16225032
Autonomous Management of Clustered Server Systems Using JINI
A framework for the autonomous management of clustered server systems called LAMA (Large-scale system’s Autonomous Management Agent) is proposed in this paper. LAMA is based on agents, which are distributed over the nodes and built on JINI infrastructure. There are two classes of agents: a grand LAMA and ordinary LAMAs. An ordinary LAMA abstracts an individual node and performs node-wide configuration. The grand LAMA is responsible for monitoring and controlling all the ordinary ones. Using the discovery, join, lookup, and distributed security operations of JINI, a node can join the clustered system without secure administration. Also, a node’s failure can be detected automatically using the lease interface of the JINI. Resource reallocation is performed dynamically by a reallocation engine in the grand agent. The reallocation engine gathers the status of remote nodes, predicts resource demands, and executes reallocation by accessing the ordinary agents. The proposed framework is verified on our own clustered internet servers, called the CORE-Web server, for an audio-streaming service. The nodes are dynamically reallocated satisfying the performance requirements.
24658698
DNS: disk-to-network splicing for network driven data transferring
In Internet servers that run on general-purpose operating systems, network subsystems and disk subsystems cooperate with each other for user requests. Many studies have focused on optimizing the data movement across the subsystems to reduce data copying overhead among intermediate buffers such as process buffers, network send buffers and disk buffers. When data are moved across the subsystems, events such as read requests and write requests for data movement are also delivered across the subsystems by the servers and operating systems. However, there have been fewer studies on the optimization of event delivery which controls data copying timing across the subsystems. In conventional operating systems, to transfer data in the disk subsystem into the network subsystem, several different contexts are involved. A series of events are passed through the contexts. Whenever an event in one context is passed into the other context, context switching and scheduling are incurred. We have developed inter-subsystem event delivery mechanism, disk-to-network splicing (DNS), which optimizes event delivery among the subsystems involved to suppress scheduling and context switching during I/O request processing. We developed a DNS mechanism and performed experiments on Linux 2.4. The experimental results show that the system performance is improved by 4.9% 10.1%.
12908256
Improving Connection Management of the OpenLDAP Directory Server
This paper describes our effort to improve the performance of the connection management subsystem of the OpenLDAP directory server. Two proposed architectures, the multi-listener and the lightweight listener architectures, will be described and compared to each other. This paper will also describe our effort to improve the synchronization of multiple threads by introducing a semaphore based resource control scheme. The new connection management schemes proposed in this paper made the OpenLDAP directory server perform better in the presence of long latency operations and reduces the overhead caused by unnecessary context switching and inefficient event polling.
7239157
IPS-2: The Second Generation of a Parallel Program Measurement System
IPS, a performance measurement system for parallel and distributed programs, is currently running on its second implementation. IPS's model of parallel programs uses knowledge about the semantics of a program's structure to provide two important features. First, IPS provides a large amount of performance data about the execution of a parallel program, and this information is organized so that access to it is easy and intuitive. Secondly, IPS provides performance analysis techniques that help to guide the programmer automatically to the location of program bottlenecks. The first implementation of IPS was a testbed for the basic design concepts, providing experience with a hierarchical program and measurement model, interactive program analysis, and automatic guidance techniques. It was built on the Charlotte distributed operating system. The second implementation, IPS-2, extends the basic system with new instrumentation techniques, an interactive and graphical user interface, and new automatic guidance analysis techniques. This implementation runs on 4.3BSD UNIX systems, on the VAX, DECstation, Sun 4, and Sequent Symmetry multiprocessor. >
36007218
A Novel Geometric Algorithm for Fast Wire-Optimized Floorplanning