Once you have configured the common network path and SPRAY has been installed on all client PCs, everything is ready for distributed computing with SPRAY. The performance of the network depends on the speed of the individual computers and the size of the tasks. The following remarks can be used as a guideline for your own network experiments.

In addition to the numerical work to be performed for the ray-tracing the processing of the tasks requires some extra time. The creation of the tasks on the master PC, the search for tasks on the client PCs and the exchange of configuration files and results cause a delay of a few seconds for every task. If a local computation on the master PC takes 10 seconds, and you split it up into 50 tasks to be processed in the network, it can easily take several minutes until you get the final result. Distributed computing is faster than local computing only if you have large simulation jobs and not too many tasks.

On the other hand, the number of tasks should not be too small. If you employ various computers which may differ in speed you should try to keep them all busy. If the individual tasks are too large the slow PCs will probably never give a useful contribution: While a slow PC is working on a too heavy computational load, the faster PCs may run out of work and start to work on the pending task of the slow PC as well, eventually overtaking it.

Current limitations in distributed computing: