Hi. I wanted to understand the PCIe usage while issuing Infiniband verbs. When posting a verb to a queue pair, how is the request descriptor written to the HCA? IMO, there are two options for this:
1. CPU prepares the descriptor in local memory. After preparing the descriptor, it writes the location of the descriptor to a hardwired register on the HCA (this process is called "ringing the doorbell"?). The HCA then reads the descriptor via DMA. 2. The CPU writes the entire descriptor to the HCA's memory via PCIe MMIO. Then, it rings the doorbell to alert the HCA. To me, the first one makes more sense, but I'm not sure. It would be great if someone could tell more about this. Thanks for your help. --Anuj -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
