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

Maxime Coquelin maxime.coquelin at redhat.com
Thu Jun 7 09:34:53 CEST 2018



On 06/07/2018 07:13 AM, Tiwei Bie wrote:
> 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.

Yes, it is better to keep same alignment, even if the rx one looks a bit
weird to me.

Also, I take the opportunity to switch UDP and TXP CKSUM defines for
consistency with Rx.

>> +
>> +	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. :)

Yep, I fix it now.

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

Thanks,
Maxime
> Best regards,
> Tiwei Bie
> 


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