[Bloat] Flow offload's impact on bufferbloat

[Mikael Abrahamsson]

On Fri, 10 Aug 2018, Rosen Penev wrote:

> My question is not really how to fix it. I already know that. I just
> got the feeling that bypassing parts of the linux network stack would
> result in less buffering.

On the OpenWrt configuration page for the "software flow offload":

"Experimental feature. Not fully compatible with QoS/SQM."

I don't know exactly what it does, it reduces amount of CPU cycles needed 
to forward packets in an already established flow it seems, but I'd 
imagine that it might very well bypass some of the scheduling code which 
could explain what you're seeing. So you might get faster forwarding but 
less AQM.

So if your device isn't fast enough to keep up with your total Internet 
access speed, then this might be a good thing. If your device is faster 
than what's needed, then you'd better spend the cycles on getting good AQM 
instead of freeing up more CPU that isn't used for anything anyway.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se