Re: [dpdk-dev] [PATCH v5 4/6] ether: Check VMDq RSS mode

[Vlad Zolotarov <vladz@cloudius-systems.com>]

On 01/12/15 05:41, Ouyang, Changchun wrote:
>
> *From:*Vlad Zolotarov [mailto:vladz@cloudius-systems.com]
> *Sent:* Friday, January 09, 2015 9:50 PM
> *To:* Ouyang, Changchun; dev@dpdk.org
> *Subject:* Re: [dpdk-dev] [PATCH v5 4/6] ether: Check VMDq RSS mode
>
> On 01/09/15 07:54, Ouyang, Changchun wrote:
>
>       
>
>       
>
>         -----Original Message-----
>
>         From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com]
>
>         Sent: Friday, January 9, 2015 2:49 AM
>
>         To: Ouyang, Changchun;dev@dpdk.org  <mailto:dev@dpdk.org>
>
>         Subject: Re: [dpdk-dev] [PATCH v5 4/6] ether: Check VMDq RSS mode
>
>           
>
>           
>
>         On 01/08/15 11:19, Vlad Zolotarov wrote:
>
>               
>
>             On 01/07/15 08:32, Ouyang Changchun wrote:
>
>                 Check mq mode for VMDq RSS, handle it correctly instead of returning
>
>                 an error; Also remove the limitation of per pool queue number has max
>
>                 value of 1, because the per pool queue number could be 2 or 4 if it
>
>                 is VMDq RSS mode;
>
>                   
>
>                 The number of rxq specified in config will determine the mq mode for
>
>                 VMDq RSS.
>
>                   
>
>                 Signed-off-by: Changchun Ouyang<changchun.ouyang@intel.com>  <mailto:changchun.ouyang@intel.com>
>
>                   
>
>                 changes in v5:
>
>                     - Fix '<' issue, it should be '<=' to test rxq number;
>
>                     - Extract a function to remove the embeded switch-case statement.
>
>                   
>
>                 ---
>
>                    lib/librte_ether/rte_ethdev.c | 50
>
>                 ++++++++++++++++++++++++++++++++++++++-----
>
>                    1 file changed, 45 insertions(+), 5 deletions(-)
>
>                   
>
>                 diff --git a/lib/librte_ether/rte_ethdev.c
>
>                 b/lib/librte_ether/rte_ethdev.c index 95f2ceb..8363e26 100644
>
>                 --- a/lib/librte_ether/rte_ethdev.c
>
>                 +++ b/lib/librte_ether/rte_ethdev.c
>
>                 @@ -503,6 +503,31 @@ rte_eth_dev_tx_queue_config(struct
>
>         rte_eth_dev
>
>                 *dev, uint16_t nb_queues)
>
>                    }
>
>                      static int
>
>                 +rte_eth_dev_check_vf_rss_rxq_num(uint8_t port_id, uint16_t nb_rx_q)
>
>                 +{
>
>                 +    struct rte_eth_dev *dev = &rte_eth_devices[port_id];
>
>                 +    switch (nb_rx_q) {
>
>                 +    case 1:
>
>                 +    case 2:
>
>                 +        RTE_ETH_DEV_SRIOV(dev).active =
>
>                 +            ETH_64_POOLS;
>
>                 +        break;
>
>                 +    case 4:
>
>                 +        RTE_ETH_DEV_SRIOV(dev).active =
>
>                 +            ETH_32_POOLS;
>
>                 +        break;
>
>                 +    default:
>
>                 +        return -EINVAL;
>
>                 +    }
>
>                 +
>
>                 +    RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool = nb_rx_q;
>
>                 +    RTE_ETH_DEV_SRIOV(dev).def_pool_q_idx =
>
>                 +        dev->pci_dev->max_vfs * nb_rx_q;
>
>                 +
>
>                 +    return 0;
>
>                 +}
>
>                 +
>
>                 +static int
>
>                    rte_eth_dev_check_mq_mode(uint8_t port_id, uint16_t nb_rx_q,
>
>                 uint16_t nb_tx_q,
>
>                                  const struct rte_eth_conf *dev_conf)
>
>                    {
>
>                 @@ -510,8 +535,7 @@ rte_eth_dev_check_mq_mode(uint8_t port_id,
>
>                 uint16_t nb_rx_q, uint16_t nb_tx_q,
>
>                          if (RTE_ETH_DEV_SRIOV(dev).active != 0) {
>
>                            /* check multi-queue mode */
>
>                 -        if ((dev_conf->rxmode.mq_mode == ETH_MQ_RX_RSS) ||
>
>                 -            (dev_conf->rxmode.mq_mode == ETH_MQ_RX_DCB) ||
>
>                 +        if ((dev_conf->rxmode.mq_mode == ETH_MQ_RX_DCB) ||
>
>                                (dev_conf->rxmode.mq_mode == ETH_MQ_RX_DCB_RSS) ||
>
>                                (dev_conf->txmode.mq_mode == ETH_MQ_TX_DCB)) {
>
>                                /* SRIOV only works in VMDq enable mode */ @@ -525,7
>
>                 +549,6 @@ rte_eth_dev_check_mq_mode(uint8_t port_id, uint16_t
>
>                 nb_rx_q, uint16_t nb_tx_q,
>
>                            }
>
>                              switch (dev_conf->rxmode.mq_mode) {
>
>                 -        case ETH_MQ_RX_VMDQ_RSS:
>
>                            case ETH_MQ_RX_VMDQ_DCB:
>
>                            case ETH_MQ_RX_VMDQ_DCB_RSS:
>
>                                /* DCB/RSS VMDQ in SRIOV mode, not implement yet */ @@
>
>                 -534,6 +557,25 @@ rte_eth_dev_check_mq_mode(uint8_t port_id,
>
>         uint16_t
>
>                 nb_rx_q, uint16_t nb_tx_q,
>
>                                        "unsupported VMDQ mq_mode rx %u\n",
>
>                                        port_id, dev_conf->rxmode.mq_mode);
>
>                                return (-EINVAL);
>
>                 +        case ETH_MQ_RX_RSS:
>
>                 +            PMD_DEBUG_TRACE("ethdev port_id=%" PRIu8
>
>                 +                    " SRIOV active, "
>
>                 +                    "Rx mq mode is changed from:"
>
>                 +                    "mq_mode %u into VMDQ mq_mode %u\n",
>
>                 +                    port_id,
>
>                 +                    dev_conf->rxmode.mq_mode,
>
>                 +                    dev->data->dev_conf.rxmode.mq_mode);
>
>                 +        case ETH_MQ_RX_VMDQ_RSS:
>
>                 +            dev->data->dev_conf.rxmode.mq_mode =
>
>         ETH_MQ_RX_VMDQ_RSS;
>
>                 +            if (nb_rx_q <= RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool)
>
>                 +                if (rte_eth_dev_check_vf_rss_rxq_num(port_id,
>
>                 nb_rx_q) != 0) {
>
>                 +                    PMD_DEBUG_TRACE("ethdev port_id=%d"
>
>                 +                        " SRIOV active, invalid queue"
>
>                 +                        " number for VMDQ RSS\n",
>
>                 +                        port_id);
>
>               
>
>             Some nitpicking here: I'd add the allowed values descriptions to the
>
>             error message. Something like: "invalid queue number for VMDQ RSS.
>
>             Allowed values are 1, 2 or 4\n".
>
>               
>
>                 +                    return -EINVAL;
>
>                 +                }
>
>                 +            break;
>
>                            default: /* ETH_MQ_RX_VMDQ_ONLY or ETH_MQ_RX_NONE */
>
>                                /* if nothing mq mode configure, use default scheme */
>
>                                dev->data->dev_conf.rxmode.mq_mode =
>
>                 ETH_MQ_RX_VMDQ_ONLY; @@ -553,8 +595,6 @@
>
>                 rte_eth_dev_check_mq_mode(uint8_t port_id, uint16_t nb_rx_q,
>
>         uint16_t nb_tx_q,
>
>                            default: /* ETH_MQ_TX_VMDQ_ONLY or ETH_MQ_TX_NONE */
>
>                                /* if nothing mq mode configure, use default scheme */
>
>                                dev->data->dev_conf.txmode.mq_mode =
>
>         ETH_MQ_TX_VMDQ_ONLY;
>
>                 -            if (RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool > 1)
>
>                 -                RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool = 1;
>
>               
>
>             I'm not sure u may just remove it. These lines originally belong to a
>
>             different flow. Are u sure u can remove them like that? What if the
>
>             mq_mode is ETH_MQ_RX_NONE and nb_q_per_pool has been initialized
>
>         to 4
>
>             or 8 in ixgbe_pf_host_init()?
>
>           
>
>         I misread the patch - these lines belong to the txmode.mq_mode switch case.
>
>         I think it's ok to remove these really strange lines here. And when I look at it i
>
>         think for the similar reasons the similar lines should be removed in the Rx
>
>         case too: consider non-RSS case with MQ DCB Tx configuration.
>
>           
>
>     I search code in this function, only one place has
>
>     " if (RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool > 1)
>
>                 RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool = 1;"
>
>       
>
>     The only place is default branch, which is for rx_none, or vmdq_only mode,
>
>
> Here is a snippet of an rte_eth_dev_check_mq_mode() from the current 
> master:
>
>                 switch (dev_conf->rxmode.mq_mode) {
>                 case ETH_MQ_RX_VMDQ_RSS:
>                 case ETH_MQ_RX_VMDQ_DCB:
>                 case ETH_MQ_RX_VMDQ_DCB_RSS:
>                         /* DCB/RSS VMDQ in SRIOV mode, not implement yet */
>                         PMD_DEBUG_TRACE("ethdev port_id=%" PRIu8
>                                        " SRIOV active, "
>                                        "unsupported VMDQ mq_mode rx %u\n",
>                                        port_id, dev_conf->rxmode.mq_mode);
>                         return (-EINVAL);
>                 default: /* ETH_MQ_RX_VMDQ_ONLY or ETH_MQ_RX_NONE */
>                         /* if nothing mq mode configure, use default scheme */
>                         dev->data->dev_conf.rxmode.mq_mode = ETH_MQ_RX_VMDQ_ONLY;
>                         *if (RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool > 1)                 <---- This is one*
> *                                RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool = 1;*
>                         break;
>                 }
>   
>                 switch (dev_conf->txmode.mq_mode) {
>                 case ETH_MQ_TX_VMDQ_DCB:
>                         /* DCB VMDQ in SRIOV mode, not implement yet */
>                         PMD_DEBUG_TRACE("ethdev port_id=%" PRIu8
>                                        " SRIOV active, "
>                                        "unsupported VMDQ mq_mode tx %u\n",
>                                        port_id, dev_conf->txmode.mq_mode);
>                         return (-EINVAL);
>                 default: /* ETH_MQ_TX_VMDQ_ONLY or ETH_MQ_TX_NONE */
>                         /* if nothing mq mode configure, use default scheme */
>                         dev->data->dev_conf.txmode.mq_mode = ETH_MQ_TX_VMDQ_ONLY;
>                         if (RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool > 1)              <------ This is two. This is what your patch is removing
>                                 RTE_ETH_DEV_SRIOV(dev).nb_q_per_pool = 1;
>                         break;
>                 }
>
>
>
> Changchun: yes you are correct, what I mean in my last response is 
> that only one place AFTER my removal, so there are 2 places before my 
> removal.
> no controversial here.
>
>   
> We don't need remove this, as it should assign as 1 because it did use 1 queue per pool.
>
>
> And why is that? Just because RSS was not enabled? And what if a user 
> wants multiple Tx queues? Mode 1100b of MRQE for instance?
>
> Changchun: I can explain why I need this change(remove the second 
> place) here,
>

I understood why u needed it in the first place. I just say that for 
exactly the same reasons u need to remove the "first place" too. ;)

> In the txmode, when txmode is ETH_MQ_TX_NONE, but the rx mode could 
> either be ETH_MQ_RX_NONE or
>
> ETH_MQ_RX_VMDQ_RSS, so we could not forcedly set nb_q_per_pool into 1 
> just hit the condition of txmode is ETH_MQ_TX_NONE,
>
> Because we need consider it is combination of rx mode is 
> ETH_MQ_RX_VMDQ_RSS, and tx mode is  ETH_MQ_TX_NONE,
>
> In such a case, the queue number per pool could be 1, or 2, or 4.
>
> In another hand, introducing ETH_MQ_TX_VMDQ_RSS for tx mode, seems 
> very strange, because tx side has no rss feature.
>

It's called ETH_MQ_TX_VMDQ_DCB in DPDK notation. ;) However I see that 
it's not yet supported. But *when* it's going to be supported the above 
code will turn to be bogus since u actually don't want to set the 
nb_q_per_pool to 1 neither if Rx mode is not MQ and nor if Tx mode is 
not MQ but only if them **both* *are not MQ. And this "if" is simply 
missing in the rte_eth_dev_check_mq_mode().

>
> thanks Changchun
>
>
>