Re: Incorrect Throughput Summaries in UDP?


On Thu, 27 Feb 2003, Kevin Gibbs wrote:

> What operating system are you using? It would appear that iperf did not 
> find a 64bit integer to use as the total amount of traffic. As such you 
> overflowed your 32bit integer at 4GB. 

linux 7.2 - i compiled from source - is there a compile flag i should set?

Thanks,

Yee.

> 
> Kevin
> 
> On Thu, 27 Feb 2003, Yee-Ting Li wrote:
> 
> > Hello,
> > 
> > We're trying to do some iperf tests through an uncongested network using UDP 
> > streams, reporting the rate every 2 seconds for 1 minute. We're using iperf 
> > 1.6.5 with pthreads and we get some strange reporting of the summary result:
> > 
> > 
> > ------------------------------------------------------------
> > Server listening on UDP port 5010
> > Receiving 1472 byte datagrams
> > UDP buffer size: 2097152 Byte (WARNING: requested 1048576 Byte)
> > ------------------------------------------------------------
> > [  3] local xxx.xxx.xxx.xxx port 5010 connected with 
> > xxx.xxx.xxx.xxx port 32769
> > [ ID] Interval       Transfer     Bandwidth       Jitter   Lost/Total 
> > Datagrams
> > [  3]  0.0- 2.0 sec  204248832 Bytes  816993694 bits/sec  0.015 ms 
> > 41676/180432 (23%)
> ...
> > [  3] 58.0-60.0 sec  197239168 Bytes  788955489 bits/sec  0.012 ms 
> > 47441/181435 (26%)
> > [  3]  0.0-60.0 sec  1559126656 Bytes  207849079 bits/sec  0.012 ms 
> > 1466661/5443627 (27%)
> > [  3]  0.0-60.0 sec  2 datagrams received out-of-order
> > 
> > 
> > 
> > As you can see, the summary rate is much smaller than that reported by the 
> > regular intervals; also, the total number of bytes transfered is about a third 
> > less than the accumulated count.
> > 
> > We repeated the test a few times and the report is similar in all tests.
> > 
> > 
> > Any comments/suggestions appreciated!
> > 
> > Yee.
> > 
> > 
> > 
> > 
> 

-- 
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 Yee-Ting Li                                    email: ytl --at-- hep.ucl.ac.uk
 High Energy Particle Physics              http://www.hep.ucl.ac.uk/~ytl
 University College London                     Tel: +44 (0) 20 7679 1376
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