research-article Share on Hypercallbacks: Decoupling Policy Decisions and Execution Authors: Nadav Amit VMware Research Group VMware Research GroupView Profile , Michael Wei VMware Research Group VMware Research GroupView Profile , Cheng-Chun Tu VMware VMwareView Profile Authors Info & Claims HotOS '17: Proceedings of the 16th Workshop on Hot Topics in Operating SystemsMay 2017 Pages 37–41https://doi.org/10.1145/3102980.3102987Published:07 May 2017Publication History 2citation337DownloadsMetricsTotal Citations2Total Downloads337Last 12 Months21Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

As the performance overhead associated with CPU and memory virtualization becomes largely negligible, research efforts are directed toward reducing the I/O virtualization overhead, which mainly comes from two sources: DMA set-up and payload copy, and interrupt delivery. The advent of SRIOV and MRIOV effectively reduces the DMA-related virtualization overhead to a minimum. Therefore, the last battleground for minimizing virtualization overhead is how to directly deliver every interrupt to its target VM without involving the hypervisor.

Disaggregation of hardware resources that are traditionally embedded within individual servers into separate resource pools is an emerging architectural trend in hyperscale data center design, as exemplified by Facebook's disaggregated rack architecture. This paper presents the design, implementation and evaluation of a PCIe-based rack area network system called Marlin, which is designed to support the communications needs of disaggregated racks. By virtue of being based on PCIe, Marlin presents a memory-based addressing model for both I/O device sharing among multiple hosts and inter-host communications, and as a result offers hardware- based remote direct memory access (HRDMA) as a first-class communications primitive between servers within a rack. Marlin supports socket-based communications for legacy network applications and cross-machine zero memory copying for applications designed specifically to take full advantage of Marlin. Empirical measurements on a fully operational Marlin prototype based on 4-lane Gen3 PCIe technology show that the one-way kernel-to-kernel latency is 8.5μsec and the end-to- end sustainable TCP throughput is 19.6 Gbps.

A distinguishing characteristic of a software-defined network is separation of the network's control plane from its data plane. Especially when the granularity of control is an individual network flow, such separation entails frequent communications between these two planes. This communication pattern demands the same level of resilience from the control plane as that from the data plane, and thus calls into question the conventional out-of-band control network design as used in many existing SDN systems. Peregrine is an Ethernet-based software-defined network that was originally designed as the internal network of a container computer, and unifies storage access, inter-server communication, and network control into a single network comprising only commodity off-the-shelf Ethernet switches. To fully utilize all available physical network links, Peregrine treats the physical network as an explicitly routed mesh and equalizes the loads of its links using a global load-balancing routing algorithm running on a centralized controller. The in-band control architecture of Peregrine leads to two issues: (1) how to evolve a Peregrine network from its initial bootstrapping mode to the explicit routing mode at run time, and (2) how to support fast fail-over for physical failures that break both the control and data plane. This paper describes how Peregrine addresses these two issues, and shows its effectiveness with performance measurements collected from a fully operational test-bed.

Virtualization allows flexible mappings between physical resources and virtual entities, and improves allocation efficiency and agility. Unfortunately, most existing virtualization technologies are limited to resources in a single host. This paper presents the design, implementation and evaluation of a multi-host I/O device virtualization system called Ladon, which enables I/O devices to be shared among virtual machines running on multiple hosts in a secure and efficient way. Specifically, Ladon uses a PCIe network to connect multiple servers with PCIe devices and allows VMs running on these servers to directly interact with these PCIe devices without interfering with one another. Through an evaluation of a fully operational Ladon prototype, we show that there is no throughput and latency penalty of the multi-host I/O virtualization enabled by Ladon compared to those of the existing single-host I/O virtualization technology.

Networks today rely on middleboxes to provide critical performance, security, and policy compliance capabilities. Achieving these benefits and ensuring that the traffic is directed through the desired sequence of middleboxes requires significant manual effort and operator expertise. In this respect, Software-Defined Networking (SDN) offers a promising alternative. Middleboxes, however, introduce new aspects (e.g., policy composition, resource management, packet modifications) that fall outside the purvey of traditional L2/L3 functions that SDN supports (e.g., access control or routing).

ITRI container computer is a modular computer designed to be a building block for constructing cloud-scale data centers. Rather than using a traditional data center network architecture, which is typically based on a combination of Layer 2 switches and Layer 3 routers, ITRI containercomputer's internal interconnection fabric, called Peregrine, is specially architected to meet the scalability, fast fail-over and multi-tenancy requirements of these data centers. Peregrine is an all-Layer 2 network that is designed to support up to one million Layer 2 end points, provide quick recovery from any single network link/device failure, and incorporate dynamic load-balancing routing to make the best of all physical network links. Finally, the Peregrine architecture is implementable using only off-the-shelf commodity Ethernet switches. This paper describes the design and implementation of a fully operational Peregrine prototype, which is built on a folded Clos physical network topology, and the results and analysis of a performance evaluation study based on measurements taken on this prototype.

As the service requirements of network applications shift from high throughput to high media quality, interactivity, and responsiveness, the definition of QoE (Quality of Experience) has become multidimensional. Although it may not be difficult to measure individual dimensions of the QoE, how to capture users' overall perceptions when they are using network applications remains an open question. In this paper, we propose a framework called OneClick to capture users' perceptions when they are using network applications. The framework only requires a subject to click a dedicated key whenever he/she feels dissatisfied with the quality of the application in use. OneClick is particularly effective because it is intuitive, lightweight, efficient, time-aware, and application-independent. We use two objective quality assessment methods, PESQ and VQM, to validate OneClick's ability to evaluate the quality of audio and video clips. To demonstrate the proposed framework's efficiency and effectiveness in assessing user experiences, we implement it on two applications, one for instant messaging applications, and the other for first- person shooter games. A Flash implementation of the proposed framework is also presented.