cpu performance drop between 4.18 and 5.10 kernel?

[mengkanglai]

Dear maintainers:
I updated my VM kernel from 4.18 to 5.10, and found that the CPU SI usage was higher under the 5.10 kernel for the same udp service.
I captured the flame graph and compared the two versions of kernels. 
Kernel 5.10 compared to 4.18 napi_complete_done function added gro_normal_list call (ommit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORMAL
skbs") Introduced), I removed gro_normal_list from napi_complete_done in 5.10 kernel, CPU SI usages was same as 4.18.
I don't know much about GRO, so I'm not sure if it can be modified in this way, and the consequences of such a modification?