Re: [dpdk-dev] [PATCH v2 3/5] net/vhost: improve Tx path selection

[Tiwei Bie <tiwei.bie@intel.com>]

On Wed, Jun 06, 2018 at 02:31:26PM +0200, Maxime Coquelin wrote:
[...]
> @@ -1886,6 +1888,15 @@ virtio_dev_configure(struct rte_eth_dev *dev)
>  			(1ULL << VIRTIO_NET_F_GUEST_TSO4) |
>  			(1ULL << VIRTIO_NET_F_GUEST_TSO6);
>  
> +	if (tx_offloads & (DEV_TX_OFFLOAD_TCP_CKSUM |
> +				DEV_TX_OFFLOAD_UDP_CKSUM))
> +		req_features |= (1ULL << VIRTIO_NET_F_CSUM);

Hmm.. I still prefer to keep the DEV_TX_OFFLOAD_TCP_CKSUM
and DEV_TX_OFFLOAD_UDP_CKSUM aligned to make the coding
style consistent with the existing code of Rx:

1901 ¦       if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
1902 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_CKSUM))
1903 ¦       ¦       req_features |= (1ULL << VIRTIO_NET_F_GUEST_CSUM);

But it's up to you.

> +
> +	if (tx_offloads & DEV_TX_OFFLOAD_TCP_TSO)
> +		req_features |=
> +			(1ULL << VIRTIO_NET_F_HOST_TSO4) |
> +			(1ULL << VIRTIO_NET_F_HOST_TSO6);
> +
>  	/* if request features changed, reinit the device */
>  	if (req_features != hw->req_guest_features) {
>  		ret = virtio_init_device(dev, req_features);
> @@ -1955,6 +1966,12 @@ virtio_dev_configure(struct rte_eth_dev *dev)
>  			   DEV_RX_OFFLOAD_TCP_CKSUM))
>  		hw->use_simple_rx = 0;
>  
> +	if (tx_offloads & (DEV_TX_OFFLOAD_TCP_CKSUM |
> +				DEV_TX_OFFLOAD_UDP_CKSUM |
> +				DEV_TX_OFFLOAD_TCP_TSO |
> +				DEV_TX_OFFLOAD_VLAN_INSERT))
> +		hw->use_simple_tx = 0;

Ditto. Below is the code for Rx:

1987 ¦       if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
1988 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_CKSUM |
1989 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_LRO |
1990 ¦       ¦       ¦          DEV_RX_OFFLOAD_VLAN_STRIP))
1991 ¦       ¦       hw->use_simple_rx = 0;

So, instead of:

1987 ¦       if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
1988 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_CKSUM |
1989 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_LRO |
1990 ¦       ¦       ¦          DEV_RX_OFFLOAD_VLAN_STRIP))
1991 ¦       ¦       hw->use_simple_rx = 0;
1992
1993 ¦       if (tx_offloads & (DEV_TX_OFFLOAD_TCP_CKSUM |
1994 ¦       ¦       ¦       ¦       DEV_TX_OFFLOAD_UDP_CKSUM |
1995 ¦       ¦       ¦       ¦       DEV_TX_OFFLOAD_TCP_TSO |
1996 ¦       ¦       ¦       ¦       DEV_TX_OFFLOAD_VLAN_INSERT))
1997 ¦       ¦       hw->use_simple_tx = 0;

I would prefer:

1987 ¦       if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
1988 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_CKSUM |
1989 ¦       ¦       ¦          DEV_RX_OFFLOAD_TCP_LRO |
1990 ¦       ¦       ¦          DEV_RX_OFFLOAD_VLAN_STRIP))
1991 ¦       ¦       hw->use_simple_rx = 0;
1992
1993 ¦       if (tx_offloads & (DEV_TX_OFFLOAD_UDP_CKSUM |
1994 ¦       ¦       ¦          DEV_TX_OFFLOAD_TCP_CKSUM |
1995 ¦       ¦       ¦          DEV_TX_OFFLOAD_TCP_TSO |
1996 ¦       ¦       ¦          DEV_TX_OFFLOAD_VLAN_INSERT))
1997 ¦       ¦       hw->use_simple_tx = 0;

But anyway, it's up to you. :)

Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>

Best regards,
Tiwei Bie