A low-power voltage-mode-logic(VML) transmitter fabricated in TSMC 28 nm CMOS technology is presented.The VML driver outputs a high-swing signal and consumes less power than a current-mode-logic (CML) driver.To further reduce power,the driver is divided into two voltage domains by level shifters.Moreover, the proposed driver topology can achieve mutually decoupled impedance self-calibration and equalization control. The measurement result shows that the transmitter merely dissipates 23 mW/channel while exhibiting an 880 mV differential eye height at 4.488 Gb/s.
Workload consolidation is a common method to improve the resource utilization in clusters or data centers. In order to achieve efficient workload consolidation, the runtime characteristics of a program should be taken into con-sideration in scheduling. In this paper, we propose a novel index system for efficiently describing the program runtime characteristics. With the help of this index system, programs can be classified by the following runtime characteristics: 1) dependence to multi-dimensional resources including CPU, disk I/O, memory and network I/O;and 2) impact and vulnerability to resource sharing embodied by resource usage and resource sensitivity. In order to verify the effectiveness of this novel index system in workload consolidation, a scheduling strategy, Sche-index, using the new index system for workload consolidation is proposed. Experiment results show that compared with traditional least-loaded scheduling strategy, Sche-index can improve both program performance and system resource utilization significantly.
Lin WANGDepei QIANRui WANGZhongzhi LUANHailong YANGHuaxiang ZHANG
软件定义网络(software defined network,简称SDN)通过集中式的控制器提高了网络的可编程性,成为近年来网络领域非常热门的话题.以Openflow网络为代表的软件定义网络将逻辑控制与数据转发相隔离,为网络虚拟化技术提供了良好的平台.集中式的抽象与控制使得SDN虚拟化框架的处理效率成为主要瓶颈.现有的SDN虚拟化框架由于缺乏对细粒度并行的支持,为编程人员充分利用多核/众核资源、控制更大规模的网络带来了极大的挑战.为了提高SDN虚拟化框架的处理效率,提出一种新的SDN虚拟化编程框架,通过新颖的API和运行时,在框架内部支持细粒度的并行处理.该框架通过对网络中流和网络资源进行抽象,使开发人员可以直接通过划分流空间来定义不同的虚拟网络,利用无锁的编程方式对共享的网络资源和流进行操作.实验结果表明,该框架在逻辑控制的执行效率方面具有良好的可扩展性,可以创建出更大规模的虚拟网络,并对其进行更为复杂的控制.
