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Small I/O requests are important for a large number of modern workloads in the data center. Traditionally, storage systems have been able to achieve low I/O rates for small I/O operations because of hard disk drive (HDD) limitations that are capable of about 100–150 IOPS (I/O operations per second) per spindle. Therefore, the host CPU processing capacity and network link throughput have been relatively...
The use of real-time operating systems for small micro controllers creates two major problems. The former refers to the way interruptions must be handled so that deadlines can be complied with. The latter regards the fact that there may be tasks that will not synchronize with events generated by multiple objects such as semaphores, mutexes, messages or interrupts. The present article discusses several...
While most microkernel-based systems implement non-essential software components as user space tasks and strictly separate those tasks during runtime, they often rely on a static configuration and composition of their software components to ensure safety and security. In this paper, we extend a microkernel-based system architecture with a Trusted Platform Module (TPM) and propose a verification mechanism...
Achieving high I/O throughput on modern servers presents significant challenges. With increasing core counts, server memory architectures become less uniform, both in terms of latency as well as bandwidth. In particular, the bandwidth of the interconnect among NUMA nodes is limited compared to local memory bandwidth. Moreover, interconnect congestion and contention introduce additional latency on...
In this paper, we present CLUE, a system event analytics tool for black-box performance diagnosis in production Cloud Computing systems. CLUE provides an unified and extensible means of profiling service transactional behaviors, and builds structured data called event sketches. CLUE further offers a set of analytic tools for summarizing and analyzing event sketches by integrating data mining and statistical...
RADIUS Accounting Server is used for receiving an accounting request and returning a response to a client. When the client is configured to use RADIUS Accounting, it will generate accounting requests towards accounting server. In case of accounting server not responding or dead, client keeps on archiving the requests until certain point. Once the server becomes active, client will flush all the archived...
RADIUS Accounting Server is used for receiving an accounting request and returning a response to a client. When the client is configured to use RADIUS Accounting, it will generate accounting requests towards accounting server. In a system where there are multiple servers configured in round-robin fashion, if some of the servers go down, it takes more time to reach the actual active server after retransmissions...
Interrupt virtualization remains a key overhead source in high performance network virtualization (Single-root I/O virtualization or SR-IOV). SR-IOV can give close to line rate network bandwidth and good scalability in the 10 Gbps network environment, however the overhead of the interrupt virtualization in SR-IOV remains non-trivial, due to additional trap-and emulation overhead on the virtual interrupt...
This paper describes a low-overhead and prolonged Linux process logging mechanism that is separated into networks for embedded systems with small memory. It is useful to log the behavior of Linux processes in Android in order to debug, test, and learn about the embedded systems. However, the logging system interferes with process scheduling and requires huge storage to capture the process behavior...
This paper presents OpenCL Remote framework that extends the native OpenCL platform model to network scale and utilizes the native OpenCL's support of heterogeneous computing. OpenCL Remote boosts performance by distributing computation over network to many compute devices in parallel.
Modern computer systems are becoming increasingly heterogeneous by comprising multi-core CPUs, GPUs, and other accelerators. Current programming approaches for such systems usually require the application developer to use a combination of several programming models (e.g., MPI with OpenCL or CUDA) in order to exploit the full compute capability of a system. In this paper, we presentd OpenCL (Distributed...
This paper deals with the observer problem for dynamical systems in a behavioral context. We are given a dynamical system together with a partition of the system variables into a set of known or measured variables and a set of unknown, to be estimated variables. The observer problem is to find a system that produces an estimate of the unknown variables on the basis of the known or measured variables...
Enterprises use design best practices to build applications that leverage the linear scalability of the cloud. These include methods like data sharding, application sharding, denormalized data stores, thin binary images etc. The design practices itself involve reengineering an application to the cloud. Enterprises view reengineering activities as a business risk and a costly affair. As Service oriented...
The philosophy upon which the Internet was built places the intelligence close to the edge. As the Internet has matured, intermediate devices or middleboxes, such as firewalls or application gateways, have been introduced, thereby weakening the end-to-end nature of the network. As a result, applications must often modify their behavior to accommodate the middleboxes. This is is especially true in...
In the literature, the notion of Race Condition deals with the interference between two processes A and B carrying out three interactions involving a shared object. The second interaction of the concurrent process B interleaves with the first and the third interactions of process A. Preventing Race Conditions attacks between concurrent processes is still an open problem. Many limitations remain such...
In this work we examine how transparent compression in the I/O path can improve space efficiency for online storage. We extend the block layer with the ability to compress and decompress data as they flow between the file-system and the disk. Achieving transparent compression requires extensive metadata management for dealing with variable block sizes, dynamic block mapping, block allocation, explicit...
The virtualization technology has been developed rapidly with the growth of the hardware supported virtualization technologies and the appearance of the various services. Many researchers are concentrating on developing the virtualization technologies which are recognized as the most significant core technology of the IT applications such as green IT and cloud computing. The major processor companies...
In this paper, the network security and traditional firewall technology were introduced, pointing out that the problems faced by traditional firewall. Then the structure of the distributed firewall, key technology and advantages of an in-depth study. The various parts of the text on the design and implementation of a detailed introduction. Then, the analysis of the control of several now distributed...
Along with the development and application of the high speed network, in order to reduce the cost of data copy and context switch, the paper presents an improved method of zero-copy data transmission that is suitable for the high speed network environment on Linux and UNIX platforms. The method can reduce the number of data copy and context switch between kernel and user mode. It is tested by transmitting...
Access control in SELinux is designed for a monolithic operating system. In order to apply SELinux in distributed environments it is necessary to extend the policy specification language to include the notion of location. This paper presents a system that translates a location extended policy to local-policies. A policy server does this translation and distributes local policies to the corresponding...
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