Re: [LARTC] how to get the latency down on maxed out classes? + extra question

["sufcrusher" <sufcrusher@zonnet.nl>]

> > TC_UPLINK_RATE="100"
> > TC_RATE[0]P
> > TC_CEIL[0]\x110
> So this class has ceil = 110kbit, but the parent class has ceil = 100kbit.
> The parent ceil is not respected so this class can use 110kbit if it
wants.
> I don't think this is what you want.


Oops, you're right. I had been testing it with parent rate at 110, but
obviously forgot to put it back down. Also, I presumed the parent ceil would
be respected, so thanks for the tip.

> > TC_RATE[1]\x15
> > TC_CEIL[1]`
> > TC_RATE[2]\x10
> > TC_CEIL[2]`
> > TC_RATE[3]=5
> > TC_CEIL[3]0
> There is also a drawbeck if you use prio to improve latency.  Devik did
some
> testing.  A lower prio is good for delays IF the class with the lower prio
> never sends more then it's rate (so it's never overlimited).  If it do so,
> other classes are served first and the delays will be very bad.  I haven't
> test it myself, but you can find it in the user guide of htb chapter 7
> (http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm#prio).
> You can force a class to never exceeds its rate if you use a policer in
the
> filter so packets that exceeds the rate are dropped by the filter.  But
> again, I haven't test it.

I need the low-latency class for games (CounterStrike), so I can't afford to
drop any packets (I guess). On the other hand it typically doesn't use too
much bandwidth, so it can lend the rest.

I had read devik's manual (I've read a lot on htb stuff, but I can't claim
to remember it all, let alone put it in practise) but I don't see you
statement "A lower prio is good for delays IF the class with the lower prio
never sends more then it's rate (so it's never overlimited)." in it. In
fact, it says that the higher prio class gets "excess bandwidth first",
which is what I want.

But you are probably right that my solution is way too crude for practical
purposes. Maybe I should only be using prio for the game-packets and put all
other classes in the same prio (which is also mentioned at devik's site).

Like I suspected, my current script is very basic, I need quite some more
work on it.

Anyway, thanks again Stef, you're doing a great job!

Jannes Faber

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