nquiry on iperf3 performance behavior

[yunkicho80]

Hello,
I am currently using iperf3 version 3.9 (cHSON 1.7.13).
To perform bidirectional performance testing, I run tests with the -P 8 --bidir options. However, I’ve noticed that sometimes the performance is good, while other times it drops significantly.
The test environment is VMware-based, running Rocky Linux 9.5, and the network NIC bandwidth is 25G.
Could there be cases where performance fluctuates or drops intermittently in version 3.9?
Thanks.
when performance is good

when performance is not good

[davidBar-On]

I don't know if this is related, but PR #1011 fixed an issue related to 100% CPU usage when --bidir is used, so suggest to use a new version of iperf3 (version 3.9 is quite old). (By the way, you opened the same issue also as #1937 which should probably be closed.)