Re: [dpdk-dev] [PATCH v7] ethdev: check Rx/Tx offloads

[Shahaf Shuler <shahafs@mellanox.com>]

Hi Ferruh, Dai,
> Subject: [dpdk-dev] [PATCH v7] ethdev: check Rx/Tx offloads
> 
> This patch check if a input requested offloading is valid or not.
> Any reuqested offloading must be supported in the device capabilities.
> Any offloading is disabled by default if it is not set in the parameter
> dev_conf->[rt]xmode.offloads to rte_eth_dev_configure( ) and [rt]x_conf-
> >offloads to rte_eth_[rt]x_queue_setup( ).
> From application, a pure per-port offloading can't be enabled on any queue if
> it hasn't been enabled in rte_eth_dev_configure( ).
> If any offloading is enabled in rte_eth_dev_configure( ) by application, it is
> enabled on all queues no matter whether it is per-queue or per-port type
> and no matter whether it is set or cleared in [rt]x_conf->offloads to
> rte_eth_[rt]x_queue_setup( ).
> The underlying PMD must be aware that the requested offloadings to PMD
> specific queue_setup( ) function only carries those offloadings only enabled
> for the queue but not enabled in rte_eth_dev_configure( ) and they are
> certain per-queue type.
> 
> This patch can make above such checking in a common way in rte_ethdev
> layer to avoid same checking in underlying PMD.
> 
> Signed-off-by: Wei Dai <wei.dai@intel.com>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
> ---
> v7:
> Give the maximum freedom for upper application, only minimal checking is
> performed in ethdev layer.
> Only requested specific pure per-queue offloadings are input to underlying
> PMD.
> 
> v6:
> No need enable an offload in queue_setup( ) if it has already been enabled
> in dev_configure( )
> 
> v5:
> keep offload settings sent to PMD same as those from application
> 
> v4:
> fix a wrong description in git log message.
> 
> v3:
> rework according to dicision of offloading API in community
> 
> v2:
> add offloads checking in rte_eth_dev_configure( ).
> check if a requested offloading is supported.
> ---
>  lib/librte_ethdev/rte_ethdev.c | 150
> +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 150 insertions(+)
> 
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index e560524..0ad05eb 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -1139,6 +1139,28 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t
> nb_rx_q, uint16_t nb_tx_q,
>  							ETHER_MAX_LEN;
>  	}
> 
> +	/* Any requested offloading must be within its device capabilities */
> +	if ((local_conf.rxmode.offloads & dev_info.rx_offload_capa) !=
> +	     local_conf.rxmode.offloads) {
> +		RTE_PMD_DEBUG_TRACE("ethdev port_id=%d requested Rx
> offloads "
> +				    "0x%" PRIx64 " doesn't match Rx offloads "
> +				    "capabilities 0x%" PRIx64 "\n",
> +				    port_id,
> +				    local_conf.rxmode.offloads,
> +				    dev_info.rx_offload_capa);
> +		return -EINVAL;

While I am OK with such behavior, we should be more careful not to get into the same issue as in [1].
There are PMD which don't report the capabilities correctly however do expect to have the offload configured.

All I am saying it is worth a check and cautious decision if it is right to include this one w/o prior application notice and at such late RC of the release. 

> +	}
> +	if ((local_conf.txmode.offloads & dev_info.tx_offload_capa) !=
> +	     local_conf.txmode.offloads) {
> +		RTE_PMD_DEBUG_TRACE("ethdev port_id=%d requested Tx
> offloads "
> +				    "0x%" PRIx64 " doesn't match Tx offloads "
> +				    "capabilities 0x%" PRIx64 "\n",
> +				    port_id,
> +				    local_conf.txmode.offloads,
> +				    dev_info.tx_offload_capa);
> +		return -EINVAL;
> +	}
> +
>  	/* Check that device supports requested rss hash functions. */
>  	if ((dev_info.flow_type_rss_offloads |
>  	     dev_conf->rx_adv_conf.rss_conf.rss_hf) != @@ -1414,6 +1436,8
> @@ rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
>  	struct rte_eth_dev_info dev_info;
>  	struct rte_eth_rxconf local_conf;
>  	void **rxq;
> +	uint64_t pure_port_offload_capa;
> +	uint64_t only_enabled_for_queue;
> 
>  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
> 
> @@ -1504,6 +1528,68 @@ rte_eth_rx_queue_setup(uint16_t port_id,
> uint16_t rx_queue_id,
>  						    &local_conf.offloads);
>  	}
> 
> +	/*
> +	 * The requested offloadings by application for this queue
> +	 * can be per-queue type or per-port type. and
> +	 * they must be within the device offloading capabilities.
> +	 */
> +	if ((local_conf.offloads & dev_info.rx_offload_capa) !=
> +	     local_conf.offloads) {
> +		RTE_PMD_DEBUG_TRACE("Ethdev port_id=%d
> rx_queue_id=%d "
> +				    "Requested offload 0x%" PRIx64 "doesn't "
> +				    "match per-queue capability 0x%" PRIx64
> +				    " in %s\n",
> +				    port_id,
> +				    rx_queue_id,
> +				    local_conf.offloads,
> +				    dev_info.rx_queue_offload_capa,
> +				    __func__);
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * A pure per-port offloading can't be enabled for any queue
> +	 * if it hasn't been enabled in rte_eth_dev_configure( ).
> +	 *
> +	 * Following pure_port_offload_capa is the capabilities which
> +	 * can't be enabled on some queue while disabled on other queue.
> +	 * pure_port_offload_capa must be enabled or disabled on all
> +	 * queues at same time.
> +	 *
> +	 * Following only_enabled_for_queue is the offloadings which
> +	 * are enabled for this queue but hasn't been enabled in
> +	 * rte_eth_dev_configure( ).
> +	 */
> +	pure_port_offload_capa = dev_info.rx_offload_capa ^
> +				 dev_info.rx_queue_offload_capa;
> +	only_enabled_for_queue = (local_conf.offloads ^
> +		dev->data->dev_conf.rxmode.offloads) &
> local_conf.offloads;

It looks like above logic could be a lot simpler. 

How about:
local_conf.offloads &= ~dev->data->dev_conf.rxmode.offloads; // keep only the added offloads on top of the port ones
if ((local_conf.offloads & dev_info.rx_queue_offload_capa) !=
    local_conf.offloads) { //check if added offloads are part of the queue offload capa
	ERROR...


> +	if (only_enabled_for_queue & pure_port_offload_capa) {
> +		RTE_PMD_DEBUG_TRACE("Ethdev port_id=%d
> rx_queue_id=%d, only "
> +				    "enabled offload 0x%" PRIx64 "for this "
> +				    "queue haven't been enabled in "
> +				    "dev_configure( ), they are within "
> +				    "pure per-port capabilities 0x%" PRIx64

Need to re-work this error message. The user doesn't know what are "pure per-port capabilities" 

> +				    " in %s\n",
> +				    port_id,
> +				    rx_queue_id,
> +				    only_enabled_for_queue,
> +				    pure_port_offload_capa,
> +				    __func__);
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * If an offloading has already been enabled in
> +	 * rte_eth_dev_configure(), it has been enabled on all queues,
> +	 * so there is no need to enable it in this queue again.
> +	 * The local_conf.offloads input to underlying PMD only carries
> +	 * those offloadings which are only enabled on this queue and
> +	 * not enabled on all queues.
> +	 * The underlying PMD must be aware of this point.
> +	 */
> +	local_conf.offloads &= ~dev->data->dev_conf.rxmode.offloads;
> +
>  	ret = (*dev->dev_ops->rx_queue_setup)(dev, rx_queue_id,
> nb_rx_desc,
>  					      socket_id, &local_conf, mp);
>  	if (!ret) {
> @@ -1549,6 +1635,8 @@ rte_eth_tx_queue_setup(uint16_t port_id,
> uint16_t tx_queue_id,
>  	struct rte_eth_dev_info dev_info;
>  	struct rte_eth_txconf local_conf;
>  	void **txq;
> +	uint64_t pure_port_offload_capa;
> +	uint64_t only_enabled_for_queue;
> 
>  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
> 
> @@ -1612,6 +1700,68 @@ rte_eth_tx_queue_setup(uint16_t port_id,
> uint16_t tx_queue_id,
>  					  &local_conf.offloads);
>  	}
> 
> +	/*
> +	 * The requested offloadings by application for this queue
> +	 * can be per-queue type or per-port type. and
> +	 * they must be within the device offloading capabilities.
> +	 */
> +	if ((local_conf.offloads & dev_info.tx_offload_capa) !=
> +	     local_conf.offloads) {
> +		RTE_PMD_DEBUG_TRACE("Ethdev port_id=%d
> tx_queue_id=%d "
> +				    "Requested offload 0x%" PRIx64 "doesn't "
> +				    "match per-queue capability 0x%" PRIx64
> +				    " in %s\n",
> +				    port_id,
> +				    tx_queue_id,
> +				    local_conf.offloads,
> +				    dev_info.tx_queue_offload_capa,
> +				    __func__);
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * A pure per-port offloading can't be enabled for any queue
> +	 * if it hasn't been enabled in rte_eth_dev_configure( ).
> +	 *
> +	 * Following pure_port_offload_capa is the capabilities which
> +	 * can't be enabled on some queue while disabled on other queue.
> +	 * pure_port_offload_capa must be enabled or disabled on all
> +	 * queues at same time.
> +	 *
> +	 * Following only_enabled_for_queue is the offloadings which
> +	 * are enabled for this queue but hasn't been enabled in
> +	 * rte_eth_dev_configure( ).
> +	 */
> +	pure_port_offload_capa = dev_info.tx_offload_capa ^
> +				 dev_info.tx_queue_offload_capa;
> +	only_enabled_for_queue = (local_conf.offloads ^
> +		dev->data->dev_conf.txmode.offloads) &
> local_conf.offloads;

Same comments as in the Rx part.  

> +	if (only_enabled_for_queue & pure_port_offload_capa) {
> +		RTE_PMD_DEBUG_TRACE("Ethdev port_id=%d
> tx_queue_id=%d, only "
> +				    "enabled offload 0x%" PRIx64 "for this "
> +				    "queue haven't been enabled in "
> +				    "dev_configure( ), they are within "
> +				    "pure per-port capabilities 0x%" PRIx64
> +				    " in %s\n",
> +				    port_id,
> +				    tx_queue_id,
> +				    only_enabled_for_queue,
> +				    pure_port_offload_capa,
> +				    __func__);
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * If an offloading has already been enabled in
> +	 * rte_eth_dev_configure(), it has been enabled on all queues,
> +	 * so there is no need to enable it in this queue again.
> +	 * The local_conf.offloads input to underlying PMD only carries
> +	 * those offloadings which are only enabled on this queue and
> +	 * not enabled on all queues.
> +	 * The underlying PMD must be aware of this point.
> +	 */
> +	local_conf.offloads &= ~dev->data->dev_conf.txmode.offloads;
> +
>  	return eth_err(port_id, (*dev->dev_ops->tx_queue_setup)(dev,
>  		       tx_queue_id, nb_tx_desc, socket_id, &local_conf));  }
> --
> 2.7.5


As for Ferruh's comment
> 
> PMDs needs to be updated for:
> 1- Remove existing offload verify checks
> 2- Update offload configure logic based on new values
> 
> (1) can be part of this patch. But PMD maintainers should send update 
> for (2) if a change required.
>
>cc'ed Shahaf, specially for (2) one.

I think PMD maintainers can help with that. If it will be integrated enough time before the release Mellanox PMDs can be converted by us. 




[1]
http://dpdk.org/dev/patchwork/patch/38645/