产生足够的负载，这可能会消除所有性能提升，甚至可能导致系统成本更高。在这篇论文中，我们报告了将 FPGA 纳入搜索引擎的广泛研究和开发工作，并分析了遇到的问题及其实际影响。我们预计这些结果将为 FPGA 在现有系统中的端到端集成提供重要见解，从而为未来 FPGA 的开发和部署提供信息。