Re: [PATCH v6 net-next 2/2] tcp: Add Redundant Data Bundling (RDB)

Eric Dumazet
2016-03-14T21:15:43Z

On Thu, 2016-03-03 at 19:06 +0100, Bendik Rønning Opstad wrote:
> Redundant Data Bundling (RDB) is a mechanism for TCP aimed at reducing
> the latency for applications sending time-dependent data.
>
> Latency-sensitive applications or services, such as online games,
> remote control systems, and VoIP, produce traffic with thin-stream
> characteristics, characterized by small packets and relatively high
> inter-transmission times (ITT). When experiencing packet loss, such
> latency-sensitive applications are heavily penalized by the need to
> retransmit lost packets, which increases the latency by a minimum of
> one RTT for the lost packet. Packets coming after a lost packet are
> held back due to head-of-line blocking, causing increased delays for
> all data segments until the lost packet has been retransmitted.

Acked-by: Eric Dumazet <edumazet@google.com>

Note that RDB probably should get some SNMP counters,
so that we get an idea of how many times a loss could be repaired.

Ideally, if the path happens to be lossless, all these pro active
bundles are overhead. Might be useful to make RDB conditional to
tp->total_retrans or something.