RE: [LARTC] Extremely inaccurate results using either TBF or HTB

["Dan Farino" <DFarino@Stamps.com>]

Stef,

I solved my problem by changing PSCHED_CLOCK_SOURCE to PSCHED_CPU in
/usr/src/linux/include/net/pkt_sched.h

My graph is now a nice smooth diagonal line as I increase the bandwidth
in increments as I did before.

Thanks for you help on this one. You site has been a tremendous help in
getting me up and running.

Take care,

Dan Farino
Sr. System Engineer
Stamps.com, Inc.
Santa Monica, CA


-----Original Message-----
From: Stef Coene [mailto:stef.coene@docum.org] 
Sent: Tuesday, November 12, 2002 10:07 AM
To: Dan Farino; lartc@mailman.ds9a.nl
Subject: Re: [LARTC] Extremely inaccurate results using either TBF or
HTB

On Tuesday 12 November 2002 17:58, Dan Farino wrote:
> Hi Stef,
>
> Thanks for the reply! However, I think the gap is way too large to be
> explained by overhead, etc.
>
> Here are the results from some other tests. I started with:
> tc qdisc add dev eth2 root tbf rate 1.9mbit buffer 20Kb/8 limit 15Kb
>
> Here are the average transfer rates measured over approx 20 seconds
> (again according to PerfMon) as I change the "1.9mbit" to other values
> while performing a large download:
>
> Mbit	Kb/s
> -----	------
> 2.5	360
> 2.0	360
> 1.9	360
> 1.8	240
> 1.5	240
> 1.4	240
> 1.3	180
> 1.2	180
>
> The lines really are that flat. There is nothing resembling the graphs
> on your site. Mine has the low-res, stair-step effect that you can see
> by graphing the above numbers.
>
> I can't seem to find any "mbit" number that will actually produce a
cap
> at exactly 2mbit.
>
> I will try a both different type NIC and Debian at some point today.
What NIC are you using ?

> Thanks for your help!
No problem.  I can send you my scripts that I use the record the
bandwidth 
usage.  Some of them can be found on www.docum.org.  Basically, I create
a 
iptables chain for each traffic stream I want to monitor.  I record the 
counters each second and calculates the bandwdith.  
I have some scripts that executes a htb script, starts the needed flows,

calculates the bandwidth, if the bandwidth is stable : record the
bandwidth, 
restart the proces with a different setting.
After some time, you have it for each rate so you can create a nice
graph.


Stef

-- 

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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