[dpdk-dev] [PATCH v3 08/11] net/virtio: add in-order Rx/Tx into selection

Liu, Yong yong.liu at intel.com
Thu Jun 28 17:39:43 CEST 2018



> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin at redhat.com]
> Sent: Thursday, June 28, 2018 11:16 PM
> To: Liu, Yong <yong.liu at intel.com>; Bie, Tiwei <tiwei.bie at intel.com>
> Cc: Wang, Zhihong <zhihong.wang at intel.com>; dev at dpdk.org
> Subject: Re: [PATCH v3 08/11] net/virtio: add in-order Rx/Tx into
> selection
> 
> 
> 
> On 06/28/2018 11:52 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 is disabled will select normal Rx
> > path. If IN_ORDER is enabled, Rx offload and merge-able are disabled
> > will select simple Rx path. Otherwise will select IN_ORDER Rx path.
> >
> > Tx path select logic: If IN_ORDER is disabled will select normal Tx
> > path. If IN_ORDER is enabled and merge-able is disabled will select
> > simple Tx path. Otherwise will select IN_ORDER Tx path.
> >
> > Signed-off-by: Marvin Liu <yong.liu at intel.com>
> >
> > diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> > index df50a571a..2b3d65f80 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);
> > @@ -1871,24 +1880,24 @@ virtio_dev_configure(struct rte_eth_dev *dev)
> >
> >   	rte_spinlock_init(&hw->state_lock);
> >
> > -	hw->use_simple_rx = 1;
> > -	hw->use_simple_tx = 1;
> > -
> >   #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 (vtpci_with_feature(hw, VIRTIO_F_IN_ORDER)) {
> > +		if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > +			hw->use_inorder_rx = 1;
> > +			hw->use_inorder_tx = 1;
> > +		} else {
> > +			hw->use_simple_tx = 1;
> > +			if (!(rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
> > +					     DEV_RX_OFFLOAD_TCP_CKSUM)))
> > +				hw->use_simple_rx = 1;
> > +		}
> 
> It seems to be wrong.
> For example if IN_ORDER hasn't been negotiated, we might want to use the
> simple path if no rx offload have been requested by the application.
> 
> It was the case before the patch if I'm not mistaken.

Maxime,
IN_ORDER is the prerequisite for selection simple rx/tx path. So when IN_ORDER + mergeable off + no rx offload will chose simple rx path.

> 
> Also, with ARM platform, we force not to use simple path, but in case
> IN_ORDER has been negotiated but not MRG_RXBUF, it gets re-enabled.

Will move ARM force action behind normal selection, thus can satisfy ARM.

Thanks,
Marvin

> 
> >   	}
> >
> > -	if (rx_offloads & (DEV_RX_OFFLOAD_UDP_CKSUM |
> > -			   DEV_RX_OFFLOAD_TCP_CKSUM))
> > -		hw->use_simple_rx = 0;
> > -
> >   	return 0;
> >   }
> >
> >


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