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Xdp or dpdk

Иван Иванов
 

Hi. I need you advice. I have to write app to filter and LB ethernet traffic from 100G to 10x10G. What is better to use? eBPF XDP or DPDK?

Jesper Dangaard Brouer
 

On Thu, 20 Sep 2018 16:02:37 +0300 Иван Иванов <iwan12iwan12@...> wrote:
Hi. I need you advice.
I have to write app to filter and LB ethernet traffic from 100G to
10x10G. What is better to use? eBPF XDP or DPDK?
Interesting use-case of Load-Balancing 100G to 10x 10G.

I would obviously choose XDP, but I'm biased ;-)

I want to stress, that you have to handle, in _your_ BPF prog, how to
load-balance and handle _when_ the overload/overrun problem occurs. As
you have faster link feeds into slower links, you can overload those
links.

With XDP/BPF you should attach to the BPF tracepoint xdp_devmap_xmit,
which allows you to detect the TX overrun happens (see sample code [1]
and [2]). And then you need to communicate this info via a BPF-map, to
your Load-Balance decision XDP-prog, so it can take action.

With this tracepoint approach packets will get lost, before an event
happens. I am considering extending XDP to have another XDP-hook, at
XDP_REDIRECT transition to TX point, which would allow you to re-do a
load-balance decision, then a device TX-queue is full. But we need a
good use-case, before adding such infra-structure (maybe your
use-case?). This is something Toke and I will be taking about here:
[3] http://vger.kernel.org/lpc-networking.html#session-19


Sample code#1:
[1] https://github.com/torvalds/linux/blob/master/samples/bpf/xdp_monitor_kern.c#L213-L258

Sample code#2:
[2] https://github.com/torvalds/linux/blob/master/samples/bpf/xdp_redirect_cpu_kern.c#L572-L625

--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer