Certain new ascendant data center workloads can absorb some degradation in network service, not needing fully reliable data transport and/or their fair-share of network bandwidth. This opens up opportunities for superior network and infrastructure multiplexing by having this flexible traffic cede capacity under congestion to regular traffic with stricter needs. We posit there is opportunity in network service primitives which permit degradation within certain bounds, such that flexible traffic still receives an acceptable level of service, while benefiting from its weaker requirements. We propose two primitives, namely guaranteed partial delivery and bounded deprioritization. We design a budgeting algorithm to provide guarantees relative to their fair share, which is measured via probing. The requirement of budgeting and probing limits the algorithm's applicability to large flexible flows. We evaluate our algorithm with large flexible flows and for three workloads of regular flows of small size, large size and a distribution of sizes. Across the workloads, our algorithm achieves less speed-up of regular flows than fixed prioritization, especially for the small flows workload (1.25x vs. 6.82 in the 99th %-tile). Our algorithm provides better guarantees in the workload with large regular flows (with 14.5% vs. 32.5% of flexible flows being slowed down beyond their guarantee). However, it provides not much better or even slightly worse guarantees for the other two workloads. The ability to enforce guarantees is influenced by flow fair share interdependence, measurement inaccuracies and dependency on convergence. We observe that priority changes to probe or to deprioritize causes queue shifts which deteriorate guarantees and limit possible speed-up, especially of small flows. We find that mechanisms to both prioritize traffic and track guarantees should be as non-disruptive as possible.
翻译:某些新的升迁数据中心工作量可以吸收网络服务的某些退化,不需要完全可靠的数据传输和(或)网络带宽的公平分配。这为高级网络和基础设施的多重化提供了机会,因为将这种灵活的交通量缩放能力压缩到经常交通的拥挤状态,导致更严格的需求。我们假设网络服务原始化中存在一些机会,允许某些范围内的退化,使灵活的交通量仍然得到可接受的服务水平,同时受益于其较弱的要求。我们建议两种原始方法,即保证部分交付和受约束的递解压。我们设计了一种预算算法,以提供相对于其公平份额的保障,而这种公平比例是通过验证衡量来衡量的。需要编制预算和验证限制了算法对大规模灵活流动的可适用性。我们用大量灵活流动和三次正常流动的算法来评估我们的算法,因此,灵活的交通量的增速比固定的排序要慢,特别是小流量(1.25x优先级比6.82分级),我们设计了一个相对公平的计算方法,对于不易递增的流量来说,我们的算法更能提供更大的保证,对于经常流动来说,特别是正常流动的递减的流量的流量,但顺流的递减速度比为14。