Receiver Results Empty

[pricey123]

Context

I am using iPerf to test the connection between two servers, when doing so I receive no receiver results (Reverse) or sender results (normal).
Why does client show both set of results but the server only displays on set?
iPerf Server Results.txt
iPerf Client Results.txt

• Version of iperf3:
  iPerf 3.1.7 both servers.

• Hardware:
  These are machines from AWS I am using to test from work. These are t2.micro servers with the below OS.

• Operating system (and distribution, if any):
  RHEL-7.5_HVM_GA-20180322-x86_64-1-Hourly2-GP2 (ami-7c1bfd1b)

• Other relevant information (for example, non-default compilers,
  libraries, cross-compiling, etc.):
  All traffic is allowed between the two servers.
  Installed using YUM.

Bug Report

I am not seeing any receiver results if put in reverse mode or sender results if in normal.
I used the below commands.
iperf3 -s -p 24002 -V
iperf3 -c -R -i 1 -V -p 24002 -P 5

• Expected Behavior
  I should be seeing results for both sender / receiver.

• Actual Behavior
  Am only seeing results for receiver if run in reverse mode or sender if normal.

• Steps to Reproduce
  Install iPerf, and run a standard iPerf test between the two.

[bmah888]

This is due to a long-standing design shortcoming in iperf3. Basically, the server side cannot print summary statistics from the client due to the ordering of messages on the control channel. Newer versions of iperf3 (starting around 3.2) make this a little better by not being outright misleading in the summary statistics (see #562), but don't really solve the main problem. Still you might try using a newer version of iperf3 (3.5 is current as of this writing).

#584 is related to this as well, or rather a solution that solves this problem should also try to solve #584 as well.

I'm not sure what to do about this exactly since we'd need to revisit the state machines and the control messages.

[pricey123]

Would the results shown on the client side machine show the same results that would be shown on the server? If so would you suggest taking these. We use iPerf in the company we work for to validate connections so need to ensure that we get the most accurate results we can.

[bmah888]

Yes, if the server were able to display the statistics for both ends of the connection, it would show the same results that the client shows. So yes if you have access to the client's output, that should give you the desired results.

[akiarie]

@bmah888 I'm dealing with the same problem, not sure I understand what you mean though; the results show fine without the -J flag, so what does it have to do with the server side?