Docker swarm overlay and heavy softirq load?

Question

Docker

Hello.
I continue to deploy the service of one website in the docker cluster. I am currently facing a problem. That the load on the processor in the form of softirq has grown to 40%. I'm testing with nginx. The network is loaded on 200 megabits approximately. Roughly nginx hangs on a separate piece of iron, then after it, php is already running on other pieces of iron. Well, is this state of affairs normal and what to do if the network load doubles? How is it possible to scatter this at least over the processors?
Normal nginx without docker created a load 3 times less ... So there is enough iron power there and it’s not scary if a couple of cores go to network processing ...