> On Nov 21, 2018, at 1:01 AM, Amedeo Sapio <amedeo.sa...@gmail.com> wrote: > > Hello, > > I experienced a problem with the MLX5 driver running a code that is working > fine with an Intel card. I have found that the reason of this error is an > overflow of the uint16_t number of descriptors in the mlx driver. > > Here the details: > > - The NIC is a Mellanox ConnectX-5 100G. > > - This is a summary code that I run to initialize the port: > > ret = rte_eth_dev_configure(dpdk_par.portid, 1, 1, &port_conf); > > dpdk_par.port_rx_ring_size = dev_info.rx_desc_lim.nb_max; > dpdk_par.port_tx_ring_size = dev_info.tx_desc_lim.nb_max; > > ret = rte_eth_dev_adjust_nb_rx_tx_desc(dpdk_par.portid, > &dpdk_par.port_rx_ring_size, &dpdk_par.port_tx_ring_size); > > ret = rte_eth_rx_queue_setup(dpdk_par.portid, 0, > dpdk_par.port_rx_ring_size, rte_eth_dev_socket_id(dpdk_par.portid), > &rx_conf, dpdk_data.pool); > ret = rte_eth_tx_queue_setup(dpdk_par.portid, 0, > dpdk_par.port_tx_ring_size, rte_eth_dev_socket_id(dpdk_par.portid), > &tx_conf); > > ret = rte_eth_dev_start(dpdk_par.portid); > > - The "rte_eth_dev_start" function returns -ENOMEM = -12 (Out of memory) > > - I see that "dev_info.rx_desc_lim.nb_max" is 65535. This value is rounded > to the next power of 2 in "mlx5_rx_queue_setup", which overflows and > becomes 0. > > I thought that "rte_eth_dev_adjust_nb_rx_tx_desc" should have adjusted the > value, but clearly it has not.
Nice catch! You are right. We should've set it appropriately. Will come up with a patch. Meanwhile, can you please use a workaround?, e.g., rte_log2_u32(rte_align32prevpow2(dev_info.rx_desc_lim.nb_max)); Will let you know when we push a patch. Thanks, Yongseok
