[dpdk-dev] MLX5 driver - number of descriptors overflow
Amedeo Sapio
amedeo.sapio at gmail.com
Wed Nov 21 10:01:28 CET 2018
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.
Thanks,
---
Amedeo
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