HPL performance hints
In general, the performance of the depends on the underlying hardware resources: CPU, memory, disks, tapes, controllers, and so on. Any of these resources could be a bottleneck, depending on the speed of the resource, the load on the resource, and the particular nature of the load or unload.
For example, load and unload jobs that perform no conversions consume minimal CPU resources. These jobs are thus likely to be limited by device or controller bandwidth. Alternatively, ASCII loads and unloads are CPU intensive because of the overhead of conversion to and from ASCII. This section discusses some topics that you should consider when you try to improve performance.