Hi Morten, On Thu, 31 Jul 2025, Morten Brørup wrote: > When an ethdev port is configured for fast mbuf release, the driver can > use a TX burst function relying on the fast mbuf release preconditions. > Thus, also configuring this port or a queue on the port for transmitting > segmented packets is prohibited. > Checks for these conflicting configurations have been added to the ethdev > library, so the drivers don't have to implement them. > > Also, the descriptions of the RX and TX offloads have been improved, to > reflect that they are not only for device capability reporting, but also > for device and queue configuration purposes. > > Signed-off-by: Morten Brørup > --- > lib/ethdev/rte_ethdev.c | 38 ++++++++++++++++++++++++++++++++++++++ > lib/ethdev/rte_ethdev.h | 20 ++++++++++---------- > 2 files changed, 48 insertions(+), 10 deletions(-) > > diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c > index dd7c00bc94..6570517711 100644 > --- a/lib/ethdev/rte_ethdev.c > +++ b/lib/ethdev/rte_ethdev.c > @@ -1531,6 +1531,18 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q, > goto rollback; > } > > + /* MBUF_FAST_FREE preconditions conflict with MULTI_SEGS support. */ > + if ((dev_conf->txmode.offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) && > + (dev_conf->txmode.offloads & RTE_ETH_TX_OFFLOAD_MULTI_SEGS)) { > + RTE_ETHDEV_LOG_LINE(ERR, > + "Ethdev port_id=%d Tx offload %s conflicts with Tx offload %s", Is it required to spell 'Ethdev ' at start of the line? It was my impression that 'ethdev' would be printed anyway by [1] (the '# t' part). Am I wrong? [1] https://github.com/DPDK/dpdk/blob/b222395561638f89562e4ef42e1eabf2d6db43dd/lib/log/rte_log.h#L334 Thank you. > + port_id, > + rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MULTI_SEGS), > + rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE)); > + ret = -EINVAL; > + goto rollback; > + } > + > dev->data->dev_conf.rx_adv_conf.rss_conf.rss_hf = > rte_eth_rss_hf_refine(dev_conf->rx_adv_conf.rss_conf.rss_hf); > > @@ -2709,6 +2721,32 @@ rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id, > return -EINVAL; > } > > + /* > + * If the driver uses a Tx function with MBUF_FAST_FREE preconditions, > + * per-queue MULTI_SEGS support is not possible. > + */ > + if ((dev->data->dev_conf.txmode.offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) && > + (local_conf.offloads & RTE_ETH_TX_OFFLOAD_MULTI_SEGS)) { > + RTE_ETHDEV_LOG_LINE(ERR, > + "Ethdev port_id=%d tx_queue_id=%d, Tx offload %s conflicts with per-port Tx offload %s", > + port_id, tx_queue_id, > + rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MULTI_SEGS), > + rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE)); > + return -EINVAL; > + } > + /* > + * If the driver uses a Tx function with MULTI_SEGS support, > + * runtime support for per-queue MBUF_FAST_FREE optimization depends on the driver. > + */ > + if ((dev->data->dev_conf.txmode.offloads & RTE_ETH_TX_OFFLOAD_MULTI_SEGS) && > + (local_conf.offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE)) > + RTE_ETHDEV_LOG_LINE(DEBUG, > + "Ethdev port_id=%d tx_queue_id=%d, Tx offload %s potential conflict with per-port Tx offload %s, " > + "runtime support depends on the driver", > + port_id, tx_queue_id, > + rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE), > + rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MULTI_SEGS)); > + > rte_ethdev_trace_txq_setup(port_id, tx_queue_id, nb_tx_desc, tx_conf); > return eth_err(port_id, dev->dev_ops->tx_queue_setup(dev, > tx_queue_id, nb_tx_desc, socket_id, &local_conf)); > diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h > index f9fb6ae549..760a1d2675 100644 > --- a/lib/ethdev/rte_ethdev.h > +++ b/lib/ethdev/rte_ethdev.h > @@ -1550,7 +1550,7 @@ struct rte_eth_conf { > }; > > /** > - * Rx offload capabilities of a device. > + * Rx offload capabilities/configuration of a device or queue. > */ > #define RTE_ETH_RX_OFFLOAD_VLAN_STRIP RTE_BIT64(0) > #define RTE_ETH_RX_OFFLOAD_IPV4_CKSUM RTE_BIT64(1) > @@ -1585,12 +1585,12 @@ struct rte_eth_conf { > RTE_ETH_RX_OFFLOAD_QINQ_STRIP) > > /* > - * If new Rx offload capabilities are defined, they also must be > + * If new Rx offloads are defined, they also must be > * mentioned in rte_rx_offload_names in rte_ethdev.c file. > */ > > /** > - * Tx offload capabilities of a device. > + * Tx offload capabilities/configuration of a device or queue. > */ > #define RTE_ETH_TX_OFFLOAD_VLAN_INSERT RTE_BIT64(0) > #define RTE_ETH_TX_OFFLOAD_IPV4_CKSUM RTE_BIT64(1) > @@ -1611,10 +1611,10 @@ struct rte_eth_conf { > * Tx queue without SW lock. > */ > #define RTE_ETH_TX_OFFLOAD_MT_LOCKFREE RTE_BIT64(14) > -/** Device supports multi segment send. */ > +/** Multi segment send. */ > #define RTE_ETH_TX_OFFLOAD_MULTI_SEGS RTE_BIT64(15) > /** > - * Device supports optimization for fast release of mbufs. > + * Optimization for fast release of mbufs. > * When set application must guarantee that per-queue all mbufs come from the same mempool, > * are direct, have refcnt=1, next=NULL and nb_segs=1, as done by rte_pktmbuf_prefree_seg(). > * > @@ -1623,27 +1623,27 @@ struct rte_eth_conf { > #define RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE RTE_BIT64(16) > #define RTE_ETH_TX_OFFLOAD_SECURITY RTE_BIT64(17) > /** > - * Device supports generic UDP tunneled packet TSO. > + * Generic UDP tunneled packet TSO. > * Application must set RTE_MBUF_F_TX_TUNNEL_UDP and other mbuf fields required > * for tunnel TSO. > */ > #define RTE_ETH_TX_OFFLOAD_UDP_TNL_TSO RTE_BIT64(18) > /** > - * Device supports generic IP tunneled packet TSO. > + * Generic IP tunneled packet TSO. > * Application must set RTE_MBUF_F_TX_TUNNEL_IP and other mbuf fields required > * for tunnel TSO. > */ > #define RTE_ETH_TX_OFFLOAD_IP_TNL_TSO RTE_BIT64(19) > -/** Device supports outer UDP checksum */ > +/** Outer UDP checksum. Used for tunneling packet. */ > #define RTE_ETH_TX_OFFLOAD_OUTER_UDP_CKSUM RTE_BIT64(20) > /** > - * Device sends on time read from RTE_MBUF_DYNFIELD_TIMESTAMP_NAME > + * Send on time read from RTE_MBUF_DYNFIELD_TIMESTAMP_NAME > * if RTE_MBUF_DYNFLAG_TX_TIMESTAMP_NAME is set in ol_flags. > * The mbuf field and flag are registered when the offload is configured. > */ > #define RTE_ETH_TX_OFFLOAD_SEND_ON_TIMESTAMP RTE_BIT64(21) > /* > - * If new Tx offload capabilities are defined, they also must be > + * If new Tx offloads are defined, they also must be > * mentioned in rte_tx_offload_names in rte_ethdev.c file. > */ > > -- > 2.43.0 > >