Design And Implementation Of A System For Transparent Remote Memory Accessing

Along with the development of computer technology, the performance of CPUand system memory have been greatly improved which however, still cannot meetthe needs of the growing demand of memory of applications. As the I/O devicesrelatively lag behind, the performance of the disk now becomes the main bottleneckthat influences the overall performance of the computer.In order to improve LAN memory utilization ratio and system I/O performance,take advantage of the characteristics of high bandwidth and low latency forhigh-speed LAN’s transmission, in this paper, through expanding the capacity ofsystem exchange zone and improving its speed of page replacement, the I/Ointensive application of distributed system for transparent remote memoryaccessing—NS-DSM comes out on the basis of previous studies. The main work ofthis paper has the following several points.Firstly, this paper create a network block device to access and response accessoperations for remote memory, and then through radix tree to find, insert, deleteentries for mapping memory to remote memory in order to access the free memoryof other nodes in the client node.Secondly, NS-DSM system mounted network block device to the client nodethrough create and activate swap space for accessing remote memory transparentlyin application layer. In order to the memory page could transmit in the Ethernetwhich the maximum transmission unit is1500KB, the system implementedlightweight transport protocol-access network memory protocol to fragment andreassemble the memory page, and transmit for data packets.Thirdly, this paper puts forward the client-server conversion strategy. Thisstrategy of system of nodes are the role judgment and service switch makes eachnode load balance and guarantee the system to run in a "balanced" state.The strategy depending on system memory usage and load a different state,and detect the node’s free memory when the system is running on a regular basisand do the appropriate service conversion. So this strategy makes each node loadbalancing in the system as so as possible, so that the entire system is "balanced"state of a resource utilization.In the NS-DSM system, local area network of active sharing memory, and needn’t to be any modification of system kernel, any specific API and functionlibrary. It is completely transparent for application. Experiments show that, for alarge disk access and the application of the page exchange, the system caneffectively improve the performance and execution speed.