Network Function Virtualization (NFV) offers service delivery flexibility and reduces overall costs by running service function chains (SFCs) on commodity servers with many cores. Existing solutions for placing SFCs in one server treat all CPU cores as equal and allocate isolated CPU cores to network functions (NFs). However, advanced servers often adopt Non-Uniform Memory Access (NUMA) architecture to improve the scalability of many-core systems. CPU cores are grouped into nodes, incurring performance degradation due to cross-node memory access and intra-node resource contention. Our evaluation shows that randomly selecting cores to place NFs in an SFC could suffer from 39.2 percent lower throughput comparing to an optimal placement solution. In this article, we propose Octans , an NFV orchestrator to achieve maximum aggregate throughput of all SFCs in many-core systems. Octans first formulates the optimization problem as a Non-Linear Integer Programming (NLIP) Model. Then we identify the key factor for problem solving as evaluating the throughput drop of an NF caused by other NFs in the same SFC or different SFCs, i.e., performance drop index , and propose a formal and accurate prediction model based on system level performance metrics. Finally, we propose two online algorithms to quickly find near-optimal placement solutions for one-time and incremental deployment. Extensive evaluation on a prototype implementation shows that Octans significantly improves the aggregate throughput comparing to two state-of-the-art placement solutions by 27.1 $\sim$ 45.2 percent for one-time deployment and by 20.9 $\sim$ 38.1 percent for incremental deployment, with very low prediction errors. Moreover, Octans could quickly find a near-optimal placement solution with tiny optimality gap.

中文翻译：

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Octans：多核系统中服务功能链的最佳放置

网络功能虚拟化（NFV）通过在具有多个核心的商用服务器上运行服务功能链（SFC），提供了服务交付灵活性，并降低了总体成本。用于将SFC放在一台服务器中的现有解决方案将所有CPU内核视为相等，并将隔离的CPU内核分配给网络功能（NF）。但是，高级服务器通常采用非统一内存访问（NUMA）架构来提高多核系统的可伸缩性。CPU核心分为多个节点，由于跨节点内存访问和节点内资源争用而导致性能下降。我们的评估表明，与最佳放置解决方案相比，随机选择将NF放置在SFC中的核心可能会降低39.2％的吞吐量。在本文中，我们提出Octans NFV协调器，以实现多核系统中所有SFC的最大总吞吐量。 Octans首先将优化问题表述为非线性整数规划（NLIP）模型。然后，我们确定解决问题的关键因素是评估同一SFC或不同SFC中其他NF导致的NF吞吐量下降。绩效下降指数 ，并根据系统级性能指标提出一种正式而准确的预测模型。最后，我们提出了两种在线算法，可以快速找到一次性和增量部署的最佳解决方案。对原型实现的广泛评估表明：Octans 与两个最先进的贴装解决方案相比，显着提高了总吞吐量 $ \ sim $ 一次性部署占45.2％，到20.9％ $ \ sim $ 38.1％的增量部署，具有极低的预测误差。而且，Octans 可以快速找到具有最佳间隙的最佳放置解决方案。