User-level Network Research Articles

Advancements in Network Attached Storage (NAS) for Mobile Devices: Technological Developments and Performance Assessment

Network-attached storage (NAS) technology has emerged as a vital solution in the evolving landscape of data management and storage. With the exponential growth of data and the increasing demand for efficient, scalable storage solutions, NAS systems offer a centralized, cost-effective, and flexible alternative to traditional storage methods. This paper explores the application and advantages of NAS technology in various scenarios, from home and small business environments to large enterprises. It highlights the key strengths of NAS systems in optimizing data storage, ensuring data security, and facilitating cross-device sharing. The study delves into the architectural components of NAS, including file systems, RAID configurations, and network protocols, to demonstrate how these technologies enhance storage performance and reliability. Technical details on NAS system design, such as the integration of advanced file systems and user-level networking technologies, are discussed to showcase their impact on data transfer efficiency and overall system performance. Experimental results validate the effectiveness of NAS in different environments, illustrating its ability to provide high availability, data redundancy, and low-latency data access. The findings underscore NAS technology’s potential as a versatile and scalable storage solution, with recommendations for future research focused on developing new file systems, optimizing network protocols, and exploring edge computing integrations to further enhance NAS capabilities.

Kernel vs. User-Level Networking: Don't Throw Out the Stack with the Interrupts

This paper reviews the performance characteristics of network stack processing for communication-heavy server applications. Recent literature often describes kernel-bypass and user-level networking as a silver bullet to attain substantial performance improvements, but without providing a comprehensive understanding of how exactly these improvements come about. We identify and quantify the direct and indirect costs of asynchronous hardware interrupt requests (IRQ) as a major source of overhead. While IRQs and their handling have a substantial impact on the effectiveness of the processor pipeline and thereby the overall processing efficiency, their overhead is difficult to measure directly when serving demanding workloads. This paper presents an indirect methodology to assess IRQ overhead by constructing preliminary approaches to reduce the impact of IRQs. While these approaches are not suitable for general deployment, their corresponding performance observations indirectly confirm the conjecture. Based on these findings, a small modification of a vanilla Linux system is devised that improves the efficiency and performance of traditional kernel-based networking significantly, resulting in up to 45% increased throughput without compromising tail latency. In case of server applications, such as web servers or Memcached, the resulting performance is comparable to using kernel-bypass and user-level networking when using stacks with similar functionality and flexibility.

Social influence and the choice of product upgrades: evidence from virtual product adoption in online games

PurposePrevious studies on social influence and virtual product adoption have mainly taken users’ purchase behavior as a dichotomous variable (i.e. purchasing or not). Given the prevalence of competing versions (basic vs upgraded) of a virtual product in online communities, this paper investigated the differences in the effect of social influence on users’ adoption of basic and upgraded choices of a virtual product. It also examined how the effect varies with users’ social status and user-level network density.Design/methodology/approachA natural experiment was conducted in an online game community. Two competing versions (basic vs upgraded) of a virtual product were provided for in-game purchase while a random set of users selected from 897,765 players received the notification of their friends’ adoption information. A competing-risk model was used to test the hypotheses.FindingsSocial influence exerts a stronger positive effect on users’ adoption of the upgraded virtual product than of the basic virtual product. Middle-status users have the greatest (least) susceptibility to social influence in adopting the upgraded (basic) virtual product than low- and high-status users. User’s network density enhances the effect of social influence on adoption of both virtual products, even more for the upgraded one.Originality/valueThis research contributes to the social influence and product adoption literature by disentangling the different effects of social influence on basic and upgraded versions of a virtual product. It also identifies the boundary conditions that social influence works for each version of the virtual product.

Kernel vs. User-Level Networking: Don't Throw Out the Stack with the Interrupts

This paper reviews the performance characteristics of network stack processing for communication-heavy server applications. Recent literature often describes kernel-bypass and user-level networking as a silver bullet to attain substantial performance improvements, but without providing a comprehensive understanding of how exactly these improvements come about. We identify and quantify the direct and indirect costs of asynchronous hardware interrupt requests (IRQ) as a major source of overhead. While IRQs and their handling have a substantial impact on the effectiveness of the processor pipeline and thereby the overall processing efficiency, their overhead is difficult to measure directly when serving demanding workloads. This paper presents an indirect methodology to assess IRQ overhead by constructing preliminary approaches to reduce the impact of IRQs. While these approaches are not suitable for general deployment, their corresponding performance observations indirectly confirm the conjecture. Based on these findings, a small modification of a vanilla Linux system is devised that improves the efficiency and performance of traditional kernel-based networking significantly, resulting in up to 45% increased throughput without compromising tail latency. In case of server applications, such as web servers or Memcached, the resulting performance is comparable to using kernel-bypass and user-level networking when using stacks with similar functionality and flexibility.

Light: A Compatible, high-performance and scalable user-level network stack

As the number of CPU cores and the speed of Ethernet NICs keep increasing on server machines, the network stack in the kernel has become the bottleneck for applications demanding very high throughput and ultra-low latency. Recently there is a trend towards moving the network stack out of the kernel. However, most kernel-bypass network stacks discard POSIX APIs that legacy applications have been built on, and the intricate work of transplanting applications brings the barrier to real-world deployment of kernel-bypass stacks. In this work, we propose Light, a novel user-level network stack, which not only gains highly scalable performance on multi-core server, but also achieves compatibility with legacy applications. For compatibility, Light realizes efficient blocking APIs in the user space, intercepts network-related APIs in a non-intrusive manner, and uses the FD space separation technique for proper API redirection. For high performance and scalability, Light adopts lock-free shared queue based inter-process communication and full connection affinity to reduce overheads of system call, cache miss, etc. Experiments demonstrate that many types of legacy applications could run on Light without modifying their source code. Compared with the latest kernel stack, Nginx on Light achieves up to 2.86× throughput and 78.2% lower tail latency (99.9th percentile) with 14 CPU cores.

A Hierarchical Network with User Memory Matrix for Long Sequence Recommendation

In many recommendation scenarios, the interactions between users and items are divided into a series of sessions according to the time interval. The traditional Recurrent Neural Network has some shortcomings, such as limited memory ability, inflexible access to memory data, and obvious deficiency in feature capture for long sequences. To deal with the mentioned issues, we propose a hierarchical network with user memory matrix, named HNUM2, which utilizes the memory network to store users' long-term and short-term interests. The memory network is more flexible to access memory data, which can solve the problem of insufficient capture of long sequence features. The proposed model is a hierarchical recommendation algorithm, which consists of two layers. The first layer is the session-level GRU model, which obtains the sequence characteristics of the current session to predict the next item. The second layer is the user-level memory network model which exploits the attention mechanism and incorporates the write module and read module. The experimental results on two public available datasets show that HNUM2 has achieved significant performance improvement comparing to the state-of-the-art methods.

Giddy Ion Reloaded: Desktop Manager, Optimizer with Multi Utility Tool

The performance of our computer is vital in fulfilling the task of the user. The paper presents a solution for maintaining the performance of the computer specifically computers with Windows operating systems. In this article, the fundamental difference and problem of the Windows operating system are defined which roots in the architectural design of using single configuration storage. The security hole of windows authentication, the exploitation of Microsoft EFS, and the acquisition of password hashes from Microsoft SAM are also discussed. Various existing utility software is evaluated to investigate if they meet the user define criteria. This paper also proposes a user-level implementation of the AES 256 encryption algorithm for securing user files and a Network Blocking algorithm based on ARP Spoofing techniques that provide a user-level network monitoring capability. The proposed application is called “Giddy-ION Reloaded” which consists of four main modules; machine information acquisition and monitoring, machine optimization, machine cleaning, and tools module that is divided into submodule; encryption and decryption, network monitoring, desktop management, network optimization/ control, and task automation. The testing was conducted with the participants coming from a computer college, continuing education trainer/faculty, and various IT experts. The response from these groups was statistically treated and analyzed, where the Giddy ION rank top and shows promising results. The study is limited to windows machines with 64-bit support architecture. The developed application is ready for implementation and deployment as evidenced by its high overall performance rating as evaluated by the participants against the ISO 25010 standards.

DLibOS

A long body of research work has led to the conjecture that highly efficient IO processing at user-level would necessarily violate protection. In this paper, we debunk this myth by introducing DLibOS a new paradigm that consists of distributing a library OS on specialized cores to achieve performance and protection at the user-level. Its main novelty consists of leveraging network-on-chip to allow hardware message passing, rather than context switches, for communication between different address spaces. To demonstrate the feasibility of our approach, we implement a driver and a network stack at user-level on a Tilera many-core machine. We define a novel asynchronous socket interface and partition the memory such that the reception, the transmission and the application modify isolated regions. Our high performance results of 4.2 and 3.1 million requests per second obtained on a webserver and the Memcached applications, respectively, confirms the relevance of our design decisions. Finally, we compare DLibOS against a non-protected user-level network stack and show that protection comes at a negligible cost.

PARSEC3.0

Benchmarks play a very important role in accelerating the development and research of CMP. As one of them, the PARSEC suite continues to be updated and revised over and over again so that it can offer better support for researchers. The former versions of PARSEC have enough workloads to evaluate the property of CMP about CPU, cache and memory, but it lacks of applications based on network stack to assess the performance of CMPs in respect of network. In this work, we introduce PARSEC3.0, a new version of PARSEC suite that implements a user-level network stack and generates three network workloads with this stack to cover network domain. We explore the input sets of splash-2 and expand them to multiple scales, a.k.a, splash-2x. We integrate splash-2 and splash-2x into PARSEC framework so that researchers use these benchmark suite conveniently. Finally, we evaluate the u-TCP/IP stack and new network workloads, and analyze the characterizes of splash-2 and splash-2x

The IX Operating System

The conventional wisdom is that aggressive networking requirements, such as high packet rates for small messages and μs-scale tail latency, are best addressed outside the kernel, in a user-level networking stack. We present ix , a dataplane operating system that provides high I/O performance and high resource efficiency while maintaining the protection and isolation benefits of existing kernels. ix uses hardware virtualization to separate management and scheduling functions of the kernel (control plane) from network processing (dataplane). The dataplane architecture builds upon a native, zero-copy API and optimizes for both bandwidth and latency by dedicating hardware threads and networking queues to dataplane instances, processing bounded batches of packets to completion, and eliminating coherence traffic and multicore synchronization. The control plane dynamically adjusts core allocations and voltage/frequency settings to meet service-level objectives. We demonstrate that ix outperforms Linux and a user-space network stack significantly in both throughput and end-to-end latency. Moreover, ix improves the throughput of a widely deployed, key-value store by up to 6.4× and reduces tail latency by more than 2× . With three varying load patterns, the control plane saves 46%--54% of processor energy, and it allows background jobs to run at 35%--47% of their standalone throughput.

Extreme-scale computing services over MPI: Experiences, observations and features proposal for next-generation message passing interface

The message passing interface (MPI) is one of the most portable high-performance computing (HPC) programming models, with platform-optimized implementations typically delivered with new HPC systems. Therefore, for distributed services requiring portable, high-performance, user-level network access, MPI promises to be an attractive alternative to custom network portability layers, platform-specific methods, or portable but less performant interfaces such as BSD sockets. In this paper, we present our experiences in using MPI as a network transport for a large-scale distributed storage system. We discuss the features of MPI that facilitate adoption as well as aspects which require various workarounds. Based on use cases, we derive a wish list for both MPI implementations and the MPI forum to facilitate the adoption of MPI by large-scale persistent services. The proposals in the wish list go beyond the sole needs of distributed services; we contend that they will benefit mainstream HPC applications at extreme scales as well.

Speech Quality Evaluation Based Codec for VoIP Over 802.11P

Voice over Internet Protocol (VoIP) may provide good services through Vehicular ad hoc networks (VANETs) platform by providing services to many application scenarios range from safety to comfort. However, VANETs networks introduce many challenges for supporting voice with QoS requirements. In this paper, our study is based on Inter-Vehicle voice streaming rely on multi-hop fashion. For this task, a performance evaluation of various audio CODECs will be analyzed by mean of simulations. Furthermore, we test the impact of network environment on QoS metrics. To achieve good results, CODECs behaviour is tested by using mobility information obtained from vehicular traffic generator. The mobility model is based on the real road maps of an urban environment. Focusing on inter-vehicular voice traffic quality, we provide simulations results in terms of both user level (MOS) metrics and network level (such as Losses). According to this performance evaluation, we show that G.723.1 CODEC worked well in the urban VANET environment.

Towards full network virtualization in horizontal IaaS federation: security issues

Horizontal IaaS federation exploits datacenter for federation of IaaS provider by supplying virtual nodes (e.g. virtual machines, virtual switches, and virtual routers) and virtual links. Today's datacenters for cloud computing do not supply full network virtualization in terms of user-level network management and user-agreed network topology. The datacenters lack the basic security services required for the collocation of tenants' virtual networks. The network virtualization research projects from academia and industry support full network virtualization but lack the basic security services required for the collocation of tenants' virtual networks. This paper investigates the security issues in four areas namely, (a) monolithic IaaS cloud, (b) network virtualization research projects, (c) datacenter network virtualization and (d) virtual resources to incorporate full network virtualization environment in horizontal IaaS federation. Further, it presents the security related qualitative comparisons of datacenters, network virtualization research projects and virtual resources to incorporate full network virtualization in horizontal IaaS federation.

Application-specific service technologies for commodity operating systems in real-time environments

In order to eliminate the costs of proprietary systems and special purpose hardware, many real-time and embedded computing platforms are being built on commodity operating systems and generic hardware. Unfortunately, many such systems are ill-suited to the low-latency and predictable timing requirements of real-time applications. This article, therefore, focuses on application-specific service technologies for low-cost commodity operating systems and hardware, so that real-time service guarantees can be met. We describe contrasting methods to deploy first-class services on commodity systems that are dispatched with low latency and execute asynchronously according to bounds on CPU, memory, and I/O device usage. Specifically, we present a “user-level sandboxing” (ULS) mechanism that relies on hardware protection to isolate application-specific services from the core kernel. This approach is compared with a hybrid language and runtime protection scheme, called SafeX , that allows untrusted services to be dynamically linked and loaded into a base kernel. SafeX and ULS have been implemented on commodity Linux systems. Experimental results have shown—that both approaches are capable of reducing service violations (and, hence, better qualities of service) for real-time tasks, compared to traditional user-level methods of service deployment in process-private address spaces. ULS imposes minimal additional overheads on service dispatch latency compared to SafeX, with the advantage that it does not require application-specific services to execute in the trusted kernel domain. As evidence of the potential capabilities of ULS, we show how a user-level networking stack can be implemented to avoid data copying via the kernel and allow packet processing without explicit process scheduling. This improves throughput and reduces jitter.

Special issue on virtualization

Virtualization has always been an enabler for efficient management in networking environments. The recent developments in hardware and software virtualization that emerged in the last few years now open new and very promising perspectives to more flexible networks, paving the way for new advanced services. However, to enable these evolutions to become one of the core building blocks of the future Internet, many challenges still need to be addressed. In this special issue of the International Journal of Network Management, three papers present different approaches to virtualization and its utilization for improving networks and their management. The paper entited ‘Using Virtual Topologies to Manage Inter-domain QoS in Next Generation Networks’ by Madeira et al. proposes the virtualization of network topologies to ease inter-domain quality of service management. The paper entitled ‘Specifying and provisioning Virtual Infrastructures with HIPerNET’, by Anhalt et al., extends the model of virtualization to both computing resources and networks so as to enable full infrastructure virtualization. Finally, the paper entitled ‘Characterizing User-level Network Virtualization: Performance, Overheads and Limits’, by Tsugawa et al., provides a study on the performance of virtualized networks built as overlays among standard operating systems nodes. This special issue on ‘Network Virtualization and Its Management’ received ten submissions from around the world, out of which the three papers mentioned above have been selected. Every submitted paper has been reviewed by four experts from a committee composed of nine researchers in the field.

Eager Data Transfer Mechanism for Reducing Communication Latency in User-Level Network Protocols

Abstract: Clusters have become a popular alternative for building high-performance parallel computing systems. Today’s high-performance system area network (SAN) protocols such as VIA and IBA significantly reduce user-to-user communication latency by implementing protocol stacks outside of operating system kernel. However, emerging parallel applications require a significant improvement in communication latency. Since the time required for transferring data between host memory and network interface (NI) make up a large portion of overall communication latency, the reduction of data transfer time is crucial for achieving low-latency communication. In this paper, Eager Data Transfer (EDT) mechanism is proposed to reduce the time for data transfers between the host and network interface. The EDT employs cache coherence interface hardware to directly transfer data between the host and NI. An EDT-based network interface was modeled and simulated on the Linux-based, complete system simulation environment, Linux/SimOS. Our simulation results show that the EDT approach significantly reduces the data transfer time compared to DMA-based approaches. The EDT-based NI attains 17% to 38% reduction in user-to-user message time compared to the cache-coherent DMA-based NIs for a range of message sizes (64 bytes ~ 4 Kbytes) in a SAN environment.

Software Distributed Shared Memory: a VIA-based implementation and comparison of sequential consistency with home-based lazy release consistency

A Distributed Shared Memory (DSM) system provides a distributed application with a shared virtual address space. This article proposes a design for implementing the DSM communication layer on top of the Virtual Interface Architecture (VIA), an industry standard for user-level networking protocols on high-speed clusters. User-level communication protocols operate in user mode, thus removing the operating system kernel's overhead from the critical communication pass, and significantly diminishing communication overhead as a result. We analyze VIA's facilities and limitations in order to ascertain which implementation trade-offs can be best applied to our development of an efficient communication substrate optimized for DSM requirements. We then implement a multithreaded version of the Home-based Lazy Release Consistency (HLRC) protocol on top of this substrate. In addition, we compare the performance of this HLRC protocol with that of the Sequential Consistency (SC) protocol in which a MultiView (MV) memory mapping technique was used. This technique enables a fine-grained access to shared memory, while still relying on the virtual memory hardware to track memory accesses. We perform an ‘apple-to-apple’ comparison on the same testbed environment and benchmark suite, and investigate the effectiveness and scalability of both protocols. Copyright © 2005 John Wiley & Sons, Ltd.

Application performance on the Direct Access File System

The Direct Access File System (DAFS) is a distributed file system built on top of direct-access transports (DAT). Direct-access transports are characterized by using remote direct memory access (RDMA) for data transfer and user-level networking. The motivation behind the DAT-enabled distributed file system architecture is the reduction of the CPU overhead on the I/O data path.We have created an implementation of DAFS for the FreeBSD platform. In this paper we describe the performance evaluation study of DAFS that we have performed using this software. The goal of this study is to determine whether the architecture of DAFS brings any fundamental performance benefits to applications compared to traditional distributed file systems, such as NFS. We perform comparison of DAFS to a version of NFS optimized to reduce the I/O overhead. In order to thoroughly understand the impact of DAFS on application performance, we consider a diverse range of applications workloads.We conclude that DAFS can accomplish superior performance for latency-sensitive applications, outperforming NFS by up to a factor of 2. Bandwidth-sensitive applications do equally well on both systems, unless they are CPU-intensive, in which case they perform better on DAFS. We also found that RDMA is a less restrictive mechanism to achieve copy avoidance than that used by the optimized NFS.

The design of QoS guarantee network subsystem

The current Internet service model treats all requests equivalently, there are great need of Quality of Service guarantee for real-time traffic. The paper covers two QoS guarantee methods: Integrated Service and Differentiated Service, and discusses its interoperation problems. To estimate the efficient bandwidth of traffic flow requirement, we use Fractional Brownian Motion model to simulate the self-similar traffic. The algorithm can plenty utilize bandwidth. When combining with the user-level network processing and interoperation of Intserv and Diffserv, the new network architecture can have better QoS guarantees. The experiments prove this result.

Design Alternatives for Virtual Interface Architecture and an Implementation on IBM Netfinity NT Cluster

The Virtual Interface Architecture (VIA) specification has been developed to standardize user-level network interfaces that provide low-latency, high-bandwidth communications. Few hardware and software implementations of VIA exist. Since the VIA specification is flexible, different choices exist for implementing various components of VIA such as doorbells, address translation methods, and completion queues. Although previous studies have evaluated the overall performance of different VIA implementations, there has not been a comparative study on the performance of VIA components. In this paper, we evaluate and compare the performance of different implementations of essential VIA components. We discuss the pros and cons of each design approach and describe the required support for implementing each of them. Then, we discuss an experimental implementation of the Virtual Interface Architecture for the IBM SP Switch-Connected NT cluster, one of the newest clustering platforms available. We discuss different design issues involved in this implementation. In particular, we explain how the virtual-to-physical address translation is implemented efficiently with a minimum Network Interface Card (NIC) memory requirement. We show how caching the VIA descriptors on the NIC can reduce the communication latency. We also present an efficient scheme for implementing the VIA doorbells without any hardware support. We provide a comprehensive performance evaluation study and discuss the impact of several hardware improvements on the performance of our implementation. The performance of the implemented VIA surpasses that of other existing software implementations of the VIA and is comparable to that of a hardware VIA implementation. The peak measured bandwidth for our system is 101.4MBytes/s and the one-way latency for short messages is 18.2μs.