Re: [dpdk-dev] [PATCH] app/testpmd: fix DCB config issue on ixgbe

["Lu, Wenzhuo" <wenzhuo.lu@intel.com>]

Hi Bernard,

> > > >
> > > > The return value of rte_eth_dev_configure() should be checked.
> > > > Calling rte_eth_dev_configure() with  parameters nb_rx_q and
> > > > nb_tx_q equal to 0 returns -EINVAL, and does nothing.
> > > > Should the values of nb_rx_q and nb_tx_q be non zero?
> > The 0 is used on purpose. Because I don't want to configure the
> > queues. The only purpose is to  make all the configuration to write
> > into the device. And that's why the return value is ignored by (void).
> 
> It might be useful to add a comment to explain why rte_eth_dev_configure() is
> being called in this way.
Thanks for the suggestion. I'll add it:)

> > >
> > > If nb_rxq and nb_txq are set to max_rx_queues and max_tx_queues
> > > respectively, there is a failure when the port is started in
> > > ixgbe_check_mq_mode() at line
> > > 1990 in ixgbe_ethdev.c.
> > > SRIOV is active, nb_rx_q=128 nb_tx_q=128 queue number must be less
> > > than or equal to 1.
> > I haven't hit this issue. Would you like to give more details about
> > how to hit it? I'll check if I miss something.
> 
> There is a Niantic PF and VF bound to igb_uio. Port 0 is the PF and Port 1 is the
> VF.
> ./testpmd -c 3f -l 1-5 -n 4 -- -i
> testpmd> set corelist 2,3,4,5
> testpmd> port stop 0  /* PF is 0 */
> testpmd> port config 0 dcb vt on 4 pfc on port start 0 /* PF is 0 */
> line 1990   ixgbe_ethdev.c
> SRIOV is active, nb_rx_q=128 nb_tx_q=128 queue number must be less than or
> equal to 1.
> /* Works if nb_rx_q and nb_tx_q set to 1 */
To my opinion, it's a by-design limitation. After using the DCB configuration CLI, the queue number is set to a fix number which is the max number. But as you pointed, when SRIOV is active there's another requirement for the queue number.
We need to investigate deeper and find a solution for it. But I think it's another story. We need another patch for it.

> 
> testpmd> show port dcb_tc 0
> ================ DCB infos for port 0   ================
>   TC NUMBER: 4  (showing 8 a lot of the time ??)   /* port start should be called
> first */
>   TC :             0       1       2       3
>   Priority :       0       1       2       3
>   BW percent :    25%     25%     25%     25%
>   RXQ base :       0       1       2       3
>   RXQ number :     1       1       1       1
>   TXQ base :       0       1       2       3
>   TXQ number :     1       1       1       1
> testpmd> show port dcb_tc 1
>  Failed to get dcb infos on port 1
> 
> > >
> > > nb_rxq and nb_txq are equal to 1 at this point, if they are not
> > > changed, port start completes successfully.
> > >
> > >
> > > > >  	} else {
> > > > >  		/*if vt is disabled, use all pf queues */
> > > > > -		if (dev_info.vmdq_pool_base == 0) {
> > > > > -			nb_rxq = dev_info.max_rx_queues;
> > > > > -			nb_txq = dev_info.max_tx_queues;
> > > > > +		if (rte_port->dev_info.vmdq_pool_base == 0) {
> > > > > +			nb_rxq = rte_port->dev_info.max_rx_queues;
> > > > > +			nb_txq = rte_port->dev_info.max_tx_queues;
> > > > >  		} else {
> > > > >  			nb_rxq = (queueid_t)num_tcs;
> > > > >  			nb_txq = (queueid_t)num_tcs; @@ -1997,16 +2010,6
> @@
> > > > > init_port_dcb_config(portid_t pid,
> > > > >  	}
> > > > >  	rx_free_thresh = 64;
> > > > >
> > > > > -	memset(&port_conf, 0, sizeof(struct rte_eth_conf));
> > > > > -	/* Enter DCB configuration status */
> > > > > -	dcb_config = 1;
> > > > > -
> > > > > -	/*set configuration of DCB in vt mode and DCB in non-vt mode*/
> > > > > -	retval = get_eth_dcb_conf(&port_conf, dcb_mode, num_tcs,
> > > > > pfc_en);
> > > > > -	if (retval < 0)
> > > > > -		return retval;
> > > > > -
> > > > > -	rte_port = &ports[pid];
> > > > >  	memcpy(&rte_port->dev_conf, &port_conf, sizeof(struct
> > > > > rte_eth_conf));
> > > > >
> > > > >  	rxtx_port_config(rte_port);
> > > > > --
> > > > > 1.9.3
> Regards,
> 
> Bernard