[Bloat] DSLReports Speed Test has latency measurement built-in

[Eric Dumazet]

On Wed, 2015-04-22 at 19:28 +0200, MUSCARIELLO Luca IMT/OLN wrote:
> On 04/22/2015 07:16 PM, Eric Dumazet wrote:

> >
> > sch_fq adds *pacing*, which in itself has benefits, regardless of fair
> > queues : Smaller bursts, less self inflicted drops.
> 
> This I understand. But it can't protect from non self inflicted drops.

It really does.

This is why we deployed sch_fq and let our competitors find this later.

> 
> >
> > If flows are competing, this is the role of Congestion Control module,
> > not packet schedulers / AQM.
> 
> Exactly. Two same CC modules competing on the same link, one w pacing 
> the other one w/o pacing.
> The latter will have negative impact on the former in FIFO. Not in FQ 
> (fq_codel to clarify).

Not on modern linux kernels, thanks to TCP Small Queues.

> And that's my incentive argument which comes from the flow isolation 
> feature of FQ (_codel).

fq_codel is not something you can deploy on the backbone routers, for
known reasons.

sch_fq is something you can deploy on hosts, where the codel part is
irrelevant anyway (because of TCP Small Queues in modern linux kernels)