> > On 6/21/2021 1:30 PM, Ananyev, Konstantin wrote: > > > >> > >>> From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Ananyev, > >>> Konstantin > >>> > >>>>> How can we hide the callbacks since they are used by inline burst > >>> functions. > >>>> > >>>> I probably I owe a better explanation to what I meant in first mail. > >>>> Otherwise it sounds confusing. > >>>> I'll try to write a more detailed one in next few days. > >>> > >>> Actually I gave it another thought over weekend, and might be we can > >>> hide rte_eth_dev_cb even in a simpler way. I'd use eth_rx_burst() as > >>> an example, but the same principle applies to other 'fast' functions. > >>> > >>> 1. Needed changes for PMDs rx_pkt_burst(): > >>> a) change function prototype to accept 'uint16_t port_id' and > >>> 'uint16_t queue_id', > >>> instead of current 'void *'. > >>> b) Each PMD rx_pkt_burst() will have to call rte_eth_rx_epilog() > >>> function at return. > >>> This inline function will do all CB calls for that queue. > >>> > >>> To be more specific, let say we have some PMD: xyz with RX function: > >>> > >>> uint16_t > >>> xyz_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t > >>> nb_pkts) > >>> { > >>> struct xyz_rx_queue *rxq = rx_queue; > >>> uint16_t nb_rx = 0; > >>> > >>> /* do actual stuff here */ > >>> .... > >>> return nb_rx; > >>> } > >>> > >>> It will be transformed to: > >>> > >>> uint16_t > >>> xyz_recv_pkts(uint16_t port_id, uint16_t queue_id, struct rte_mbuf > >>> **rx_pkts, uint16_t nb_pkts) > >>> { > >>> struct xyz_rx_queue *rxq; > >>> uint16_t nb_rx; > >>> > >>> rxq = _rte_eth_rx_prolog(port_id, queue_id); > >>> if (rxq == NULL) > >>> return 0; > >>> nb_rx = _xyz_real_recv_pkts(rxq, rx_pkts, nb_pkts); > >>> return _rte_eth_rx_epilog(port_id, queue_id, rx_pkts, > >>> nb_pkts); > >>> } > >>> > >>> And somewhere in ethdev_private.h: > >>> > >>> static inline void * > >>> _rte_eth_rx_prolog(uint16_t port_id, uint16_t queue_id); > >>> { > >>> struct rte_eth_dev *dev = &rte_eth_devices[port_id]; > >>> > >>> #ifdef RTE_ETHDEV_DEBUG_RX > >>> RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, NULL); > >>> RTE_FUNC_PTR_OR_ERR_RET(*dev->rx_pkt_burst, NULL); > >>> > >>> if (queue_id >= dev->data->nb_rx_queues) { > >>> RTE_ETHDEV_LOG(ERR, "Invalid RX queue_id=%u\n", > >>> queue_id); > >>> return NULL; > >>> } > >>> #endif > >>> return dev->data->rx_queues[queue_id]; > >>> } > >>> > >>> static inline uint16_t > >>> _rte_eth_rx_epilog(uint16_t port_id, uint16_t queue_id, struct rte_mbuf > >>> **rx_pkts, const uint16_t nb_pkts); > >>> { > >>> struct rte_eth_dev *dev = &rte_eth_devices[port_id]; > >>> > >>> #ifdef RTE_ETHDEV_RXTX_CALLBACKS > >>> struct rte_eth_rxtx_callback *cb; > >>> > >>> /* __ATOMIC_RELEASE memory order was used when the > >>> * call back was inserted into the list. > >>> * Since there is a clear dependency between loading > >>> * cb and cb->fn/cb->next, __ATOMIC_ACQUIRE memory order is > >>> * not required. > >>> */ > >>> cb = __atomic_load_n(&dev->post_rx_burst_cbs[queue_id], > >>> __ATOMIC_RELAXED); > >>> > >>> if (unlikely(cb != NULL)) { > >>> do { > >>> nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, > >>> nb_rx, > >>> nb_pkts, cb->param); > >>> cb = cb->next; > >>> } while (cb != NULL); > >>> } > >>> #endif > >>> > >>> rte_ethdev_trace_rx_burst(port_id, queue_id, (void **)rx_pkts, > >>> nb_rx); > >>> return nb_rx; > >>> } > >> > >> That would make the compiler inline _rte_eth_rx_epilog() into the driver > >> when compiling the DPDK library. But > >> RTE_ETHDEV_RXTX_CALLBACKS is a definition for the application developer to > >> use when compiling the DPDK application. > > > > I believe it is for both - user app and DPDK drivers. > > AFAIK, they both have to use the same rte_config.h, otherwise things will > > be broken. > > If let say RTE_ETHDEV_RXTX_CALLBACKS is not enabled in ethdev, then > > user wouldn't be able to add a callback at first place. > > BTW, such change will allow us to make RTE_ETHDEV_RXTX_CALLBACKS > > internal for ethdev/PMD layer, which is a good thing from my perspective. > > > > It is possible to use binary drivers (.so) as plugin. Currently application > can > decide to use or not use Rx/Tx callbacks even with binary drivers, but this > change adds a complexity to this usecase.
Not sure I understand you here... Can you explain a bit more what do you mean? > > >> > >>> > >>> Now, as you said above, in rte_ethdev.h we will keep only a flat array > >>> with pointers to 'fast' functions: > >>> struct { > >>> eth_rx_burst_t rx_pkt_burst > >>> eth_tx_burst_t tx_pkt_burst; > >>> eth_tx_prep_t tx_pkt_prepare; > >>> ..... > >>> } rte_eth_dev_burst[]; > >>> > >>> And rte_eth_rx_burst() will look like: > >>> > >>> static inline uint16_t > >>> rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id, > >>> struct rte_mbuf **rx_pkts, const uint16_t nb_pkts) > >>> { > >>> if (port_id >= RTE_MAX_ETHPORTS) > >>> return 0; > >>> return rte_eth_dev_burst[port_id](port_id, queue_id, rx_pkts, > >>> nb_pkts); > >>> } > >>> > >>> Yes, it will require changes in *all* PMDs, but as I said before the > >>> changes will be a mechanic ones.