Don't know but comments are ignored by the compiler ;)

Can you share your results?  I'd be curious to see the variation and if it 
could be related to things like scheduling.

Also, what os are you using?  If you are using linux you may want to set the 
processes to use SCHED_RR

http://www.cyberciti.biz/faq/howto-set-real-time-scheduling-priority-process/

I do that in iperf2

http://sourceforge.net/projects/iperf2/?source=directory

Bob
From: Jon Lederman [mailto:jonleder...@gmail.com]
Sent: Tuesday, September 02, 2014 1:29 PM
To: Bob (Robert) McMahon
Cc: iperf-users@lists.sourceforge.net
Subject: Re: [Iperf-users] Difference In Jitter Calculations Between IPerf2 and 
IPerf3

Thanks.  Look forward to your results.  Even though I also noticed that the 
calculation looks similar on the surface, I did notice a comment in iperf3 to 
the effect:

// XXX: This is NOT the way to calculate jitter
    //      J = |(R1 - S1) - (R0 - S0)| [/ number of packets, for average]

Any thoughts why that is in there?  The calculation in the code appears to have 
come directly out of the RFC 1889/3550.

Also, I want to clarify that this calculation seems to be average jitter not 
instantaneous jitter.

Thanks.

-Jon
On Sep 2, 2014, at 4:23 PM, Bob (Robert) McMahon 
<rmcma...@broadcom.com<mailto:rmcma...@broadcom.com>> wrote:


A quick cursory view of the source suggests the same calculation.  Let me run 
both on my test rig and see if I get similar results.

Bob
-----Original Message-----
From: Jon Lederman [mailto:jonleder...@gmail.com]
Sent: Monday, September 01, 2014 5:22 PM
To: iperf-users@lists.sourceforge.net<mailto:iperf-users@lists.sourceforge.net>
Subject: [Iperf-users] Difference In Jitter Calculations Between IPerf2 and 
IPerf3

Hi,

In measuring jitter using Iperf 2.0.5 and Iperf 3, I have noticed a marked 
difference in the calculations up to an order of magnitude.  Could you explain 
the differences in calculation of jitter between 2.0.5 and 3 and the accuracy.  
Which should I rely upon?

Thanks in advance.

Jon
------------------------------------------------------------------------------
Slashdot TV.
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
_______________________________________________
Iperf-users mailing list
Iperf-users@lists.sourceforge.net<mailto:Iperf-users@lists.sourceforge.net>
https://lists.sourceforge.net/lists/listinfo/iperf-users

------------------------------------------------------------------------------
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
_______________________________________________
Iperf-users mailing list
Iperf-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/iperf-users

Reply via email to