On 4/16/21 2:16 AM, Xuan Zhuo wrote: > In page_to_skb(), if we have enough tailroom to save skb_shared_info, we > can use build_skb to create skb directly. No need to alloc for > additional space. And it can save a 'frags slot', which is very friendly > to GRO. > > Here, if the payload of the received package is too small (less than > GOOD_COPY_LEN), we still choose to copy it directly to the space got by > napi_alloc_skb. So we can reuse these pages. > > Testing Machine: > The four queues of the network card are bound to the cpu1. > > Test command: > for ((i=0;i<5;++i)); do sockperf tp --ip 192.168.122.64 -m 1000 -t 150& > done > > The size of the udp package is 1000, so in the case of this patch, there > will always be enough tailroom to use build_skb. The sent udp packet > will be discarded because there is no port to receive it. The irqsoftd > of the machine is 100%, we observe the received quantity displayed by > sar -n DEV 1: > > no build_skb: 956864.00 rxpck/s > build_skb: 1158465.00 rxpck/s >
virtio_net is using napi_consume_skb, so napi_build_skb should show a small increase from build_skb. _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
