Re: GRO aggregation
From: Eric Dumazet <hidden>
Date: 2012-09-13 12:34:37
Subsystem:
mellanox ethernet driver (mlx4_en), mellanox mlx4 core vpi driver, networking drivers, the rest · Maintainers:
Tariq Toukan, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
On Thu, 2012-09-13 at 14:05 +0200, Eric Dumazet wrote:
quoted hunk ↗ jump to hunk
But there is no real difference in throughput.diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index 6c4f935..435c35e 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h@@ -96,8 +96,8 @@ /* Receive fragment sizes; we use at most 4 fragments (for 9600 byte MTU * and 4K allocations) */ enum { - FRAG_SZ0 = 512 - NET_IP_ALIGN, - FRAG_SZ1 = 1024, + FRAG_SZ0 = 1536 - NET_IP_ALIGN, + FRAG_SZ1 = 2048, FRAG_SZ2 = 4096, FRAG_SZ3 = MLX4_EN_ALLOC_SIZE };
Oh well, adding one prefetch() is giving ~10% more throughput. I guess this mlx4 driver needs some care.
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 5aba5ec..547eec8 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c@@ -38,6 +38,7 @@ #include <linux/if_ether.h> #include <linux/if_vlan.h> #include <linux/vmalloc.h> +#include <linux/prefetch.h> #include "mlx4_en.h"
@@ -617,7 +618,8 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud !((dev->features & NETIF_F_LOOPBACK) || priv->validate_loopback)) goto next; - + /* avoid cache miss in tcp_gro_receive() */ + prefetch((char *)ethh + 64); /* * Packet is OK - process it. */