Abstract
In this work, we present an OpenMP implementation suitable for multiprogrammed environments on Intel-based SMP systems. This implementation consists of a runtime system and a resource manager, while we use the NanosCompiler to transform OpenMP-coded applications into code with calls to our runtime system. The resource manager acts as the operating system scheduler for the applications built with our runtime system. It executes a custom made scheduling policy to distribute the available physical processors to the active applications. The runtime system cooperates with the resource manager in order to adapt each application's generated parallelism to the number of processors allocated to it, according to the resource manager scheduling policy. We use the OpenMP version of the NAS Parallel Benchmark suite in order to evaluate the performance of our implementation. In our experiments we compare the performance of our implementation with that of a commercial OpenMP implementation. The comparison proves that our approach performs better both on a dedicated and on a heavily multiprogrammed environment.