netdev - Re: [PATCH net-next 0/6] tcp: remove non GSO code

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Date:   Wed, 21 Feb 2018 14:37:48 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     edumazet@...gle.com
Cc:     netdev@...r.kernel.org, ncardwell@...gle.com, ycheng@...gle.com,
        soheil@...gle.com, oleksandr@...alenko.name, eric.dumazet@...il.com
Subject: Re: [PATCH net-next 0/6] tcp: remove non GSO code

From: Eric Dumazet <edumazet@...gle.com>
Date: Mon, 19 Feb 2018 11:56:46 -0800

> Switching TCP to GSO mode, relying on core networking layers
> to perform eventual adaptation for dumb devices was overdue.
> 
> 1) Most TCP developments are done with TSO in mind.
> 2) Less high-resolution timers needs to be armed for TCP-pacing
> 3) GSO can benefit of xmit_more hint
> 4) Receiver GRO is more effective (as if TSO was used for real on sender)
>    -> less ACK packets and overhead.
> 5) Write queues have less overhead (one skb holds about 64KB of payload)
> 6) SACK coalescing just works. (no payload in skb->head)
> 7) rtx rb-tree contains less packets, SACK is cheaper.
> 8) Removal of legacy code. Less maintenance hassles.
> 
> Note that I have left the sendpage/zerocopy paths, but they probably can
> benefit from the same strategy.
> 
> Thanks to Oleksandr Natalenko for reporting a performance issue for BBR/fq_codel,
> which was the main reason I worked on this patch series.

Series applied, thanks Eric.

SCTP might want to do something similar, and if so we can get rid
of sk_can_gso() too.