Re: [dpdk-dev] [PATCH 1/3] event: add function for reading unlink in progress

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Wed, 12 Sep 2018 17:16:14 +0100
> From: Harry van Haaren <harry.van.haaren@intel.com>
> To: dev@dpdk.org
> CC: jerin.jacob@caviumnetworks.com, matias.elo@nokia.com, Harry van Haaren
>  <harry.van.haaren@intel.com>
> Subject: [PATCH 1/3] event: add function for reading unlink in progress
> X-Mailer: git-send-email 2.17.1
> 
> 
> This commit introduces a new function in the eventdev API,
> which allows applications to read the number of unlink requests
> in progress on a particular port of an eventdev instance.
> 
> This information allows applications to verify when no more packets
> from a particular queue (or any queue) will arrive at a port.
> The application could decide to stop polling, or put the core into
> a sleep state if it wishes, as it is ensured that no new packets
> will arrive at a particular port anymore if all queues are unlinked.
> 
> Suggested-by: Matias Elo <matias.elo@nokia.com>
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> 
> ---
> 
> Cc: jerin.jacob@caviumnetworks.com
> 
> Hey, I've added this API as __rte_experimental, so we should be OK to
> include in 18.11, and then possibly remove the experimental tag in
> a later release, assuming it serves its purpose correctly.
> 
> For context, see thread here:
> http://mails.dpdk.org/archives/dev/2018-September/111499.html
> 
> @Matias, is that workable for you?
> @Jerin, is this acceptable as maintainer?


Yes.

Overall patch looks good to me. Please find inline a minor comment.

# There is build error in this series(not in this patch), please check error log

/export/dpdk-next-eventdev/drivers/event/sw/sw_evdev.c: In function
‘sw_port_unlinks_in_progress’:
/export/dpdk-next-eventdev/drivers/event/sw/sw_evdev.c:124:50: error:
unused parameter ‘dev’ [-Werror=unused-parameter]
 sw_port_unlinks_in_progress(struct rte_eventdev *dev, void *port)


With above changes:

Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com

> 
> Cheers, -Harry
> ---
>  lib/librte_eventdev/rte_eventdev.c           | 22 +++++++++++++++
>  lib/librte_eventdev/rte_eventdev.h           | 28 ++++++++++++++++++--
>  lib/librte_eventdev/rte_eventdev_pmd.h       | 19 +++++++++++++
>  lib/librte_eventdev/rte_eventdev_version.map |  1 +
>  4 files changed, 68 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eventdev/rte_eventdev.c b/lib/librte_eventdev/rte_eventdev.c
> index 801810edd..0a8572b7b 100644
> --- a/lib/librte_eventdev/rte_eventdev.c
> +++ b/lib/librte_eventdev/rte_eventdev.c
> @@ -980,6 +980,28 @@ rte_event_port_unlink(uint8_t dev_id, uint8_t port_id,
>         return diag;
>  }
> 
> +int __rte_experimental
> +rte_event_port_unlinks_in_progress(uint8_t dev_id, uint8_t port_id)
> +{
> +       struct rte_eventdev *dev;
> +
> +       RTE_EVENTDEV_VALID_DEVID_OR_ERR_RET(dev_id, -EINVAL);
> +       dev = &rte_eventdevs[dev_id];
> +       if (!is_valid_port(dev, port_id)) {
> +               RTE_EDEV_LOG_ERR("Invalid port_id=%" PRIu8, port_id);
> +               return -EINVAL;
> +       }
> +
> +       /* Return 0 if the PMD does not implement unlinks in progress.
> +        * This allows PMDs which handle unlink synchronously to not implement
> +        * this function at all.
> +        */
> +       RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->port_unlinks_in_progress, 0);
> +
> +       return (*dev->dev_ops->port_unlinks_in_progress)(dev,
> +                       dev->data->ports[port_id]);
> +}
> +
>  int
>  rte_event_port_links_get(uint8_t dev_id, uint8_t port_id,
>                          uint8_t queues[], uint8_t priorities[])
> diff --git a/lib/librte_eventdev/rte_eventdev.h b/lib/librte_eventdev/rte_eventdev.h
> index b6fd6ee7f..d07e297bc 100644
> --- a/lib/librte_eventdev/rte_eventdev.h
> +++ b/lib/librte_eventdev/rte_eventdev.h
> @@ -1656,8 +1656,9 @@ rte_event_port_link(uint8_t dev_id, uint8_t port_id,
>   * event port designated by its *port_id* on the event device designated
>   * by its *dev_id*.
>   *
> - * The unlink establishment shall disable the event port *port_id* from
> - * receiving events from the specified event queue *queue_id*
> + * The unlink call issues an async request to disable the event port *port_id*
> + * from receiving events from the specified event queue *queue_id*. See
> + * *rte_event_port_unlinks_in_progress* to poll for completed unlinks.

use @see rte_event_port_unlinks_in_progress() like reset of file.


>   *
>   * Event queue(s) to event port unlink establishment can be changed at runtime
>   * without re-configuring the device.
> @@ -1694,6 +1695,29 @@ int
>  rte_event_port_unlink(uint8_t dev_id, uint8_t port_id,
>                       uint8_t queues[], uint16_t nb_unlinks);
> 
> +/**
> + * Returns the number of unlinks in progress.
> + *
> + * This function provides the application with a method to detect when an
> + * unlink has been completed by the implementation. See *rte_event_port_unlink*
> + * on how to issue unlink requests.

Same as above comment.

> + *
> + * @param dev_id
> + *   The indentifier of the device.
> + *
> + * @param port_id
> + *   Event port identifier to select port to check for unlinks in progress.
> + *
> + * @return
> + * The number of unlinks that are in progress. A return of zero indicates that
> + * there are no outstanding unlink requests. A positive return value indicates
> + * the number of unlinks that are in progress, but are not yet complete.
> + * A negative return value indicates an error, -EINVAL indicates an invalid
> + * parameter passed for *dev_id* or *port_id*.
> + */
> +int __rte_experimental
> +rte_event_port_unlinks_in_progress(uint8_t dev_id, uint8_t port_id);
> +
>  /**
>   * Retrieve the list of source event queues and its associated service priority
>   * linked to the destination event port designated by its *port_id*
> diff --git a/lib/librte_eventdev/rte_eventdev_pmd.h b/lib/librte_eventdev/rte_eventdev_pmd.h
> index 3fbb4d2b2..65645730a 100644
> --- a/lib/librte_eventdev/rte_eventdev_pmd.h
> +++ b/lib/librte_eventdev/rte_eventdev_pmd.h
> @@ -332,6 +332,23 @@ typedef int (*eventdev_port_link_t)(struct rte_eventdev *dev, void *port,
>  typedef int (*eventdev_port_unlink_t)(struct rte_eventdev *dev, void *port,
>                 uint8_t queues[], uint16_t nb_unlinks);
>