[PATCH net-next 08/15] net/mlx5e: set the tx_queue_len for pfifo_fast

Tariq Toukan
2025-02-09T10:19:39Z

From: William Tu <witu@nvidia.com>

By default, the mq netdev creates a pfifo_fast qdisc. On a
system with 16 core, the pfifo_fast with 3 bands consumes
16 * 3 * 8 (size of pointer) * 1024 (default tx queue len)
= 393KB. The patch sets the tx qlen to representor default
value, 128 (1<<MLX5E_REP_PARAMS_DEF_LOG_SQ_SIZE), which
consumes 16 * 3 * 8 * 128 = 49KB, saving 344KB for each
representor at ECPF.

Signed-off-by: William Tu <witu@nvidia.com>
Reviewed-by: Daniel Jurgens <danielj@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en_rep.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
index da399adc8854..07f38f472a27 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
@@ -889,6 +889,8 @@ static void mlx5e_build_rep_netdev(struct net_device *netdev,
netdev->ethtool_ops = &mlx5e_rep_ethtool_ops;

netdev->watchdog_timeo = 15 * HZ;
+ if (mlx5_core_is_ecpf(mdev))
+ netdev->tx_queue_len = 1 << MLX5E_REP_PARAMS_DEF_LOG_SQ_SIZE;

#if IS_ENABLED(CONFIG_MLX5_CLS_ACT)
netdev->hw_features |= NETIF_F_HW_TC;
--
2.45.0