Load balancing has been a topic of interest in both academia and industry, mainly because of the scope for performance enhancement that is available to be exploited in many parallel and distributed processing environments. Among the many approaches that have been used to solve the load balancing problem, we find that only very few use prediction of code execution times. Our reasoning for this is that the field of code prediction is in its infancy. As of this writing, we are not aware of any prediction-based load balancing approach that uses prediction8 of code-execution times, and uses neither the information provided by the user, nor an off-line step that does the prediction, the results of which are then used at run-time. In this context, it is important to note that prior studies have indicated the feasibility of predicting the CPU requirements of general application programs. Our motivation in using prediction-based load balancing is to determine the feasibility of the approach. The reasoning behind that is the following: if prediction-based load balancing does yield good performance, then it may be worthwhile to develop a predictor that can give a rough estimate of the length of the next CPU burst of each process. While high accuracy of the predictor is not essential, the computation overhead of the predictor must be sufficiently' small, so as not to offset the gain of load balancing. As for the system, we assume a set of autonomous computers, that are connected by a fast, shared medium. The individual nodes can vary in the additional hardware and software that may be available in them. Further, we assume that the processes in the workload are sequential. The first step is to fix the parameters for our assumed predictor. Then, an algorithm that takes into account the characteristics of the predictor is proposed. There are many trade-off decisions in the design of the algorithm, including certain steps in which we have relied on trial and error method to find suitable values. The next logical step is to verify the efficiency of the algorithm. To assess its performance, we carry out event driven simulation. We also evaluate the robustness of the algorithm with respect to the characteristics of the predictor. The contribution of the thesis is as follows: It proposes a load-balancing algorithm for a heterogeneous cluster of workstations connected by a fast network. The simulation assumes that the heterogeneity is limited to variability in processor clock rates; but the algorithm can be applied when the nodes have other types of heterogeneity as well. The algorithm uses prediction of CPU burst lengths as its basic input unit. The performance of the algorithm is evaluated through event driven simulation using assumed workload distributions. The results of the simulation show that the algorithm yields a good improvement in response times over the scenario in which no load redistribution is done.

This thesis is part of the European MANY project. The goal of MANY is to provide developers with tools to develop software for multi and many-core hardware platforms. This is the first thesis that is part of MANY at Enea. The thesis aims to provide a knowledge base about software on many-core at the Enea student research group. More than just providing a knowledge base, a part of the thesis is also to port Enea's operating system OSE to Tilera's many-core processor TILEpro64. The thesis shall also investigate the memory hierarchy and interconnection network of the Tilera processor. The knowledge base about software on many-core was constrained to investigating the shared memory model and operating systems for many-core. This was achieved by investigating prominent academic research about operating systems for many-core processors. The conclusion was that a shared memory model does not scale and for the operating system case, operating systems shall be designed with scalability as one of the most important requirements. This thesis has implemented the hardware abstraction layer required to execute a single-core version of OSE on the TILEpro architecture. This was done in three steps. The Tilera hardware and the OSE software platform were investigated. After that, an OSE target port was chosen as reference architecture. Finally, the hardware dependent parts of the reference software were modified. A foundation has been made for future development.

No description available.

The Spider Project is an object-oriented distributed system which provides a testbed for researchers in the Department of Computer Science, CSUSB, to conduct research on distributed systems.

Spider II system is the second version implementation of the Spider project. This system is the first distributed computation research project in the Department of Computer Science at CSUSB. Spider II is a distributed virtual machine on top of the UNIX or LINUX operating system. Spider II features multi-tasking, load balancing and fault tolerance, which optimize the performance and stability of the system.

The future of computing lies with distributed systems, i.e. a network of workstations controlled by a modern distributed operating system. By supporting load balancing and parallel execution, the overall performance of a distributed system can be improved dramatically. Process migration, the act of moving a running process from a highly loaded machine to a lightly loaded machine, could be used to support load balancing, parallel execution, reliability etc. This thesis identifies the problems past process migration facilities have had and determines the possible differing strategies that can be used to resolve these problems. The result of this analysis has led to a new design philosophy. This philosophy requires the design of a process migration facility and the design of an operating system to be conducted in parallel. Modern distributed operating systems follow the microkernel and client/server paradigms. Applying these design paradigms, in conjunction with the requirements of both process migration and a distributed operating system, results in a system where each resource is controlled by a separate server process. However, a process is a complex resource composed of simple resources such as data structures, an address space and communication state. For this reason, a process migration facility does not directly migrate the resources of a process. Instead, it requests the appropriate servers to transfer the resources. This novel solution yields a modular, high performance facility that is easy to create, debug and maintain. Furthermore, the design easily incorporates providing multiple migration strategies. In order to verify the validity of this design, a process migration facility was developed and tested within RHODOS (ResearcH Oriented Distributed Operating System). RHODOS is a modern microkernel and client/server based distributed operating system. In RHODOS, a process is composed of at least three separate resources: process state - maintained by a process manager, address space - maintained by a memory manager and communication state - maintained by an InterProcess Communication Manager (IPCM). The RHODOS multiple strategy migration manager utilises the services of the process, memory and IPC Managers to migrate the resources of a process. Performance testing of this facility indicates that this design is as fast or better than existing systems which use faster hardware. Furthermore, by studying the results of the performance test ing, the conditions under which a particular strategy should be employed have been identified. This thesis also addresses heterogeneous process migration. The current trend is to have islands of homogeneous workstations amid a sea of heterogeneity. From this situation and the current literature on the topic, heterogeneous process migration can be seen as too inefficient for general use. Instead, only homogeneous workstations should be used for process migration. This implies a need to locate homogeneous workstations. Entities called traders, which store and disseminate knowledge about the resources of several workstations, should be used to provide resource discovery. Resource discovery will enable the detection of homogeneous workstations to which processes can be migrated.

This project implements a real application on the Spider II, which is a simulation of Soil Water Movement Model. The main objectives of this project were to develop a parallel and distributed algorithm for the Soil Water Model; implement the Soil Water Movement Simulation model on the Spider II distributed system and to evaluate the performance of simulating the Soil Water Movement Model on Spider II.