Re: [PATCH] netem: fix rate extension and drop accounting

On Wed, 2012-07-04 at 18:51 +0200, Hagen Paul Pfeifer wrote:

OK, I will work on it tomorrow! But Eric, keep in mind that this accumulative
behavior is intended: think about a hypothetical satellite link with a
bandwidth (rate) of 1000 byte/s. If you send three 1000 byte consecutively
packets. The first packet is delayed for 1 second, the second then is
transmitted after 2 seconds, the third after three seconds and so on. So
_this_ accumulative behavior is correct. Anyway, I will look at this tomorrow!

I fear you did your tests with no delay on netem.

Try to setup a rate of 100kbit and a delay of 100ms and to really get
full bandwith (100kbit), I am afraid it doesnt work.

Your algo is OK only if no packets are in queue (obviously)

But if you have 2 or 3 packets, the delay are cumulative,
but the delay should be a fixed bias for each packet.

Thanks Eric!

PS: one last question: what do you want to test? TBF and netem rate at the
same time looks, mmhh, special ... ;-) I ask myself what link exhibit this
characteristic?

TBF as a netem child was the usual way to have delay + rate before your
patch ?

Not sure why you find it special ?