From ecfd2ce1a9d5e6376ff5c00b366345160abdbbb7 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 5 Nov 2012 16:20:42 +0000
Subject: [PATCH] mlx4: change TX coalescing defaults
mlx4 currently uses a too high tx coalescing setting, deferring
TX completion interrupts by up to 128 us.
With the recent skb_orphan() removal in commit 8112ec3b872,
performance of a single TCP flow is capped to ~4 Gbps, unless
we increase tcp_limit_output_bytes.
I suggest using 16 us instead of 128 us, allowing a finer control.
Performance of a single TCP flow is restored to previous levels,
while keeping TCP small queues fully enabled with default sysctl.
This patch is also a BQL prereq.
Reported-by: Vimalkumar <j.vimal@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yevgeny Petrilin <yevgenyp@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Acked-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 2 +-
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index edd9cb8d3e1d..2b23ca21b320 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -870,7 +870,7 @@ static void mlx4_en_set_default_moderation(struct mlx4_en_priv *priv)
/* If we haven't received a specific coalescing setting
* (module param), we set the moderation parameters as follows:
* - moder_cnt is set to the number of mtu sized packets to
- * satisfy our coelsing target.
+ * satisfy our coalescing target.
* - moder_time is set to a fixed value.
*/
priv->rx_frames = MLX4_EN_RX_COAL_TARGET;
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 9d27e42264e2..8a5e70d68894 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -126,7 +126,7 @@ enum {
#define MLX4_EN_RX_COAL_TIME 0x10
#define MLX4_EN_TX_COAL_PKTS 16
-#define MLX4_EN_TX_COAL_TIME 0x80
+#define MLX4_EN_TX_COAL_TIME 0x10
#define MLX4_EN_RX_RATE_LOW 400000
#define MLX4_EN_RX_COAL_TIME_LOW 0
--
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