Re: [PATCH net-next] mlx4: change TX coalescing defaults

From: Eric Dumazet <redacted>
Date: Mon, 05 Nov 2012 18:20:42 -0800

From: Eric Dumazet <edumazet@google.com>

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 <redacted>
Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied, thanks Eric.