[Bloat] benefits of ack filtering

[Luca Muscariello]

Did you check RFC 3449 ?
https://tools.ietf.org/html/rfc3449#section-5.2.1

It would be interesting to know what is the minimum ACK rate to achieve
full utilisation.
Or the how the downlink rate depends on the uplink ACK rate.
I'm sure I've seen this dependency in some old paper.


On Wed, Nov 29, 2017 at 1:49 PM, Mikael Abrahamsson <swmike at swm.pp.se>
wrote:

> On Wed, 29 Nov 2017, Sebastian Moeller wrote:
>
> Well, ACK filtering/thinning is a simple trade-off: redundancy versus
>> bandwidth. Since the RFCs say a receiver should acknoledge every second
>> full MSS I think the decision whether to filter or not should be kept to
>>
>
> Why does it say to do this? What benefit is there to either end system to
> send 35kPPS of ACKs in order to facilitate a 100 megabyte/s of TCP transfer?
>
> Sounds like a lot of useless interrupts and handling by the stack, apart
> from offloading it to the NIC to do a lot of handling of these mostly
> useless packets so the CPU doesn't have to do it.
>
> Why isn't 1kPPS of ACKs sufficient for most usecases?
>
>
> --
> Mikael Abrahamsson    email: swmike at swm.pp.se
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