Performance and evaluation of real-time multicomputer control systems

Three experiments on fault tolerant multiprocessors (FTMP) were begun. They are: (1) measurement of fault latency in FTMP; (2) validation and analysis of FTMP synchronization protocols; and investigation of error propagation in FTMP

Shared versus distributed memory multiprocessors

The question of whether multiprocessors should have shared or distributed memory has attracted a great deal of attention. Some researchers argue strongly for building distributed memory machines, while others argue just as strongly for programming shared memory multiprocessors. A great deal of research is underway on both types of parallel systems. Special emphasis is placed on systems with a very large number of processors for computation intensive tasks and considers research and implementation trends. It appears that the two types of systems will likely converge to a common form for large scale multiprocessors

MPF: A portable message passing facility for shared memory multiprocessors

The design, implementation, and performance evaluation of a message passing facility (MPF) for shared memory multiprocessors are presented. The MPF is based on a message passing model conceptually similar to conversations. Participants (parallel processors) can enter or leave a conversation at any time. The message passing primitives for this model are implemented as a portable library of C function calls. The MPF is currently operational on a Sequent Balance 21000, and several parallel applications were developed and tested. Several simple benchmark programs are presented to establish interprocess communication performance for common patterns of interprocess communication. Finally, performance figures are presented for two parallel applications, linear systems solution, and iterative solution of partial differential equations

Reduction of Context Switches due to Task Synchronization in Uniprocessor and Multiprocessor Platform

The problem of frequent context switches in multitasking is a real scheduling overhead which wastes extra CPU cycles, memory and causes much delay in scheduling. This paper focuses on reducing the context switches that result due to blocking when jobs are required to synchronize. The Priority Ceiling Protocol (PCP) is used to synchronize the tasks in uniprocessor as well as multiprocessor platforms. The jobs are scheduled using Earliest Deadline First (EDF) policy. The simulation results show that the context switches are reduced by about 20% on an average using our technique of avoiding context switches due to blocking

An implementation of the flexible spin-lock model in ERIKA Enterprise on a multi-core platform

Recently, the flexible spin-lock model (FSLM) has been introduced, unifying spin-based and suspension-based resource sharing protocols for real-time multiprocessor platforms by explicitly identifying the spin-lock priority as a parameter.Earlier work focused on the definition of a protocol for FSLM and its corresponding analysis under the assumption that various types of implementation overhead could be ignored.In this paper, we briefly describe an implementation of the FSLM for a selected range of spin-lock priorities in the ERIKA Enterprise RTOS as instantiated on an Altera Nios II platform using 4 soft-core processors. Moreover, we present measurement results for the protocol specific overhead of FSLM as well as thenatively provided multiprocessor stack resource policy (MSRP).Given these results, we are now in a position to judge when it is advantageous to use either MSRP or FMLP for our system set-up for given global resource access times of tasks

An implementation of the flexible spin-lock model in ERIKA Enterprise on a multi-core platform

Recently, the flexible spin-lock model (FSLM) has been introduced, unifying spin-based and suspension-based resource sharing protocols for real-time multiprocessor platforms by explicitly identifying the spin-lock priority as a parameter.Earlier work focused on the definition of a protocol for FSLM and its corresponding analysis under the assumption that various types of implementation overhead could be ignored.In this paper, we briefly describe an implementation of the FSLM for a selected range of spin-lock priorities in the ERIKA Enterprise RTOS as instantiated on an Altera Nios II platform using 4 soft-core processors. Moreover, we present measurement results for the protocol specific overhead of FSLM as well as thenatively provided multiprocessor stack resource policy (MSRP).Given these results, we are now in a position to judge when it is advantageous to use either MSRP or FMLP for our system set-up for given global resource access times of tasks

The Impact of Parallel Processing on Operating Systems

The base entity in computer programming is the process or task. The parallelism can be achieved by executing multiple processes on different processors. Distributed systems are managed by distributed operating systems that represent the extension for multiprocessor architectures of multitasking and multiprogramming operating systems.