path: root/drivers/net/mlx5/mlx5_rxq.c
diff options
authorYongseok Koh <>2018-10-25 06:24:00 +0000
committerFerruh Yigit <>2018-11-05 15:01:25 +0100
commitbc91e8db12cdc214184ae2114a2ccdd6e273ee3a (patch)
tree8d5be15596d51da6a3d7305199095400e2db277f /drivers/net/mlx5/mlx5_rxq.c
parent84be903c0cc06b5400d5185af82200fab96d7488 (diff)
net/mlx5: add 128B padding of Rx completion entry
A PMD parameter (rxq_cqe_pad_en) is added to enable 128B padding of CQE on RX side. The size of CQE is aligned with the size of a cacheline of the core. If cacheline size is 128B, the CQE size is configured to be 128B even though the device writes only 64B data on the cacheline. This is to avoid unnecessary cache invalidation by device's two consecutive writes on to one cacheline. However in some architecture, it is more beneficial to update entire cacheline with padding the rest 64B rather than striding because read-modify-write could drop performance a lot. On the other hand, writing extra data will consume more PCIe bandwidth and could also drop the maximum throughput. It is recommended to empirically set this parameter. Disabled by default. Signed-off-by: Yongseok Koh <> Acked-by: Shahaf Shuler <>
Diffstat (limited to 'drivers/net/mlx5/mlx5_rxq.c')
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index ed993ea..7db3f68 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -841,6 +841,12 @@ mlx5_rxq_ibv_new(struct rte_eth_dev *dev, uint16_t idx)
" timestamp",
+ if (config->cqe_pad) {
+ attr.cq.mlx5.comp_mask |= MLX5DV_CQ_INIT_ATTR_MASK_FLAGS;
+ attr.cq.mlx5.flags |= MLX5DV_CQ_INIT_ATTR_FLAGS_CQE_PAD;
+ }
tmpl->cq = mlx5_glue->cq_ex_to_cq
(mlx5_glue->dv_create_cq(priv->ctx, &attr.cq.ibv,