[dpdk-dev] [PATCH v3 5/6] ixgbe: Config VF RSS

Vladislav Zolotarov vladz at cloudius-systems.com
Fri Dec 26 07:49:24 CET 2014


On Dec 26, 2014 3:52 AM, "Ouyang, Changchun" <changchun.ouyang at intel.com>
wrote:
>
>
>
> > -----Original Message-----
> > From: Vlad Zolotarov [mailto:vladz at cloudius-systems.com]
> > Sent: Thursday, December 25, 2014 9:20 PM
> > To: Ouyang, Changchun; dev at dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v3 5/6] ixgbe: Config VF RSS
> >
> >
> > On 12/25/14 04:43, Ouyang, Changchun wrote:
> > > Hi,
> > > Sorry miss some comments, so continue my response below,
> > >
> > >> -----Original Message-----
> > >> From: Vlad Zolotarov [mailto:vladz at cloudius-systems.com]
> > >> Sent: Wednesday, December 24, 2014 6:40 PM
> > >> To: Ouyang, Changchun; dev at dpdk.org
> > >> Subject: Re: [dpdk-dev] [PATCH v3 5/6] ixgbe: Config VF RSS
> > >>
> > >>
> > >> On 12/24/14 07:23, Ouyang Changchun wrote:
> > >>> It needs config RSS and IXGBE_MRQC and IXGBE_VFPSRTYPE to enable
> > VF
> > >> RSS.
> > >>> The psrtype will determine how many queues the received packets will
> > >>> distribute to, and the value of psrtype should depends on both
facet:
> > >>> max VF rxq number which has been negotiated with PF, and the number
> > >>> of
> > >> rxq specified in config on guest.
> > >>> Signed-off-by: Changchun Ouyang <changchun.ouyang at intel.com>
> > >>> ---
> > >>>    lib/librte_pmd_ixgbe/ixgbe_pf.c   | 15 +++++++
> > >>>    lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 92
> > >> ++++++++++++++++++++++++++++++++++-----
> > >>>    2 files changed, 97 insertions(+), 10 deletions(-)
> > >>>
> > >>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_pf.c
> > >>> b/lib/librte_pmd_ixgbe/ixgbe_pf.c index cbb0145..9c9dad8 100644
> > >>> --- a/lib/librte_pmd_ixgbe/ixgbe_pf.c
> > >>> +++ b/lib/librte_pmd_ixgbe/ixgbe_pf.c
> > >>> @@ -187,6 +187,21 @@ int ixgbe_pf_host_configure(struct rte_eth_dev
> > >> *eth_dev)
> > >>>           IXGBE_WRITE_REG(hw, IXGBE_MPSAR_LO(hw-
> > mac.num_rar_entries), 0);
> > >>>           IXGBE_WRITE_REG(hw, IXGBE_MPSAR_HI(hw-
> > mac.num_rar_entries), 0);
> > >>>
> > >>> + /*
> > >>> +  * VF RSS can support at most 4 queues for each VF, even if
> > >>> +  * 8 queues are available for each VF, it need refine to 4
> > >>> +  * queues here due to this limitation, otherwise no queue
> > >>> +  * will receive any packet even RSS is enabled.
> > >> According to Table 7-3 in the 82599 spec RSS is not available when
> > >> port is configured to have 8 queues per pool. This means that if u
> > >> see this configuration u may immediately disable RSS flow in your
code.
> > >>
> > >>> +  */
> > >>> + if (eth_dev->data->dev_conf.rxmode.mq_mode ==
> > >> ETH_MQ_RX_VMDQ_RSS) {
> > >>> +         if (RTE_ETH_DEV_SRIOV(eth_dev).nb_q_per_pool == 8) {
> > >>> +                 RTE_ETH_DEV_SRIOV(eth_dev).active =
> > >> ETH_32_POOLS;
> > >>> +                 RTE_ETH_DEV_SRIOV(eth_dev).nb_q_per_pool = 4;
> > >>> +                 RTE_ETH_DEV_SRIOV(eth_dev).def_pool_q_idx =
> > >>> +                         dev_num_vf(eth_dev) * 4;
> > >> According to 82599 spec u can't do that since RSS is not allowed when
> > >> port is configured to have 8 function per-VF. Have u verified that
> > >> this works? If yes, then spec should be updated.
> > >>
> > >>> +         }
> > >>> + }
> > >>> +
> > >>>           /* set VMDq map to default PF pool */
> > >>>           hw->mac.ops.set_vmdq(hw, 0,
> > >>> RTE_ETH_DEV_SRIOV(eth_dev).def_vmdq_idx);
> > >>>
> > >>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > >>> b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > >>> index f69abda..a7c17a4 100644
> > >>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > >>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > >>> @@ -3327,6 +3327,39 @@ ixgbe_alloc_rx_queue_mbufs(struct
> > >> igb_rx_queue *rxq)
> > >>>    }
> > >>>
> > >>>    static int
> > >>> +ixgbe_config_vf_rss(struct rte_eth_dev *dev) {
> > >>> + struct ixgbe_hw *hw;
> > >>> + uint32_t mrqc;
> > >>> +
> > >>> + ixgbe_rss_configure(dev);
> > >>> +
> > >>> + hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> > >>> +
> > >>> + /* MRQC: enable VF RSS */
> > >>> + mrqc = IXGBE_READ_REG(hw, IXGBE_MRQC);
> > >>> + mrqc &= ~IXGBE_MRQC_MRQE_MASK;
> > >>> + switch (RTE_ETH_DEV_SRIOV(dev).active) {
> > >>> + case ETH_64_POOLS:
> > >>> +         mrqc |= IXGBE_MRQC_VMDQRSS64EN;
> > >>> +         break;
> > >>> +
> > >>> + case ETH_32_POOLS:
> > >>> + case ETH_16_POOLS:
> > >>> +         mrqc |= IXGBE_MRQC_VMDQRSS32EN;
> > >> Again, this contradicts with the spec.
> > > Yes, the spec say the hw can't support vf rss at all, but experiment
find that
> > could be done.
> >
> > The spec explicitly say that VF RSS *is* supported in particular in the
table
> > mentioned above.
> But the spec(January 2014 revision 2.9) on my hand says: "in IOV mode,
VMDq+RSS mode is not available"  in note of section 4.6.10.2.1

And still there is the whole section about configuring packet filtering
including Rx in the VF mode (including the table i've referred) . It's
quite confusing i must say...

> > What your code is doing is that in case of 16 VFs u setup a 32 pools
> > configuration and use only 16 out of them.
> But I don't see any big issue here, in this case, each vf COULD have 8
queues, like I said before, but this is estimation value, actually only 4
queues
> Are really available for one vf, you can refer to spec for the
correctness here.

No issues, i just wanted to clarify that it seems like you are doing it
quite according to the spec.

> >
> > > We can focus on discussing the implementation firstly.

Right. So, after we clarified that there is nothing u can do at the moment
about the rss query flow, there is  one more open issue here.
In general we need a way to know how many  queues from those that are
available may be configured as RSS. While the same issue is present with
the PF as well (it's 16 for 82599 but it may be a different number for a
different device) for VF it's more pronounced since it depends on the PF
configuration.

Don't u think it would be logical to add a specific filed for it in the
dev_info struct?

> >
> > >
> > >>> +         break;
> > >>> +
> > >>> + default:
> > >>> +         PMD_INIT_LOG(ERR, "Invalid pool number in IOV mode");
> > >>> +         return -EINVAL;
> > >>> + }
> > >>> +
> > >>> + IXGBE_WRITE_REG(hw, IXGBE_MRQC, mrqc);
> > >>> +
> > >>> + return 0;
> > >>> +}
> > >>> +
> > >>> +static int
> > >>>    ixgbe_dev_mq_rx_configure(struct rte_eth_dev *dev)
> > >>>    {
> > >>>           struct ixgbe_hw *hw =
> > >>> @@ -3358,24 +3391,38 @@ ixgbe_dev_mq_rx_configure(struct
> > >> rte_eth_dev *dev)
> > >>>                           default: ixgbe_rss_disable(dev);
> > >>>                   }
> > >>>           } else {
> > >>> -         switch (RTE_ETH_DEV_SRIOV(dev).active) {
> > >>>                   /*
> > >>>                    * SRIOV active scheme
> > >>>                    * FIXME if support DCB/RSS together with VMDq &
SRIOV
> > >>>                    */
> > >>> -         case ETH_64_POOLS:
> > >>> -                 IXGBE_WRITE_REG(hw, IXGBE_MRQC,
> > >> IXGBE_MRQC_VMDQEN);
> > >>> +         switch (dev->data->dev_conf.rxmode.mq_mode) {
> > >>> +         case ETH_MQ_RX_RSS:
> > >>> +         case ETH_MQ_RX_VMDQ_RSS:
> > >>> +                 ixgbe_config_vf_rss(dev);
> > >>>                           break;
> > >>>
> > >>> -         case ETH_32_POOLS:
> > >>> -                 IXGBE_WRITE_REG(hw, IXGBE_MRQC,
> > >> IXGBE_MRQC_VMDQRT4TCEN);
> > >>> -                 break;
> > >>> +         default:
> > >>> +                 switch (RTE_ETH_DEV_SRIOV(dev).active) {
> > >> Sorry for nitpicking but have u considered taking this encapsulated
> > >> "switch- case" block into a separate function? This could make the
> > >> code look a lot nicer. ;)
> > >>
> > >>> +                 case ETH_64_POOLS:
> > >>> +                         IXGBE_WRITE_REG(hw, IXGBE_MRQC,
> > >>> +                                 IXGBE_MRQC_VMDQEN);
> > >>> +                         break;
> > >>>
> > >>> -         case ETH_16_POOLS:
> > >>> -                 IXGBE_WRITE_REG(hw, IXGBE_MRQC,
> > >> IXGBE_MRQC_VMDQRT8TCEN);
> > >>> +                 case ETH_32_POOLS:
> > >>> +                         IXGBE_WRITE_REG(hw, IXGBE_MRQC,
> > >>> +                                 IXGBE_MRQC_VMDQRT4TCEN);
> > >>> +                         break;
> > >>> +
> > >>> +                 case ETH_16_POOLS:
> > >>> +                         IXGBE_WRITE_REG(hw, IXGBE_MRQC,
> > >>> +                                 IXGBE_MRQC_VMDQRT8TCEN);
> > >>> +                         break;
> > >>> +                 default:
> > >>> +                         PMD_INIT_LOG(ERR,
> > >>> +                                 "invalid pool number in IOV
mode");
> > >>> +                         break;
> > >>> +                 }
> > >>>                           break;
> > >>> -         default:
> > >>> -                 PMD_INIT_LOG(ERR, "invalid pool number in IOV
> > >> mode");
> > >>>                   }
> > >>>           }
> > >>>
> > >>> @@ -3989,10 +4036,32 @@ ixgbevf_dev_rx_init(struct rte_eth_dev
> > *dev)
> > >>>           uint16_t buf_size;
> > >>>           uint16_t i;
> > >>>           int ret;
> > >>> + uint16_t valid_rxq_num;
> > >>>
> > >>>           PMD_INIT_FUNC_TRACE();
> > >>>           hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> > >>>
> > >>> + valid_rxq_num = RTE_MIN(dev->data->nb_rx_queues,
> > >>> +hw->mac.max_rx_queues);
> > >>> +
> > >>> + /*
> > >>> +  * VMDq RSS can't support 3 queues, so config it into 4 queues,
> > >>> +  * and give user a hint that some packets may loss if it doesn't
> > >>> +  * poll the queue where those packets are distributed to.
> > >>> +  */
> > >>> + if (valid_rxq_num == 3)
> > >>> +         valid_rxq_num = 4;
> > >> Why to configure more queues that requested and not less (2)? Why to
> > >> configure anything at all and not return an error?
> > > Sorry, I don't agree this is "anything" you say, because I don't use
5,6,7,
> > 8, ..., 16, 2014, 2015,... etc.
> > > By considering 2 or 4,
> > > I prefer 4, the reason is if user need more than 3 queues per vf to do
> > > something, And pf has also the capability to setup 4 queues per vf,
> > > confining to 2 queues is also not good thing, So here try to enable 4
queues,
> > and give user hints here.
> > > Btw, change it into 2 is another way, depends on other guys' more
insight
> > here.
> >
> > Like I said before, trying to guess what user wants is a way to making
a code
> > that is very hard to use and to maintain. Pls., just return an error
and let the
> > user code deal with it the way he/she really wants and not the way u
*think*
> > he/she wants.
> >
> I didn't disagree on this, either :-)
> If you have strong reason for this way and more guys agree with it,
> I will modify it probably in v4.
> > >
> > >>> +
> > >>> + if (dev->data->nb_rx_queues > valid_rxq_num) {
> > >>> +         PMD_INIT_LOG(ERR, "The number of Rx queue invalid, "
> > >>> +                 "it should be equal to or less than %d",
> > >>> +                 valid_rxq_num);
> > >>> +         return -1;
> > >>> + } else if (dev->data->nb_rx_queues < valid_rxq_num)
> > >>> +         PMD_INIT_LOG(ERR, "The number of Rx queue is less "
> > >>> +                 "than the number of available Rx queues:%d, "
> > >>> +                 "packets in Rx queues(q_id >= %d) may loss.",
> > >>> +                 valid_rxq_num, dev->data->nb_rx_queues);
> > >> Who ever looks in the "INIT_LOG" if everything "work well" and u make
> > >> it look so by allowing this call to succeed. And then some packets
> > >> will just silently not arrive?! And what the used should somehow
guess to
> > do?
> > >> - Look in the "INIT_LOG"?! This is a nightmare!
> > >>
> > >>> +
> > >>>           /*
> > >>>            * When the VF driver issues a IXGBE_VF_RESET request,
the PF
> > >> driver
> > >>>            * disables the VF receipt of packets if the PF MTU is >
1500.
> > >>> @@ -4094,6 +4163,9 @@ ixgbevf_dev_rx_init(struct rte_eth_dev *dev)
> > >>>                           IXGBE_PSRTYPE_IPV6HDR;
> > >>>    #endif
> > >>>
> > >>> + /* Set RQPL for VF RSS according to max Rx queue */
> > >>> + psrtype |= (valid_rxq_num >> 1) <<
> > >>> +         IXGBE_PSRTYPE_RQPL_SHIFT;
> > >>>           IXGBE_WRITE_REG(hw, IXGBE_VFPSRTYPE, psrtype);
> > >>>
> > >>>           if (dev->data->dev_conf.rxmode.enable_scatter) {
>


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