I’m looking to get a multi GPU server for 8 GPU’s, mainly for testing & learning. As I understand most GPU servers use PEX chips as PCIe switches. I’m only starting to learn about how software like Tensorflow utilises the hardware, hence my following questions;
When doing p2p communication on GPU’s that are connected to a single chip (eg. PEX8796), is the DMA engine on the PEX chips used at all? Or is that kind of traffic handled by the GPU’s DMA engine?
Is the DMA engine on the chip needed to enable GPUDirect RDMA?