From: Jakub Kicinski Date: Mon, 15 Jul 2024 03:32:41 +0000 (-0700) Subject: Merge branch 'virtio-net-support-af_xdp-zero-copy' X-Git-Tag: io_uring-6.11-20240722~71^2~19 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=d944c27a9d58179b2fd96e23104f213481ec1e8d;p=linux-2.6-block.git Merge branch 'virtio-net-support-af_xdp-zero-copy' Xuan Zhuo says: ==================== virtio-net: support AF_XDP zero copy v5: http://lore.kernel.org/all/20240611114147.31320-1-xuanzhuo@linux.alibaba.com XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero copy feature of xsk (XDP socket) needs to be supported by the driver. The performance of zero copy is very good. mlx5 and intel ixgbe already support this feature, This patch set allows virtio-net to support xsk's zerocopy xmit feature. At present, we have completed some preparation: 1. vq-reset (virtio spec and kernel code) 2. virtio-core premapped dma 3. virtio-net xdp refactor So it is time for Virtio-Net to complete the support for the XDP Socket Zerocopy. Virtio-net can not increase the queue num at will, so xsk shares the queue with kernel. On the other hand, Virtio-Net does not support generate interrupt from driver manually, so when we wakeup tx xmit, we used some tips. If the CPU run by TX NAPI last time is other CPUs, use IPI to wake up NAPI on the remote CPU. If it is also the local CPU, then we wake up napi directly. This patch set includes some refactor to the virtio-net to let that to support AF_XDP. Because there are too many commits, the work of virtio net supporting af-xdp is split to rx part and tx part. This patch set is for rx part. So the flag NETDEV_XDP_ACT_XSK_ZEROCOPY is not added, if someone want to test for af-xdp rx, the flag needs to be adding locally. ENV: Qemu with vhost-user(polling mode). Host CPU: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz testpmd> show port stats all ######################## NIC statistics for port 0 ######################## RX-packets: 19531092064 RX-missed: 0 RX-bytes: 1093741155584 RX-errors: 0 RX-nombuf: 0 TX-packets: 5959955552 TX-errors: 0 TX-bytes: 371030645664 Throughput (since last show) Rx-pps: 8861574 Rx-bps: 3969985208 Tx-pps: 8861493 Tx-bps: 3969962736 ############################################################################ testpmd> show port stats all ######################## NIC statistics for port 0 ######################## RX-packets: 68152727 RX-missed: 0 RX-bytes: 3816552712 RX-errors: 0 RX-nombuf: 0 TX-packets: 68114967 TX-errors: 33216 TX-bytes: 3814438152 Throughput (since last show) Rx-pps: 6333196 Rx-bps: 2837272088 Tx-pps: 6333227 Tx-bps: 2837285936 ############################################################################ But AF_XDP consumes more CPU for tx and rx napi(100% and 86%). ==================== Link: https://patch.msgid.link/20240708112537.96291-1-xuanzhuo@linux.alibaba.com Signed-off-by: Jakub Kicinski --- d944c27a9d58179b2fd96e23104f213481ec1e8d