Hi,I am running the txonly microbenchmark from the AF_XDP-example sample program in bpf-examples. Howerver, I noticed strange performance with different tx packet sizes.
With the following command I generate the below results: ./xdpsock -i enp2s0np0 -q 4 -t -b 2048 -m -s 128 -m Driver: mlx5 on 40Gbps ConnectX-6 Kernel version: 6.0.0-rc6+ | Pkt Size | Native-ZC PPS | Native-C PPS | Generic PPS || ----------- | -------------------- | ------------------ | ----------------- |
| 64 | 16.5M | 1.73M | 1.71M | | 128 | 9.42M | 1.72M | 1.66M | | 256 | 7.78M | 1.64M | 1.66M | | 512 | 9.39M | 1.62M | 1.59M | | 1024 | 4.78M | 1.42M | 1.38M |At size 128B, I expect 16.5M packets (the limiting performance of AF_XDP) since the link is not saturated. The problem is more obvious at size 256B, only 7.78B even though it jumps again to 9.39M at 512. So I think the problem is related to the packet size and not to a limited performance in the xsk engine in the kernel.
Or what do you think? I have already opened an issue on github here: https://github.com/xdp-project/bpf-examples/issues/61 Best, Jalal
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