“zero copy networking” vs “kernel bypass”?

Question

What is the difference between \"zero-copy networking\" and \"kernel bypass\"? Are they two phrases meaning the same thing, or different? Is kernel bypass a technique used w

Answer 1

Other examples of kernel bypass and zero copy are DPDK and RDMA. When an application uses DPDK it is bypassing the kernel TCP/IP stack. The application is creating the Ethernet frames and the NIC grabbing those frames with DMA directly from user space memory so it's zero copy because there is no copy from user space to kernel space. Applications can do similar things with RDMA. The application writes to queue pairs that the NIC directly access and transmits. RDMA iblibverbs is used inside the kernel as well so when iSER is using RDMA it's not Kernel bypass but it is zero copy.

http://dpdk.org/

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