The Study And Implementation Of User Space Driver And Environment Abstraction Layer Based On Intel DPDK Framework

In the past several years, Software Defined Network (SDN) and Network Function Virtualization (NFV) have become the most famous star in the network world. Though they don’t have the same background and application, they both need a great deal of forwarding table item when used in the specific situation. Then, it is improper to storage and process the large number of forwarding table only in the hardware. Meanwhile the continuous improvement of the network speed has raised higher requirements for the time delay of the network devices.In response to these circumstances, we come up with a data processing scheme using the hardware extract the data and the software process the data.It combines both software and hardware advantages. From the bottom to the top, it contains three parts on the whole: FPGA logic development hardware part, low time consumption data transmission software part, data processing software part. A highlight of this processing scheme is that most data passed between the FPGA logic development hardware part and the data processing software part is not a complete packet, but some key data of the packet. The benefit of this is that it can save the bandwidth of RAM and PCI-E.Different from using hardware realize lookup, using software realize lookup will experience more complex process and take more time, In order to apply this data processing scheme to the high-speed network, when designing the software, we should make every effort to decrease the time consumption during the receiving, sending and processing. The main work of this paper is designing and realizing the low time consumption data transmission software part, specifically concludes three parts: Firstly, compares the differences between the traditional Linux device driver and the user space I/O, then designs an non-copy, non-interrupt, polling user space driver for the specific FPGA of our laboratory, which can bypass the Linux kernel and greatly decrease the time consumption during the receiving and sending process; Secondly, refers to the DPDK framework, and realizes an environment abstraction layer. The environment abstraction layer is responsible for gaining access to low-level resources such as hardware and memory space, it provides a low consumption and compact environment for the upper libraries and applications; Lastly, realizes a data processing software in charge of the forwarding function and jointly debugs, tests with the FPGA logic development hardware part. The test content includes the time delay of low time consumption data transmission software part and throughput rate of this scheme. Simultaneously, for the purpose of testing and comparing, realizes a simple NIC driver.