[Bloat] debloats/day metric?

[Pete Heist]

> On Aug 27, 2018, at 10:02 AM, Jonathan Morton <chromatix99 at gmail.com> wrote:
> 
>> On 27 Aug, 2018, at 10:44 am, Pete Heist <pete at heistp.net> wrote:
>> 
>> …request pairs, one given strict priority at the bottleneck and one best effort, then measure the difference between the two (for both RTT and OWD).
>> 
>> Assuming this yields useful data…
> 
> For the overwhelming majority of bloated bottlenecks, it will not - because they have zero concept of "strict priority".


To clarify, I control the bottleneck link and would give that priority with tc for a chosen dscp marking, then use that marking in one of the two requests in the pair. That would be required to make this measurement. I realize there are other areas in the stack though where I can’t give priority that may sufficiently pollute the results.

But, as a rough illustration, attached are two flent rrul_be runs with and without cake on my home connection (p2p WiFi with an airOS device). In the plot without cake, it’s pretty clear that ICMP is being prioritized, as its RTT stays relatively stable under load, while UDP RTT increases. (I believe this prioritization happens when airMAX is enabled in airOS, because when it’s disabled, ICMP and UDP RTTs under load are almost identical.)

Presumably, the difference between the two RTTs would approximate bloat. Or if not, why not? And presumably, I could create a similar effect by giving priority to one of two requests in a pair...

Pete


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