Re: [dpdk-dev] [PATCH V2] ethdev: add queue state when retrieve queue information

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> Hi Lijun,
> 
> Let's try to complete this for the release.
> 
> On 4/6/2021 3:02 PM, Ananyev, Konstantin wrote:
> > Hi,
> >
> >> Currently, upper-layer application could get queue state only
> >> through pointers such as dev->data->tx_queue_state[queue_id],
> >> this is not the recommended way to access it. So this patch
> >> add get queue state when call rte_eth_rx_queue_info_get and
> >> rte_eth_tx_queue_info_get API.
> >>
> >> Note: The hairpin queue is not supported with above
> >> rte_eth_*x_queue_info_get, so the queue state could be
> >> RTE_ETH_QUEUE_STATE_STARTED or RTE_ETH_QUEUE_STATE_STOPPED.
> >
> > I wonder why RTE_ETH_QUEUE_STATE_HAIRPIN Is not supported?
> > Obviously what we do - copy internal queue state to the user provided buffer.
> >
> 
> +1, with current implementation we can't say it is only for start & stop.
> 
> Since 'STATE_HAIRPIN' is all internal, it may be possible to separate it into

With this patch - not any more, as we move RTE_ETH_QUEUE_STATE_* Defines
into rte_ethdev.h. 

> its own variable and expose only start and stop, but I don't think it worth the
> effort, why not just expose all possible states.
> 
> 
> >> Note: After add queue_state field, the 'struct rte_eth_rxq_info' size
> >> remains 128B, and the 'struct rte_eth_txq_info' size remains 64B, so
> >> it could be ABI compatible.
> >>
> >> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> >> Signed-off-by: Lijun Ou <oulijun@huawei.com>
> >> ---
> >> V1->V2:
> >> - move queue state defines to public file
> >> ---
> >>   doc/guides/rel_notes/release_21_05.rst |  6 ++++++
> >>   lib/librte_ethdev/ethdev_driver.h      |  7 -------
> >>   lib/librte_ethdev/rte_ethdev.c         |  3 +++
> >>   lib/librte_ethdev/rte_ethdev.h         | 11 +++++++++++
> >>   4 files changed, 20 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/doc/guides/rel_notes/release_21_05.rst b/doc/guides/rel_notes/release_21_05.rst
> >> index 22aa80a..503daf9 100644
> >> --- a/doc/guides/rel_notes/release_21_05.rst
> >> +++ b/doc/guides/rel_notes/release_21_05.rst
> >> @@ -164,6 +164,12 @@ ABI Changes
> >>
> >>   * No ABI change that would break compatibility with 20.11.
> >>
> >> +* Added new field ``queue_state`` to ``rte_eth_rxq_info`` structure
> >> +  to provide indicated rxq queue state.
> >> +
> >> +* Added new field ``queue_state`` to ``rte_eth_txq_info`` structure
> >> +  to provide indicated txq queue state.
> >> +
> >>
> >>   Known Issues
> >>   ------------
> >> diff --git a/lib/librte_ethdev/ethdev_driver.h b/lib/librte_ethdev/ethdev_driver.h
> >> index cdd4b43..ec5a17d 100644
> >> --- a/lib/librte_ethdev/ethdev_driver.h
> >> +++ b/lib/librte_ethdev/ethdev_driver.h
> >> @@ -970,13 +970,6 @@ struct eth_dev_ops {
> >>   };
> >>
> >>   /**
> >> - * RX/TX queue states
> >> - */
> >> -#define RTE_ETH_QUEUE_STATE_STOPPED 0
> >> -#define RTE_ETH_QUEUE_STATE_STARTED 1
> >> -#define RTE_ETH_QUEUE_STATE_HAIRPIN 2
> >> -
> >> -/**
> >>    * @internal
> >>    * Check if the selected Rx queue is hairpin queue.
> >>    *
> >> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> >> index 3059aa5..fbd10b2 100644
> >> --- a/lib/librte_ethdev/rte_ethdev.c
> >> +++ b/lib/librte_ethdev/rte_ethdev.c
> >> @@ -5042,6 +5042,8 @@ rte_eth_rx_queue_info_get(uint16_t port_id, uint16_t queue_id,
> >>
> >>   memset(qinfo, 0, sizeof(*qinfo));
> >>   dev->dev_ops->rxq_info_get(dev, queue_id, qinfo);
> >> +qinfo->queue_state = dev->data->rx_queue_state[queue_id];
> >> +
> >>   return 0;
> >>   }
> >>
> >> @@ -5082,6 +5084,7 @@ rte_eth_tx_queue_info_get(uint16_t port_id, uint16_t queue_id,
> >>
> >>   memset(qinfo, 0, sizeof(*qinfo));
> >>   dev->dev_ops->txq_info_get(dev, queue_id, qinfo);
> >> +qinfo->queue_state = dev->data->tx_queue_state[queue_id];
> >>
> >>   return 0;
> >>   }
> >> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> >> index efda313..4f0b1b2 100644
> >> --- a/lib/librte_ethdev/rte_ethdev.h
> >> +++ b/lib/librte_ethdev/rte_ethdev.h
> >> @@ -1582,6 +1582,13 @@ struct rte_eth_dev_info {
> >>   };
> >>
> >>   /**
> >> + * RX/TX queue states
> >> + */
> >> +#define RTE_ETH_QUEUE_STATE_STOPPED 0
> >> +#define RTE_ETH_QUEUE_STATE_STARTED 1
> >> +#define RTE_ETH_QUEUE_STATE_HAIRPIN 2
> >> +
> >> +/**
> >>    * Ethernet device RX queue information structure.
> >>    * Used to retrieve information about configured queue.
> >>    */
> >> @@ -1591,6 +1598,8 @@ struct rte_eth_rxq_info {
> >>   uint8_t scattered_rx;       /**< scattered packets RX supported. */
> >>   uint16_t nb_desc;           /**< configured number of RXDs. */
> >>   uint16_t rx_buf_size;       /**< hardware receive buffer size. */
> >> +/**< Queues state: STARTED(1) / STOPPED(0). */
> >
> > I think comment has to state that possible values are one of
> > RTE_ETH_QUEUE_STATE_*.
> > About previous discussion about new field in this struct vs new API function,
> > I still think new function will be a bit cleaner, but could live with both.
> >
> >> +uint8_t queue_state;
> >
> > If we'll go with new 1B field, then as Stephen pointed,
> > it is probably worth to fill the hole between scattered_rx
> > and nb_desc with this new filed.
> >
> 
> +1
> 
> >>   } __rte_cache_min_aligned;
> >>
> >>   /**
> >> @@ -1600,6 +1609,8 @@ struct rte_eth_rxq_info {
> >>   struct rte_eth_txq_info {
> >>   struct rte_eth_txconf conf; /**< queue config parameters. */
> >>   uint16_t nb_desc;           /**< configured number of TXDs. */
> >> +/**< Queues state: STARTED(1) / STOPPED(0). */
> >
> > Same about comment here.
> >
> >> +uint8_t queue_state;
> >>   } __rte_cache_min_aligned;
> >>
> >>   /* Generic Burst mode flag definition, values can be ORed. */
> >> --
> >> 2.7.4
> >
> 
> 
> Other comments I case see:
> 
> 1- Make QUEUE_STATE enum
>    For consistency with existing usage I think we can keep it as it is
> 
> 2- Make a specific API to get the queue state
>    No strong opinion, I think we can go with this one
> 
> 3- Use enum type in "struct rte_eth_rxq_info"
>    Which make sense but we don't have space in current struct, also
> 'rte_eth_dev_data' has variable to hold same, and for consistency if we change
> it to enum in it, that is even wider change. I think it doesn't worth the effort
> and we can continue with 'uint8_t'
> 
> Please add if any is missing, and if there is any strong opinion on above.
> 
> 
> If there is no objection, only required changes are above two issues commented
> inline,
> - Remove comment/note that this is only for start/stop states
> - Replace the field location to benefit from gap in struct

Sounds good to me.
Konstantin