UDP reverse mode doesn't output sensible data

[bmah888]

From intra2net on November 19, 2013 07:59:00

What steps will reproduce the problem? 1. recompile the 3.0 code as published on the website
2. on the server run: iperf3 --server
3. on the client run: iperf3 -c -V -R -u What is the expected output? What do you see instead? Expected: 10 seconds continous transfer from server to client

I always get only transfer for the first second:

[root@intratest132 ~]# iperf3 -c 172.16.1.133 -V -R -u
iperf version 3.0-RC5 (07 November 2013)
Linux intratest132.net.lan 3.4.51-1.i2n.i686.PAE #1 SMP Fri Jun 28 13:49:25 UTC 2013 i686 i686 i386 GNU/Linux
Time: Tue, 19 Nov 2013 23:47:54 GMT
Connecting to host 172.16.1.133, port 5201
Reverse mode, remote host 172.16.1.133 is sending
Cookie: intratest132.net.lan.1384904874.4978
[ 4] local 172.16.1.132 port 50775 connected to 172.16.1.133 port 5201
Starting Test: protocol: UDP, 1 streams, 8192 byte blocks, omitting 0 seconds, 10 second test
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 8.00 KBytes 65.5 Kbits/sec
[ 4] 1.00-2.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 2.00-3.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 3.00-4.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 4.00-5.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 5.00-6.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 6.00-7.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 7.00-8.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 8.00-9.00 sec 0.00 Bytes 0.00 bits/sec
[ 4] 9.00-10.00 sec 0.00 Bytes 0.00 bits/sec

---

Test Complete. Summary Results:
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 4] 0.00-10.00 sec 8.00 KBytes 6.55 Kbits/sec 34940.621 ms 0/1 (0%)
[ 4] Sent 1 datagrams
CPU Utilization: local/receiver 99.6%, remote/sender 68.3%

iperf Done. What version of the product are you using? On what operating system? recompiled from the published 3.0.tar.gz
32bit linux without ipv6 on both machines.

Original issue: http://code.google.com/p/iperf/issues/detail?id=112

[bmah888]

From CharlesAShaw1 on November 21, 2013 16:20:04

Something 'not right with your set-up; works for me (on a pair of HP ProBook 8470w running Ubuntu 12.04, patched with 'send-to-self'; connected back-to-back via the motherboard ethernet port).

./iperf3 -c 192.168.3.5 -V -R -u
iperf version 3.0-RC5 (07 November 2013)
Linux HP-Lab1 3.2.51-send2self #1 SMP Tue Nov 12 11:45:32 GMT 2013 x86_64 x86_64 x86_64 GNU/Linux
Time: Fri, 22 Nov 2013 00:12:57 GMT
Connecting to host 192.168.3.5, port 5201
Reverse mode, remote host 192.168.3.5 is sending
Cookie: HP-Lab1.1385079177.043596.3265039e3e
[ 4] local 192.168.3.1 port 52838 connected to 192.168.3.5 port 5201
Starting Test: protocol: UDP, 1 streams, 8192 byte blocks, omitting 0 seconds, 10 second test
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 136 KBytes 1.11 Mbits/sec
[ 4] 1.00-2.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 2.00-3.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 3.00-4.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 4.00-5.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 5.00-6.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 6.00-7.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 7.00-8.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 8.00-9.00 sec 128 KBytes 1.05 Mbits/sec
[ 4] 9.00-10.00 sec 128 KBytes 1.05 Mbits/sec

---

Test Complete. Summary Results:
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 4] 0.00-10.00 sec 1.26 MBytes 1.06 Mbits/sec 0.011 ms 0/161 (0%)
[ 4] Sent 161 datagrams
CPU Utilization: local/receiver 99.3%, remote/sender 14.4%

iperf Done.

[bmah888]

From jef.poskanzer on November 25, 2013 11:11:31

I've gotten this in TCP mode too, when using a -b bandwidth throttle. UDP uses a throttle by default, so I'm guessing the problem is in the throttling/timer code, probably on the server side, and not UDP related. Will look into it.

[bmah888]

From jef.poskanzer on November 26, 2013 15:15:20

Status: Fixed