Congestion Avoidance Monitoring Tools

Congestion Avoidance Monitoring Tools

[Piet Delaney]

I'm upgrading our 2.6.12 kernel to 2.6.13, which includes significant
congestion avoidance code additions and changes. I was wondering if
there are any tools folks can recommend for testing the kernel to make
sure the congestion avoidance code is operating correctly. For 
example the displaying of the congestion window as a function of time
while undergoing convergence. For causing congestion I could modify 
a kernel to discard packets once in a while on a lab gateway and hit 
it with iperf. HP's netperf looks interesting. 

Any suggestions?


-piet

-- 
---
piet@bluelane.com

Re: Congestion Avoidance Monitoring Tools

[Tom Young]

On Thu, 2006-04-20 at 22:26 -0700, Piet Delaney wrote:
> I'm upgrading our 2.6.12 kernel to 2.6.13, which includes significant
> congestion avoidance code additions and changes. I was wondering if
> there are any tools folks can recommend for testing the kernel to make
> sure the congestion avoidance code is operating correctly. For 
> example the displaying of the congestion window as a function of time
> while undergoing convergence. For causing congestion I could modify 
> a kernel to discard packets once in a while on a lab gateway and hit 
> it with iperf. HP's netperf looks interesting. 
> 
> Any suggestions?
> 
> 
> -piet
> 

Hi,

Try having a look at the output of 'ss -i' (you may need to update to
the latest iproute2 tools). You could either try and parse the text
output of that or use the same inet_diag interface that ss uses to poll
for the data it at regular intervals.

-- 
Thomas Young
http://cubinlab.ee.unimelb.edu.au/~tyo/
Research Assistant
CUBIN Research Centre - University of Melbourne

Re: Congestion Avoidance Monitoring Tools

[Andi Kleen]

On Friday 21 April 2006 07:59, Tom Young wrote:
> On Thu, 2006-04-20 at 22:26 -0700, Piet Delaney wrote:
> > I'm upgrading our 2.6.12 kernel to 2.6.13, which includes significant
> > congestion avoidance code additions and changes. I was wondering if
> > there are any tools folks can recommend for testing the kernel to make
> > sure the congestion avoidance code is operating correctly. For 
> > example the displaying of the congestion window as a function of time
> > while undergoing convergence. For causing congestion I could modify 
> > a kernel to discard packets once in a while on a lab gateway and hit 
> > it with iperf. HP's netperf looks interesting. 
> > 
> > Any suggestions?
> > 
> > 
> > -piet
> > 
> 
> Hi,
> 
> Try having a look at the output of 'ss -i' (you may need to update to
> the latest iproute2 tools). You could either try and parse the text
> output of that or use the same inet_diag interface that ss uses to poll
> for the data it at regular intervals.

Another way is to use tcptrace on a tcpdump file
(http://jarok.cs.ohiou.edu/software/tcptrace/) 
It finds a lot of statistics about the dumped TCP connections.

Newer ethereal also has some TCP plotting functions that are useful.
They don't display the congestion window directly, but you can see it indirectly.

-Andi

Re: Congestion Avoidance Monitoring Tools

[Piet Delaney]

On Fri, 2006-04-21 at 08:57 +0200, Andi Kleen wrote:
> On Friday 21 April 2006 07:59, Tom Young wrote:
> > On Thu, 2006-04-20 at 22:26 -0700, Piet Delaney wrote:
> > > I'm upgrading our 2.6.12 kernel to 2.6.13, which includes significant
> > > congestion avoidance code additions and changes. I was wondering if
> > > there are any tools folks can recommend for testing the kernel to make
> > > sure the congestion avoidance code is operating correctly. For 
> > > example the displaying of the congestion window as a function of time
> > > while undergoing convergence. For causing congestion I could modify 
> > > a kernel to discard packets once in a while on a lab gateway and hit 
> > > it with iperf. HP's netperf looks interesting. 
> > > 
> > > Any suggestions?
> > > 
> > > 
> > > -piet
> > > 
> > 
> > Hi,
> > 
> > Try having a look at the output of 'ss -i' (you may need to update to
> > the latest iproute2 tools). You could either try and parse the text
> > output of that or use the same inet_diag interface that ss uses to poll
> > for the data it at regular intervals.
> 
> Another way is to use tcptrace on a tcpdump file
> (http://jarok.cs.ohiou.edu/software/tcptrace/) 
> It finds a lot of statistics about the dumped TCP connections.

Tcptrace looks pretty good, graphing the sequence numbers as a function
of time was one of the features I'm looking for.

> 
> Newer ethereal also has some TCP plotting functions that are useful.
> They don't display the congestion window directly, but you can see it indirectly.

I never tried the ethereal graph facility, looks like another great
idea.


Thanks,
-piet

> 
> -Andi
-- 
---
piet@bluelane.com

Re: Congestion Avoidance Monitoring Tools

[Stephen Hemminger]

On Thu, 20 Apr 2006 22:26:14 -0700
Piet Delaney <piet@bluelane.com> wrote:

> I'm upgrading our 2.6.12 kernel to 2.6.13, which includes significant
> congestion avoidance code additions and changes. I was wondering if
> there are any tools folks can recommend for testing the kernel to make
> sure the congestion avoidance code is operating correctly. For 
> example the displaying of the congestion window as a function of time
> while undergoing convergence. For causing congestion I could modify 
> a kernel to discard packets once in a while on a lab gateway and hit 
> it with iperf. HP's netperf looks interesting. 
> 
> Any suggestions?
> 
> 
> -piet
> 

2.6.13 still had lots of problems, things didn't really get working
right till 2.6.15 or later. Especially with TSO.

I have a tool using kprobe's see http://developer.osdl.org/shemminger/prototypes/tcpprobe.tar.gz
I try to keep it up to date with current kernel and build process, last used it
on 2.6.16.

Re: Congestion Avoidance Monitoring Tools

[Hagen Paul Pfeifer]

* Stephen Hemminger | 2006-04-21 08:19:17 [-0700]:

>2.6.13 still had lots of problems, things didn't really get working
>right till 2.6.15 or later. Especially with TSO.

--verbose?

>I have a tool using kprobe's see http://developer.osdl.org/shemminger/prototypes/tcpprobe.tar.gz
>I try to keep it up to date with current kernel and build process, last used it
>on 2.6.16.

wget http://developer.osdl.org/shemminger/prototypes/tcpprobe.tar.gz

Ended with following error code: ;-)

00:32:48 ERROR 403: Forbidden.

HGN

-- 
Microsoft is to software what McDonalds is to gourmet cooking.

Re: Congestion Avoidance Monitoring Tools

[Stephen Hemminger]

On Mon, 24 Apr 2006 00:52:35 +0200
Hagen Paul Pfeifer <hagen@jauu.net> wrote:

> * Stephen Hemminger | 2006-04-21 08:19:17 [-0700]:
> 
> >2.6.13 still had lots of problems, things didn't really get working
> >right till 2.6.15 or later. Especially with TSO.
> 
> --verbose?
> 
> >I have a tool using kprobe's see http://developer.osdl.org/shemminger/prototypes/tcpprobe.tar.gz
> >I try to keep it up to date with current kernel and build process, last used it
> >on 2.6.16.
> 
> wget http://developer.osdl.org/shemminger/prototypes/tcpprobe.tar.gz
> 
> Ended with following error code: ;-)
> 
> 00:32:48 ERROR 403: Forbidden.
> 
> HGN
> 

Fixed