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

[Eric Dumazet]

On Wed, 2015-04-22 at 17:59 +0200, Steinar H. Gunderson wrote:
> On Wed, Apr 22, 2015 at 03:26:27PM +0000, luca.muscariello at orange.com wrote:
> > BTW if a paced flow from Google shares a bloated buffer with a non paced
> > flow from a non Google server,  doesn't this turn out to be a performance
> > penalty for the paced flow?
> 
> Nope. The paced flow puts less strain on the buffer (and hooray for that),
> which is a win no matter if the buffer is contended or not.
> 
> > fq_codel gives incentives to do pacing but if it's not deployed what's the
> > performance gain of using pacing?
> 
> fq_codel doesn't give any specific incentive to do pacing. In fact, if
> absolutely all devices on your path would use fq_codel and have adequate
> buffers, I believe pacing would be largely a no-op.

While this might be true for stationary flows (ACK driven, no pacing is
enforced in sch_fq), sch_fq/pacing is still nice after idle period.

Say a flow deliver chunks of data. With pacing, you no longer have to
slow start after idle.