In the Function-Offload Model, the SPEs are used as accelerators for performance-critical procedures.
This model is the quickest way to effectively use the Cell Broadband Engine with an existing application. In this model, the main application runs on the PPE and calls selected procedures to run on one or more SPEs.
The Function-Offload Model is sometimes called the Remote Procedure Call (RPC) Model. The model allows a PPE program to call a procedure located on an SPE as if it were calling a local procedure on the PPE. This provides an easy way for programmers to use the asynchronous parallelism of the SPEs without having to understand the low-level workings of the MFC DMA layer.
In this model, you identify which procedures should execute on the PPE and which should execute on the SPEs. The PPE and SPE source modules must be compiled separately, by different compilers.