Traffic shaping at 10~300mbps at a 10Gbps link

Hi.

I'm having trouble to shape traffic for a few thousand users.
Every time the interface bandwidth reaches around 4~4.5gbps, CPU load goes from 10~20% to 90~100% when using HTB. For HFSC this occurs around 2gbps.

I googled the problem and bumped into this topic (xdp-project) and Mr. Brouer told me about this list.

Please tell me which info I can feed you to help me with this issue.
I made a lots of experiences with no luck.

I am not a top level expert but I learn quick.

Regards

Ethy