Kernel bypass for UDP and TCP on Linux- what does it involve?

Question

Per http://www.solacesystems.com/blog/kernel-bypass-revving-up-linux-networking:

[...]a network driver called OpenOnload that use “kernel bypass” techniques to run the application and network driver together in user space and, well, bypass the kernel. This allows the application side of the connection to process many more messages per second with lower and more consistent latency.

[...]

If you’re a developer or architect who has fought with context switching for years kernel bypass may feel like cheating, but fortunately it’s completely within the rules.

What are the functions needed to do such kernel bypassing?

Answer 1

A TCP offload engine will "just work", no special application programming needed. It doesn't bypass the whole kernel, it just moves some of the TCP/IP stack from the kernel to the network card, so the driver is slightly higher level. The kernel API is the same.

TCP offload engine is supported by most modern gigabit interfaces.

Alternatively, if you mean "running code on a SolarFlare network adapter's embedded processor/FPGA 'Application Onload Engine'", then... that's card-specific. You're basically writing code for an embedded system, so you need to say which kind of card you're using.