[dpdk-dev] [PATCH v2] net/i40e: set no drop for traffic class

Wu, Jingjing jingjing.wu at intel.com
Tue Feb 7 16:25:54 CET 2017



> -----Original Message-----
> From: Sexton, Rory
> Sent: Thursday, January 19, 2017 6:38 PM
> To: Wu, Jingjing <jingjing.wu at intel.com>
> Cc: dev at dpdk.org; Marjanovic, Nemanja <nemanja.marjanovic at intel.com>
> Subject: RE: [PATCH v2] net/i40e: set no drop for traffic class
> 
> Perhaps the best solution is as suggested to set rte_eth_conf.dcb_capability_en
> = ETH_DCB_PFC_SUPPORT rte_eth_conf.rxmode.mq_mode =
> ETH_MQ_RX_DCB_FLAG and set rte_eth_dcb_rx_conf.nb_tcs to the number of
> tc's to apply Using this port configuration will give the same behavior of the
> patch and it removes the need for an API change.
> 
> Rory
> 
Yes, That's what I thought when the v1 patch. So do we still need this patch now?

> -----Original Message-----
> From: Wu, Jingjing
> Sent: Tuesday, January 17, 2017 3:09 PM
> To: Sexton, Rory <rory.sexton at intel.com>
> Cc: dev at dpdk.org; Marjanovic, Nemanja <nemanja.marjanovic at intel.com>
> Subject: RE: [PATCH v2] net/i40e: set no drop for traffic class
> 
> 
> 
> > -----Original Message-----
> > From: Sexton, Rory
> > Sent: Monday, January 16, 2017 11:52 PM
> > To: Wu, Jingjing <jingjing.wu at intel.com>
> > Cc: dev at dpdk.org; Sexton, Rory <rory.sexton at intel.com>; Marjanovic,
> > Nemanja <nemanja.marjanovic at intel.com>
> > Subject: [PATCH v2] net/i40e: set no drop for traffic class
> >
> > From: Rory Sexton <rory.sexton at intel.com>
> >
> > The default traffic class in i40e is set to drop versus on ixgbe it
> > isset to no drop. This means when packets build up in the RX SRAM on
> > the NIC, they are dropped, and they do this when the SW descriptor rings fill up.
> >
> > This patch changes this behaviour and our testing shows there are no
> > drops as a result.
> >
> > Signed-off-by: Rory Sexton <rory.sexton at intel.com>
> > Signed-off-by: Nemanja Marjanovic <nemanja.marjanovic at intel.com>
> > ---
> > v2:
> > * Changed to use existing api to set priority register directly.
> >
> >  drivers/net/i40e/i40e_ethdev.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/net/i40e/i40e_ethdev.c
> > b/drivers/net/i40e/i40e_ethdev.c index 67778ba..97339b5 100644
> > --- a/drivers/net/i40e/i40e_ethdev.c
> > +++ b/drivers/net/i40e/i40e_ethdev.c
> > @@ -2985,8 +2985,11 @@ static int
> >  i40e_priority_flow_ctrl_set(__rte_unused struct rte_eth_dev *dev,
> >  			    __rte_unused struct rte_eth_pfc_conf *pfc_conf) {
> > +	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data-
> > >dev_private);
> > +
> >  	PMD_INIT_FUNC_TRACE();
> >
> > +	I40E_WRITE_REG(hw, I40E_PRTDCB_TC2PFC, 0xff);
> 
> PRTDCB_TC2PFC  is the Bitmap who controls the use of Priority Flow Control
> (PFC) per each TC. Bit n set to 1b indicates TC n uses PFC in Rx and Tx. The TC is
> referred as a no-drop TC.
> 
> And if look the rte_eth_pfc_conf, there is a field called priority, which would
> map to a TC.
> Currently, the TC and priority is 1:1 map when dcb is enabled.
> So how about change it like:
> Check dcb info, and map the priority to tc, then val = 0x1 << tc;
> I40E_WRITE_REG(hw, I40E_PRTDCB_TC2PFC, val);
> 
> Thanks
> Jingjing
> 
> 
> 
> >  	return -ENOSYS;
> >  }
> >
> > --
> > 2.4.3



More information about the dev mailing list