Re: [dpdk-dev] [PATCH v1] ena_ethdev: don't override the user provided queue length value

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/9/2020 10:07 AM, Chauskin, Igor wrote:
> Acked inline
> 
> From: Vladislav Zolotarov <vladz@scylladb.com>
> Sent: Friday, March 6, 2020 12:28 AM
> To: dev@dpdk.org; Schmeilin, Evgeny <evgenys@amazon.com>; Chauskin, Igor <igorch@amazon.com>
> Subject: RE: [EXTERNAL][dpdk-dev] [PATCH v1] ena_ethdev: don't override the user provided queue length value
> 
> Igor, Evgeny,
> Please, review.
> On 3/5/20 5:23 PM, Vlad Zolotarov wrote:
> 
> There is a funny logic that seems to be outdated which tries to detect
> 
> a situation when a user requests a default size of the queue and
> 
> configures a device specific default value.
> 
> 
> 
> This seems to be not in line with the DPDK current design that expects
> 
> the user to go via the rte_eth_dev_info_get() in order to get device
> 
> specific values.
> 
> 
> 
> And if the user doesn't care it should pass 0 as a queue length and this
> 
> case is also being taken care of on the rte_eth level.
> 
> 
> 
> Signed-off-by: Vlad Zolotarov <vladz@scylladb.com><mailto:vladz@scylladb.com>
> 
> Acked-by: Igor Chauskin igorch@amazon.com<mailto:igorch@amazon.com>
> 
> ---
> 
>  drivers/net/ena/ena_ethdev.c | 6 ------
> 
>  1 file changed, 6 deletions(-)
> 
> 
> 
> diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
> 
> index 665afee4f..bf632dee0 100644
> 
> --- a/drivers/net/ena/ena_ethdev.c
> 
> +++ b/drivers/net/ena/ena_ethdev.c
> 
> @@ -1221,9 +1221,6 @@ static int ena_tx_queue_setup(struct rte_eth_dev *dev,
> 
>          return -EINVAL;
> 
>   }
> 
> 
> 
> - if (nb_desc == RTE_ETH_DEV_FALLBACK_TX_RINGSIZE)
> 
> -        nb_desc = adapter->tx_ring_size;
> 
> -

Logic in ethdev is;

/* Use default specified by driver, if nb_tx_desc is zero */
if (nb_tx_desc == 0) {
        nb_tx_desc = dev_info.default_txportconf.ring_size;
        /* If driver default is zero, fall back on EAL default */
        if (nb_tx_desc == 0)
                nb_tx_desc = RTE_ETH_DEV_FALLBACK_TX_RINGSIZE;
}

User may provide, '0' nb_tx_desc to request driver default value. If there is no
driver default value 'RTE_ETH_DEV_FALLBACK_TX_RINGSIZE' is used.

As driver doesn't support the default value, the ring size still can be set to
'RTE_ETH_DEV_FALLBACK_TX_RINGSIZE'.
Wouldn't be good to add driver default value when removing this check?

> 
>   txq->port_id = dev->data->port_id;
> 
>   txq->next_to_clean = 0;
> 
>   txq->next_to_use = 0;
> 
> @@ -1292,9 +1289,6 @@ static int ena_rx_queue_setup(struct rte_eth_dev *dev,
> 
>          return ENA_COM_FAULT;
> 
>   }
> 
> 
> 
> - if (nb_desc == RTE_ETH_DEV_FALLBACK_RX_RINGSIZE)
> 
> -        nb_desc = adapter->rx_ring_size;
> 
> -
> 
>   if (!rte_is_power_of_2(nb_desc)) {
> 
>          PMD_DRV_LOG(ERR,
> 
>                  "Unsupported size of RX queue: %d is not a power of 2.\n",
>