Re: Why choosing AF_XDP (busy polling) over DPDK

On Wed, Dec 14, 2022 at 9:16 AM Federico Parola
<[email protected]> wrote:
>
> Hello everyone,
> in a context in which all traffic is sent to user space, and the main
> concern is performance (so AF_XDP busy polling is the best candidate),
> is there a reason to choose AF_XDP instead of DPDK for packet I/O, given
> that the latter is still much faster?

The choice is not AF_XDP vs DPDK, since DPDK can run on top of AF_XDP.
The choice is do you want to use user-space drivers or kernel space
drivers. There are many pros and cons with both approaches. The two
main advantages of user-space drivers in DPDK are that they are faster
than their kernel counterparts and you get access to many NIC features
that are not available right now from user-space if you are using a
kernel driver. Kernel drivers, on the other hand, enables you to
deploy your application on any Linux system (from a certain version)
and does not force you into the strict execution model of DPDK (which
is what most people use with user-space drivers). Everything in Linux
is still usable and it is easy to have a system that mixes data-plane
processing with other types of workloads. If the only thing you care
about is max performance of a pure packet processing workload on a
system you have complete control over, the choice is easy: go with a
user-space driver and DPDK. If this is not your ultimate goal, then
XDP and AF_XDP might be something to consider.

There are likely some good write-ups on the Internet about this.

/Magnus

> Best regards,
> Federico Parola