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Power Open Source Development

Explore the open source tools and capabilities for building and deploying modern applications on IBM Power platforms including AIX, IBM i, and Linux.


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  • 1.  iperf3 not multithreaded ?

    Posted 05/20/25 05:46 AM

    Hi there

    Could it be that iperf3 is not multithreaded like iperf2 ? We're not able to saturate a 100Gbit Adapter with iperf3 as with iperf2.

    It seems that as per Internet search iperf3 should be multithreaded.

    We test with iperf3 -s on one host and iperf3 <IP> -P 10 (10 parallel sessions)

    Any hints ? Maybe we need to use other options ?

    Thanks in advance and kind regards,

    Stefano



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    Stefano Calisto
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    #AIXOpenSource


  • 2.  RE: iperf3 not multithreaded ?

    Posted 05/20/25 06:36 AM
    Edited by Ranjit Ranjan 05/20/25 06:36 AM

    Hello,

    'iperf3 -v' output shows that threading is enabled. is iperf3 is not behaving as compared to iperf2 w.r.t mulithreading ? 

    # iperf3 -v
    iperf 3.18 (cJSON 1.7.15)
    AIX aixoss1-lp6 3 7 000336AA7A00
    Optional features available: SCTP, authentication, support IPv4 don't fragment, POSIX threads

    Thanks
    Ranjit



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    Ranjit Ranjan
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  • 3.  RE: iperf3 not multithreaded ?

    Posted 05/20/25 07:11 AM

    Hi there Ranjit

    We're not getting the expected throughput we had with iperf2. I'm curious to know if there are others who can confirm this behaviour or proof us wrong and it works as expected.


    Thanks and kind regards,


    Stefano



    ------------------------------
    Stefano Calisto
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  • 4.  RE: iperf3 not multithreaded ?

    Posted 05/21/25 03:23 AM
    Edited by Stefano Calisto 05/21/25 03:23 AM

    Hi everybody

    We found the problem. One of the test system had an old version of iperf3 installed (3.14).
    That explains why we didn't get the expected throughput.

    Thanks and kind regards,

    Stefano



    ------------------------------
    Stefano Calisto
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  • 5.  RE: iperf3 not multithreaded ?

    Posted 05/21/25 05:29 AM

    Hi,
    Glad, you found the RC. 
    Yes. iperf3 Multithreaded support is enabled from 3.16+. .https://github.com/esnet/iperf/releases/tag/3.16

    Thanks

    Ranjit



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    Ranjit Ranjan
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