[dpdk-dev] MLX5 QP creation failure - cannot allocate memory

[Amedeo Sapio]

Hi all,

I am developing a DPDK program using a Mellanox ConnectX-5 100G.
My program starts N workers (one per core), and each worker deals with its
own dedicated TX and RX queue, therefore I need to setup N TX and N RX
queues.

For each RX queue I create a mbuf pool with:
n = 262144
cache size = 512
priv_size = 0
data_room_size = RTE_MBUF_DEFAULT_BUF_SIZE

For N<=4 everything works fine, but with N=8,  'rte_eth_dev_start' returns:
"Unknown error -12"
and the following error:
net_mlx5: port 0 Tx queue 0 QP creation failure
net_mlx5: port 0 Tx queue allocation failed: Cannot allocate memory

I tried
- to increment the number of Hugepages (up to 64x1G)
- change the pool size in different ways
- both dpdk 18.05 and 18.11

but with no success. Do you have any suggestions on what could be the issue?

Thanks for your help,
---
Amedeo