The SPU
The programs running on the SPU are handled in a slightly different way. On other architectures, a share group contains only processes. On the Cell, TotalView places SPU threads running the same executable into separate share groups. That is, on SPUs, a share group contains threads, not processes. SPU share groups can contain SPU threads running on other Cells, and these Cells can be within the same blade or within blades in a cluster.