It is desirable in a distributed system to have the system load balanced evenly among the nodes so that the mean job response time is minimized. In this paper, we present.a dynamic load balancing mechanism (DLB). It a...It is desirable in a distributed system to have the system load balanced evenly among the nodes so that the mean job response time is minimized. In this paper, we present.a dynamic load balancing mechanism (DLB). It adopts a centralized approach and is network topology independent. The DLB mechanism employs a set of thresholds which are automatically adjusted as the system load changes. lt also provides a simple mechanism for the system to switch between periodic and instantaneous load balancing policies with ease. The performance of the proposed algorithm is evaluated by intensive simulations for various parameters. The simulAtion results show that the mean job response time in a system implementing DLB algorithm is significantly lower than the same system without load balancings. Furthermore, compared with a previously proposed algorithm, DLB algorithm demonstrates improved performance, especially when the system is heavily loaded and the load is unevenly distributed.展开更多
In the upgrade project of Hefei Light Source（HLSⅡ）,a new digital longitudinal bunch-by-bunch feedback system will be developed to suppress the coupled bunch instabilities in the storage ring effectively.We design a...In the upgrade project of Hefei Light Source（HLSⅡ）,a new digital longitudinal bunch-by-bunch feedback system will be developed to suppress the coupled bunch instabilities in the storage ring effectively.We design a new waveguide overloaded cavity longitudinal feedback kicker as the feedback actuator.The beam pipe of the kicker is a racetrack shape so as to avoid a transition part to the octagonal vacuum chamber.The central frequency and the bandwidth of the kicker have been simulated and optimized to achieve design goals by the HFSS code.A higher shunt impedance can be obtained by using a nose cone to reduce the feedback power requirement.Before the kicker cavity was installed in the storage ring,a variety of measurements were carried out to check its performance.All these results of simulation and measurement are presented.展开更多
文摘It is desirable in a distributed system to have the system load balanced evenly among the nodes so that the mean job response time is minimized. In this paper, we present.a dynamic load balancing mechanism (DLB). It adopts a centralized approach and is network topology independent. The DLB mechanism employs a set of thresholds which are automatically adjusted as the system load changes. lt also provides a simple mechanism for the system to switch between periodic and instantaneous load balancing policies with ease. The performance of the proposed algorithm is evaluated by intensive simulations for various parameters. The simulAtion results show that the mean job response time in a system implementing DLB algorithm is significantly lower than the same system without load balancings. Furthermore, compared with a previously proposed algorithm, DLB algorithm demonstrates improved performance, especially when the system is heavily loaded and the load is unevenly distributed.
基金Supported by Natural Science Foundation of China(11175173,11005105)
文摘In the upgrade project of Hefei Light Source（HLSⅡ）,a new digital longitudinal bunch-by-bunch feedback system will be developed to suppress the coupled bunch instabilities in the storage ring effectively.We design a new waveguide overloaded cavity longitudinal feedback kicker as the feedback actuator.The beam pipe of the kicker is a racetrack shape so as to avoid a transition part to the octagonal vacuum chamber.The central frequency and the bandwidth of the kicker have been simulated and optimized to achieve design goals by the HFSS code.A higher shunt impedance can be obtained by using a nose cone to reduce the feedback power requirement.Before the kicker cavity was installed in the storage ring,a variety of measurements were carried out to check its performance.All these results of simulation and measurement are presented.
