HTB vs HFSC, HTB is highly inaccurate

HTB vs HFSC, HTB is highly inaccurate

[Denys Fedoryschenko]

Hi again

I test again HTB and HFSC, this time in very simple case.

Regarding HTB - i try without quantum, with different values, without and with 
cburst (big and small), with HZ=1000 and default, hysteresis on and off - it 
is almost same result. 

While i set limit at 57, it can reach 61. HFSC results is perfect.

Here is graph snapshopts.
http://www.nuclearcat.com/netdev/htb-problem.png
You can see points where HTB enabled. Other points if HFSC.

Scripts source is:

HTB http://www.nuclearcat.com/netdev/htb-script.txt
HFSC http://www.nuclearcat.com/netdev/hfsc-script.txt

Re: HTB vs HFSC, HTB is highly inaccurate

[Jarek Poplawski]

On 08-03-2009 19:45, Denys Fedoryschenko wrote:
> Hi again
> 
> I test again HTB and HFSC, this time in very simple case.
> 
> Regarding HTB - i try without quantum, with different values, without and with 
> cburst (big and small), with HZ=1000 and default, hysteresis on and off - it 
> is almost same result. 
> 
> While i set limit at 57, it can reach 61. HFSC results is perfect.
> 
> Here is graph snapshopts.
> http://www.nuclearcat.com/netdev/htb-problem.png
> You can see points where HTB enabled. Other points if HFSC.

Very nice picture, but some tc snapshot stats for qdisc and classes
would be appreciated.

> 
> Scripts source is:
> 
> HTB http://www.nuclearcat.com/netdev/htb-script.txt

| echo "class add dev eth0.37 parent 1:1 classid 1:2 htb rate 40Mbit ceil 56Mbit burst 16000b cburst 16000b quantum 16000"
| echo "class add dev eth0.37 parent 1:1 classid 1:3 htb rate 26Mbit ceil 56Mbit burst 16000b cburst 16000b quantum 16000"

I guess you should try with rates 40/16 or 30/26 here.

BTW, it doesn't matter here, but for various reasons it's better to
add classes before filters pointing these classes.

> HFSC http://www.nuclearcat.com/netdev/hfsc-script.txt

This link doesn't work for me.

Jarek P.

Re: HTB vs HFSC, HTB is highly inaccurate

[Denys Fedoryschenko]

On Monday 09 March 2009 10:07:00 Jarek Poplawski wrote:
> I guess you should try with rates 40/16 or 30/26 here.
Seems i was blind. I forgot main HTB rule - always keep sum or childs rate 
less than parent. And i should not listen my boss, cause he dont know 
arithmetics. (i ask him about decision, how much for what :-D ).

I will try some experiments now.

But at same time HFSC worked fine.
File fixed.

>
> BTW, it doesn't matter here, but for various reasons it's better to
> add classes before filters pointing these classes.
>
> > HFSC http://www.nuclearcat.com/netdev/hfsc-script.txt
>
> This link doesn't work for me.
>
> Jarek P.
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