[dpdk-dev] [PATCH v5 8/9] net/virtio: add in-order Rx/Tx into selection

[Maxime Coquelin]

On 07/02/2018 03:56 PM, Marvin Liu wrote:
> After IN_ORDER Rx/Tx paths added, need to update Rx/Tx path selection
> logic.
> 
> Rx path select logic: If IN_ORDER and merge-able are enabled will select
> IN_ORDER Rx path. If IN_ORDER is enabled, Rx offload and merge-able are
> disabled will select simple Rx path. Otherwise will select normal Rx
> path.
> 
> Tx path select logic: If IN_ORDER is enabled will select IN_ORDER Tx
> path. Otherwise will select default Tx path.
> 
> Signed-off-by: Marvin Liu <yong.liu at intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> 
> diff --git a/doc/guides/nics/virtio.rst b/doc/guides/nics/virtio.rst
> index 46e292c4d..7c099fb7c 100644
> --- a/doc/guides/nics/virtio.rst
> +++ b/doc/guides/nics/virtio.rst
> @@ -201,7 +201,7 @@ The packet transmission flow is:
>   Virtio PMD Rx/Tx Callbacks
>   --------------------------
>   
> -Virtio driver has 3 Rx callbacks and 2 Tx callbacks.
> +Virtio driver has 4 Rx callbacks and 3 Tx callbacks.
>   
>   Rx callbacks:
>   
> @@ -215,6 +215,9 @@ Rx callbacks:
>      Vector version without mergeable Rx buffer support, also fixes the available
>      ring indexes and uses vector instructions to optimize performance.
>   
> +#. ``virtio_recv_mergeable_pkts_inorder``:
> +   In-order version with mergeable Rx buffer support.
> +
>   Tx callbacks:
>   
>   #. ``virtio_xmit_pkts``:
> @@ -223,6 +226,8 @@ Tx callbacks:
>   #. ``virtio_xmit_pkts_simple``:
>      Vector version fixes the available ring indexes to optimize performance.
>   
> +#. ``virtio_xmit_pkts_inorder``:
> +   In-order version.
>   
>   By default, the non-vector callbacks are used:
>   
> @@ -254,6 +259,12 @@ Example of using the vector version of the virtio poll mode driver in
>   
>      testpmd -l 0-2 -n 4 -- -i --tx-offloads=0x0 --rxq=1 --txq=1 --nb-cores=1
>   
> +In-order callbacks only work on simulated virtio user vdev.
> +
> +*   For Rx: If mergeable Rx buffers is enabled and in-order is enabled then
> +    ``virtio_xmit_pkts_inorder`` is used.
> +
> +*   For Tx: If in-order is enabled then ``virtio_xmit_pkts_inorder`` is used.
>   
>   Interrupt mode
>   --------------
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index df50a571a..df7981ddb 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -1320,6 +1320,11 @@ set_rxtx_funcs(struct rte_eth_dev *eth_dev)
>   		PMD_INIT_LOG(INFO, "virtio: using simple Rx path on port %u",
>   			eth_dev->data->port_id);
>   		eth_dev->rx_pkt_burst = virtio_recv_pkts_vec;
> +	} else if (hw->use_inorder_rx) {
> +		PMD_INIT_LOG(INFO,
> +			"virtio: using inorder mergeable buffer Rx path on port %u",
> +			eth_dev->data->port_id);
> +		eth_dev->rx_pkt_burst = &virtio_recv_mergeable_pkts_inorder;
>   	} else if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
>   		PMD_INIT_LOG(INFO,
>   			"virtio: using mergeable buffer Rx path on port %u",
> @@ -1335,6 +1340,10 @@ set_rxtx_funcs(struct rte_eth_dev *eth_dev)
>   		PMD_INIT_LOG(INFO, "virtio: using simple Tx path on port %u",
>   			eth_dev->data->port_id);
>   		eth_dev->tx_pkt_burst = virtio_xmit_pkts_simple;
> +	} else if (hw->use_inorder_tx) {
> +		PMD_INIT_LOG(INFO, "virtio: using inorder Tx path on port %u",
> +			eth_dev->data->port_id);
> +		eth_dev->tx_pkt_burst = virtio_xmit_pkts_inorder;
>   	} else {
>   		PMD_INIT_LOG(INFO, "virtio: using standard Tx path on port %u",
>   			eth_dev->data->port_id);
> @@ -1874,20 +1883,27 @@ virtio_dev_configure(struct rte_eth_dev *dev)
>   	hw->use_simple_rx = 1;
>   	hw->use_simple_tx = 1;
>   
> +	if (vtpci_with_feature(hw, VIRTIO_F_IN_ORDER)) {
> +		/* Simple Tx not compatible with in-order ring */
> +		hw->use_inorder_tx = 1;
> +		hw->use_simple_tx = 0;
> +		if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> +			hw->use_inorder_rx = 1;
> +			hw->use_simple_rx = 0;
> +		} else {
> +			hw->use_inorder_rx = 0;
> +			if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
> +					   DEV_RX_OFFLOAD_TCP_CKSUM))
> +				hw->use_simple_rx = 0;
It is applied, but I think this is still not good.

Simple Rx is set to 1 by default, so if IN_ORDER isn't negotiated,
and UDP/TCP_CSUM is enabled, simple Rx keeps being selected.

I'll fix it in my series that I'm doing on top.

Regards,
Maxime

> +		}
> +	}
> +
>   #if defined RTE_ARCH_ARM64 || defined RTE_ARCH_ARM
>   	if (!rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON)) {
>   		hw->use_simple_rx = 0;
>   		hw->use_simple_tx = 0;
>   	}
>   #endif
> -	if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> -		hw->use_simple_rx = 0;
> -		hw->use_simple_tx = 0;
> -	}
> -
> -	if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
> -			   DEV_RX_OFFLOAD_TCP_CKSUM))
> -		hw->use_simple_rx = 0;
>   
>   	return 0;
>   }
>