This paper describes the micro-architecture of a Coherency Hub (CoHub) ASIC for a 4-socket highly-threaded multiprocessor using Sun's UltraSPARC ¯ T2 Plus processor. UltraSPARC T2 Plus is an 8-core ...CMT processor in the Sun Servers with CoolThreadsTM Technology family. CoHub enables cost-effective scaling to 4 nodes with a total thread count of 256 and near-linear performance scaling on transaction processing workloads. Extending a 2-node "glueless" system to a 4-node system without processor changes was a key requirement. CoHub broadcasts snoop requests, serializes requests to the same address, and consolidates snoop responses. It communicates with nodes via serial links, using a proprietary link layer implemented over FBDIMM. We present the coherency scheme, ASIC design, transaction flows, and engineering challenges created by 800 MHz operation and 6-stage pipeline budget. We report performance scalability results measured on commercial server benchmarks.
Cloud computing has gained huge attention over the past decades because of continuously increasing demands. There are several advantages to organizations moving toward cloud-based data storage ...solutions. These include simplified IT infrastructure and management, remote access from effectively anywhere in the world with a stable Internet connection and the cost efficiencies that cloud computing can bring. The associated security and privacy challenges in cloud require further exploration. Researchers from academia, industry, and standards organizations have provided potential solutions to these challenges in the previously published studies. The narrative review presented in this survey provides cloud security issues and requirements, identified threats, and known vulnerabilities. In fact, this work aims to analyze the different components of cloud computing as well as present security and privacy problems that these systems face. Moreover, this work presents new classification of recent security solutions that exist in this area. Additionally, this survey introduced various types of security threats which are threatening cloud computing services and also discussed open issues and propose future directions. This paper will focus and explore a detailed knowledge about the security challenges that are faced by cloud entities such as cloud service provider, the data owner, and cloud user.
In this paper, a novel population-based technique called dung beetle optimizer (DBO) algorithm is presented, which is inspired by the ball-rolling, dancing, foraging, stealing, and reproduction ...behaviors of dung beetles. The newly proposed DBO algorithm takes into account both the global exploration and the local exploitation, thereby having the characteristics of the fast convergence rate and the satisfactory solution accuracy. A series of well-known mathematical test functions (including both 23 benchmark functions and 29 CEC-BC-2017 test functions) are employed to evaluate the search capability of the DBO algorithm. From the simulation results, it is observed that the DBO algorithm presents substantially competitive performance with the state-of-the-art optimization approaches in terms of the convergence rate, solution accuracy, and stability. In addition, the Wilcoxon signed-rank test and the Friedman test are used to evaluate the experimental results of the algorithms, which proves the superiority of the DBO algorithm against other currently popular optimization techniques. In order to further illustrate the practical application potential, the DBO algorithm is successfully applied in three engineering design problems. The experimental results demonstrate that the proposed DBO algorithm can effectively deal with real-world application problems.
