Patch "net/mlx5e: Fix small packet threshold" has been added to the 4.9-stable tree
Subsystems (3)
This is a note to let you know that I've just added the patch titled
net/mlx5e: Fix small packet threshold
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-mlx5e-fix-small-packet-threshold.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From foo@baz Sat Apr 29 08:22:13 CEST 2017
From: Eugenia Emantayev <[email protected]>
Date: Wed, 22 Mar 2017 11:44:14 +0200
Subject: net/mlx5e: Fix small packet threshold
From: Eugenia Emantayev <[email protected]>
[ Upstream commit cbad8cddb6ed7ef3a5f0a9a70f1711d4d7fb9a8f ]
RX packet headers are meant to be contained in SKB linear part,
and chose a threshold of 128.
It turns out this is not enough, i.e. for IPv6 packet over VxLAN.
In this case, UDP/IPv4 needs 42 bytes, GENEVE header is 8 bytes,
and 86 bytes for TCP/IPv6. In total 136 bytes that is more than current 128 bytes. In this case expand header flow is reached.
The warning in skb_try_coalesce() caused by a wrong truesize
was already fixed here:
commit 158f323b9868 ("net: adjust skb->truesize in pskb_expand_head()"). Still, we prefer to totally avoid the expand header flow for performance reasons. Tested regular TCP_STREAM with iperf for 1 and 8 streams, no degradation was found.
--- drivers/net/ethernet/mellanox/mlx5/core/en.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/net/ethernet/mellanox/mlx5/core/en.h +1 -1
@@ -82,7 +82,7 @@#define MLX5E_VALID_NUM_MTTS (num_mtts) (MLX5_MTT_OCTW(num_mtts) <= U16_MAX)#define MLX5_UMR_ALIGN (2048) -#define MLX5_MPWRQ_SMALL_PACKET_THRESHOLD (128) +#define MLX5_MPWRQ_SMALL_PACKET_THRESHOLD (256)#define MLX5E_PARAMS_DEFAULT_LRO_WQE_SZ (64 * 1024)#define MLX5E_DEFAULT_LRO_TIMEOUT 32
Patches currently in stable-queue which might be from [email protected] are
queue-4.9/net-mlx5e-fix-small-packet-threshold.patch