Re: [PATCH v2 net-next] tcp: allow drivers to tweak TSQ logic

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 11 Nov 2017 15:54:12 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> I had many reports that TSQ logic breaks wifi aggregation.
> 
> Current logic is to allow up to 1 ms of bytes to be queued into qdisc
> and drivers queues.
> 
> But Wifi aggregation needs a bigger budget to allow bigger rates to
> be discovered by various TCP Congestion Controls algorithms.
> 
> This patch adds an extra socket field, allowing wifi drivers to select
> another log scale to derive TCP Small Queue credit from current pacing
> rate.
> 
> Initial value is 10, meaning that this patch does not change current
> behavior.
> 
> We expect wifi drivers to set this field to smaller values (tests have
> been done with values from 6 to 9)
> 
> They would have to use following template :
> 
> if (skb->sk && skb->sk->sk_pacing_shift != MY_PACING_SHIFT)
>      skb->sk->sk_pacing_shift = MY_PACING_SHIFT;
> 
> 
> Ref: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1670041
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Johannes Berg <johannes.berg@intel.com>
> Cc: Toke Høiland-Jørgensen <toke@toke.dk>
> Cc: Kir Kolyshkin <kir@openvz.org>
> ---
> v2: added kernel-doc comment, based on Johannes feedback.

Applied, thanks Eric.