Topic
I/O virtualization
About: I/O virtualization is a research topic. Over the lifetime, 176 publications have been published within this topic receiving 7183 citations. The topic is also known as: VIO.
Papers published on a yearly basis
Papers
Proceedings Article•
25 Jun 2001TL;DR: Results indicate that with optimizations, VMware Workstation’s hosted virtualization architecture can match native I/O throughput on standard PCs.
Abstract: Virtual machines were developed by IBM in the 1960’s to provide concurrent, interactive access to a mainframe computer. Each virtual machine is a replica of the underlying physical machine and users are given the illusion of running directly on the physical machine. Virtual machines also provide benefits like isolation and resource sharing, and the ability to run multiple flavors and configurations of operating systems. VMwareWorkstation brings such mainframe-class virtual machine technology to PC-based desktop and workstation computers. This paper focuses on VMware Workstation’s approach to virtualizing I/O devices. PCs have a staggering variety of hardware, and are usually pre-installed with an operating system. Instead of replacing the pre-installed OS, VMware Workstation uses it to host a user-level application (VMApp) component, as well as to schedule a privileged virtual machine monitor (VMM) component. The VMM directly provides high-performance CPU virtualization while the VMApp uses the host OS to virtualize I/O devices and shield the VMM from the variety of devices. A crucial question is whether virtualizing devices via such a hosted architecture can meet the performance required of high throughput, low latency devices. To this end, this paper studies the virtualization and performance of an Ethernet adapter on VMware Workstation. Results indicate that with optimizations, VMware Workstation’s hosted virtualization architecture can match native I/O throughput on standard PCs. Although a straightforward hosted implementation is CPU-limited due to virtualization overhead on a 733 MHz Pentium R III system on a 100 Mb/s Ethernet, a series of optimizations targeted at reducing CPU utilization allows the system to match native network throughput. Further optimizations are discussed both within and outside a hosted architecture.
824 citations
IBM1
TL;DR: The virtio API layer is described as implemented in Linux, then the vring implementation, and finally its embodiment in a PCI device for simple adoption on otherwise fully-virtualized guests.
Abstract: The Linux Kernel currently supports at least 8 distinct virtualization systems: Xen, KVM, VMware's VMI, IBM's System p, IBM's System z, User Mode Linux, lguest and IBM's legacy iSeries. It seems likely that more such systems will appear, and until recently each of these had its own block, network, console and other drivers with varying features and optimizations.The attempt to address this is virtio: a series of efficient, well-maintained Linux drivers which can be adapted for various different hypervisor implementations using a shim layer. This includes a simple extensible feature mechanism for each driver. We also provide an obvious ring buffer transport implementation called vring, which is currently used by KVM and lguest. This has the subtle effect of providing a path of least resistance for any new hypervisors: supporting this efficient transport mechanism will immediately reduce the amount of work which needs to be done. Finally, we provide an implementation which presents the vring transport and device configuration as a PCI device: this means guest operating systems merely need a new PCI driver, and hypervisors need only add vring support to the virtual devices they implement (currently only KVM does this).This paper will describe the virtio API layer as implemented in Linux, then the vring implementation, and finally its embodiment in a PCI device for simple adoption on otherwise fully-virtualized guests. We'll wrap up with some of the preliminary work to integrate this I/O mechanism deeper into the Linux host kernel.
608 citations
11 Jun 2005
TL;DR: Xenoprof is presented, a system-wide statistical profiling toolkit implemented for the Xen virtual machine environment that will facilitate a better understanding of performance characteristics of Xen's mechanisms allowing the community to optimize the Xen implementation.
Abstract: Virtual Machine (VM) environments (e.g., VMware and Xen) are experiencing a resurgence of interest for diverse uses including server consolidation and shared hosting. An application's performance in a virtual machine environment can differ markedly from its performance in a non-virtualized environment because of interactions with the underlying virtual machine monitor and other virtual machines. However, few tools are currently available to help debug performance problems in virtual machine environments.In this paper, we present Xenoprof, a system-wide statistical profiling toolkit implemented for the Xen virtual machine environment. The toolkit enables coordinated profiling of multiple VMs in a system to obtain the distribution of hardware events such as clock cycles and cache and TLB misses. The toolkit will facilitate a better understanding of performance characteristics of Xen's mechanisms allowing the community to optimize the Xen implementation.We use our toolkit to analyze performance overheads incurred by networking applications running in Xen VMs. We focus on networking applications since virtualizing network I/O devices is relatively expensive. Our experimental results quantify Xen's performance overheads for network I/O device virtualization in uni- and multi-processor systems. With certain Xen configurations, networking workloads in the Xen environment can suffer significant performance degradation. Our results identify the main sources of this overhead which should be the focus of Xen optimization efforts. We also show how our profiling toolkit was used to uncover and resolve performance bugs that we encountered in our experiments which caused unexpected application behavior.
587 citations
TL;DR: This paper surveys a variety of established and emerging techniques for I/O virtualization and outlines their associated problems and challenges, then details the architecture of VT-d and describes how it enables the industry to meet the future challenges of I/o virtualization.
Abstract: Intel ® Virtualization Technology Δ for Directed I/O (VT-d) is the next important step toward comprehensive hardware support for the virtualization of Intel ® platforms. VT-d extends Intel's Virtualization Technology (VT) roadmap from existing support for IA-32 (VT-x) (1) and Itanium ® processor (VT-i) (2) virtualization to include new support for I/O-device virtualization. This paper surveys a variety of established and emerging techniques for I/O virtualization and outlines their associated problems and challenges. We then detail the architecture of VT-d and describe how it enables the industry to meet the future challenges of I/O virtualization.
541 citations
Proceedings Article•
30 May 2006TL;DR: The overall impact of these optimizations is an improvement in transmit performance of guest domains by a factor of 4.4, and support for guest operating systems to effectively utilize advanced virtual memory features such as superpages and global page mappings.
Abstract: In this paper, we propose and evaluate three techniques for optimizing network performance in the Xen virtualized environment. Our techniques retain the basic Xen architecture of locating device drivers in a privileged 'driver' domain with access to I/O devices, and providing network access to unprivileged 'guest' domains through virtualized network interfaces.
First, we redefine the virtual network interfaces of guest domains to incorporate high-level network offfload features available in most modern network cards. We demonstrate the performance benefits of high-level offload functionality in the virtual interface, even when such functionality is not supported in the underlying physical interface. Second, we optimize the implementation of the data transfer path between guest and driver domains. The optimization avoids expensive data remapping operations on the transmit path, and replaces page remapping by data copying on the receive path. Finally, we provide support for guest operating systems to effectively utilize advanced virtual memory features such as superpages and global page mappings.
The overall impact of these optimizations is an improvement in transmit performance of guest domains by a factor of 4.4. The receive performance of the driver domain is improved by 35% and reaches within 7% of native Linux performance. The receive performance in guest domains improves by 18%, but still trails the native Linux performance by 61%. We analyse the performance improvements in detail, and quantify the contribution of each optimization to the overall performance.
366 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 3 |
| 2019 | 12 |
| 2018 | 5 |
| 2017 | 8 |
| 2016 | 10 |