On Thu, Sep 2, 2021 at 7:54 PM Ivan Malov <ivan.ma...@oktetlabs.ru> wrote:
>
> Per-packet meta information (flag, mark and the likes) might
> be expensive to deliver in terms of small packet performance.
> If the features are not enabled by default, enabling them at
> short notice (for example, when a flow rule with action MARK
> gets created) without traffic disruption may not be possible.
>
> Letting applications request delivery of Rx meta information
> during initialisation can solve the said problem efficiently.
>
> Technically, that could be accomplished by defining new bits
> in DEV_RX_OFFLOAD namespace, but the ability to extract meta
> data cannot be considered an offload on its own. For example,
> Rx checksumming is an offload, while mark delivery is not as
> it needs an external party, a flow rule with action MARK, to
> hold the value and trigger mark insertion in the first place.
>
> With this in mind, add a means to let applications negotiate
> adapter support for the very delivery of Rx meta information.
Good stuff.
>
> Signed-off-by: Ivan Malov <ivan.ma...@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>
> ---
> lib/ethdev/ethdev_driver.h | 19 +++++++++++
> lib/ethdev/rte_ethdev.c | 25 +++++++++++++++
> lib/ethdev/rte_ethdev.h | 66 ++++++++++++++++++++++++++++++++++++++
> lib/ethdev/version.map | 3 ++
> 4 files changed, 113 insertions(+)
>
> diff --git a/lib/ethdev/ethdev_driver.h b/lib/ethdev/ethdev_driver.h
> index 40e474aa7e..3e29555fc7 100644
> --- a/lib/ethdev/ethdev_driver.h
> +++ b/lib/ethdev/ethdev_driver.h
> @@ -789,6 +789,22 @@ typedef int (*eth_get_monitor_addr_t)(void *rxq,
> typedef int (*eth_representor_info_get_t)(struct rte_eth_dev *dev,
> struct rte_eth_representor_info *info);
>
> +/**
> + * @internal
> + * Negotiate support for specific fractions of Rx meta information.
> + *
> + * @param[in] dev
> + * Port (ethdev) handle
> + *
> + * @param[inout] features
All the params are in by default, I think, only [out] only needed.
> + * Feature selection buffer
> + *
> + * @return
> + * Negative errno value on error, zero otherwise
> + */
> +typedef int (*eth_negotiate_rx_meta_t)(struct rte_eth_dev *dev,
> + uint64_t *features);
> +
> /**
> * @internal A structure containing the functions exported by an Ethernet
> driver.
> */
> @@ -949,6 +965,9 @@ struct eth_dev_ops {
>
> eth_representor_info_get_t representor_info_get;
> /**< Get representor info. */
> +
> + eth_negotiate_rx_meta_t negotiate_rx_meta;
> + /**< Negotiate support for specific fractions of Rx meta information.
> */
> };
>
> /**
> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
> index 9d95cd11e1..821450cbf9 100644
> --- a/lib/ethdev/rte_ethdev.c
> +++ b/lib/ethdev/rte_ethdev.c
> @@ -6311,6 +6311,31 @@ rte_eth_representor_info_get(uint16_t port_id,
> return eth_err(port_id, (*dev->dev_ops->representor_info_get)(dev,
> info));
> }
>
> +int
> +rte_eth_negotiate_rx_meta(uint16_t port_id, uint64_t *features)
> +{
> + struct rte_eth_dev *dev;
> +
> + RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> + dev = &rte_eth_devices[port_id];
> +
> + if (dev->data->dev_configured != 0) {
> + RTE_ETHDEV_LOG(ERR,
> + "The port (id=%"PRIu16") is already configured\n",
> + port_id);
> + return -EBUSY;
> + }
> +
> + if (features == NULL) {
> + RTE_ETHDEV_LOG(ERR, "Invalid features (NULL)\n");
> + return -EINVAL;
> + }
> +
> + RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->negotiate_rx_meta, -ENOTSUP);
> + return eth_err(port_id,
> + (*dev->dev_ops->negotiate_rx_meta)(dev, features));
> +}
> +
> RTE_LOG_REGISTER_DEFAULT(rte_eth_dev_logtype, INFO);
>
> RTE_INIT(ethdev_init_telemetry)
> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index d2b27c351f..ac4d164aa8 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -4888,6 +4888,72 @@ __rte_experimental
> int rte_eth_representor_info_get(uint16_t port_id,
> struct rte_eth_representor_info *info);
>
> +/**
> + * The ethdev will be able to detect flagged packets provided that
> + * there are active flow rules comprising the corresponding action.
> + */
> +#define RTE_ETH_RX_META_USER_FLAG (UINT64_C(1) << 0)
I think, we need to add @see note in rte_flow API where this is requested.
> +
> +/**
> + * The ethdev will manage to see mark IDs in packets provided that
> + * there are active flow rules comprising the corresponding action.
> + */
> +#define RTE_ETH_RX_META_USER_MARK (UINT64_C(1) << 1)
Same as above
> +
> +/**
> + * The ethdev will be able to identify partially offloaded packets
> + * and process rte_flow_get_restore_info() invocations accordingly
> + * provided that there're so-called "tunnel_set" flow rules in use.
> + */
> +#define RTE_ETH_RX_META_TUNNEL_ID (UINT64_C(1) << 2)
Same as above
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
> + * Negotiate support for specific fractions of Rx meta information.
> + *
> + * This function has to be invoked as early as possible, precisely,
> + * before the first rte_eth_dev_configure() invocation, to let the
> + * PMD make preparations which might be hard to do on later stages.
> + *
> + * The negotiation process is assumed to be carried out as follows:
> + *
> + * - the application composes a mask of preferred Rx meta features
> + * intending to enable at least some of them and invokes the API;
> + *
> + * - the ethdev driver reports back the optimal (from its point of
> + * view) subset of the initial feature set thus agreeing to make
> + * those comprising the subset simultaneously available to users;
> + *
> + * - should the application find the result unsatisfactory, it may
> + * come up with another pick of preferred features and try again;
> + *
> + * - the application can pass zero to clear the negotiation result;
> + *
> + * - the last negotiated result takes effect upon the ethdev start.
> + *
> + * If the method itself is unsupported by the PMD, the application
> + * may just ignore that and proceed with the rest of configuration
> + * procedure intending to simply try using the features it prefers.
> + *
> + * @param[in] port_id
> + * Port (ethdev) identifier
See above comment.
> + *
> + * @param[inout] features
> + * Feature selection buffer
> + *
> + * @return
> + * - (-EBUSY) if the port can't handle this in its current state;
> + * - (-ENOTSUP) if the method itself is not supported by the PMD;
> + * - (-ENODEV) if *port_id* is invalid;
> + * - (-EINVAL) if *features* is NULL;
> + * - (-EIO) if the device is removed;
> + * - (0) on success
> + */
> +__rte_experimental
> +int rte_eth_negotiate_rx_meta(uint16_t port_id, uint64_t *features);
# I would prefer to call it as rte_eth_rx_meta_negotiate as
action/verb can come the last API to
to have a proper namespace.
# IMO, We need to update the release notes for this behavior change.
# Is any of the in-tree examples or test application needs to update
to adaptor this behavior change
> +
> #include <rte_ethdev_core.h>
>
> /**
> diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map
> index 3eece75b72..e390e5718c 100644
> --- a/lib/ethdev/version.map
> +++ b/lib/ethdev/version.map
> @@ -249,6 +249,9 @@ EXPERIMENTAL {
> rte_mtr_meter_policy_delete;
> rte_mtr_meter_policy_update;
> rte_mtr_meter_policy_validate;
> +
> + # added in 21.11
> + rte_eth_negotiate_rx_meta;
> };
>
> INTERNAL {
> --
> 2.20.1
>
