netdev - Re: [PATCH linux-4.19.y 0/2] tcp_bbr: Improving TCP BBR performance for WiFi and cellular networks

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Date:   Fri, 25 Sep 2020 12:57:29 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Priyaranjan Jha <priyarjha.kernel@...il.com>
Cc:     David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
        Priyaranjan Jha <priyarjha@...gle.com>
Subject: Re: [PATCH linux-4.19.y 0/2] tcp_bbr: Improving TCP BBR performance
 for WiFi and cellular networks

On Tue, Sep 22, 2020 at 12:27:33PM -0700, Priyaranjan Jha wrote:
> From: Priyaranjan Jha <priyarjha@...gle.com>
> 
> Ack aggregation is quite prevalent with wifi, cellular and cable modem
> link tchnologies, ACK decimation in middleboxes, and common offloading
> techniques such as TSO and GRO, at end hosts. Previously, BBR was often
> cwnd-limited in the presence of severe ACK aggregation, which resulted in
> low throughput due to insufficient data in flight.
> 
> To achieve good throughput for wifi and other paths with aggregation, this
> patch series implements an ACK aggregation estimator for BBR, which
> estimates the maximum recent degree of ACK aggregation and adapts cwnd
> based on it. The algorithm is further described by the following
> presentation:
> https://datatracker.ietf.org/meeting/101/materials/slides-101-iccrg-an-update-on-bbr-work-at-google-00
> 
> (1) A preparatory patch, which refactors bbr_target_cwnd for generic
>     inflight provisioning.
> 
> (2) Implements BBR ack aggregation estimator and adapts cwnd based
>     on measured degree of ACK aggregation.

Both now queued up, thanks.

greg k-h