Enhancing Applications Performance on Intel Paragon through Dynamic Memory Allocation

摘要

The Paragon operating system (OS) is based upon OSF/1 AD, the first standard compliant, distributed operating system for massively parallel processing system. The OSF addresses several major problems and supports virtual memory (VM). The OS manages the VM by performing two services, among others. Firstly, paging-in service is performed by paging-in the executable code from service node to the compute node. This includes the paging-in of empty data corresponding to static allocation of arrays not at the DIMENSION statement but at the first reference and use of the arrays. Secondly, paging-out service is performed by paging-out the unused part of the OSF server to boot node to make space available for the user's executable code. These paging-in and paging-out activities take place simultaneously and drastically degrade the performance of the user code. We have investigated this problem systematically and in detail, and found that the dynamic allocation of memory completely eliminates the unnecessary and undesirable service of paging-in of the empty data arrays from the service node to the compute node and thereby increases, in some cases, the performance of applications by 30 to 40.