On Thu, Jan 17, 2019 at 08:08:53PM -0500, Willem de Bruijn wrote:
> From: Willem de Bruijn <[email protected]>
>
> On multiqueue network devices, RPS maps are configured independently
> for each receive queue through /sys/class/net/$DEV/queues/rx-*.
>
> On virtio-net currently all packets use the map from rx-0, because the
> real rx queue is not known at time of map lookup by get_rps_cpu.
>
> Call skb_record_rx_queue in the driver rx path to make lookup work.
>
> Recording the receive queue has ramifications beyond RPS, such as in
> sticky load balancing decisions for sockets (skb_tx_hash) and XPS.
>
> Reported-by: Mark Hlady <[email protected]>
> Signed-off-by: Willem de Bruijn <[email protected]>
And any examples how to see the benefit of this?
> ---
> drivers/net/virtio_net.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0237250860467..236ba5d5fb4bb 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1035,6 +1035,7 @@ static void receive_buf(struct virtnet_info *vi, struct
> receive_queue *rq,
> goto frame_err;
> }
>
> + skb_record_rx_queue(skb, vq2rxq(rq->vq));
> skb->protocol = eth_type_trans(skb, dev);
> pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
> ntohs(skb->protocol), skb->len, skb->pkt_type);
> --
> 2.20.1.321.g9e740568ce-goog
