84 строки
3.9 KiB
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84 строки
3.9 KiB
ReStructuredText
iperf3 FAQ
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==========
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What is the history of iperf3, and what is the difference between iperf2 and iperf3?
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iperf2 was orphaned in the late 2000s at version 2.0.5, despite some
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known bugs and issues. After spending some time trying to fix
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iperf2's problems, ESnet decided by 2010 that a new, simpler tool
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was needed, and began development of iperf3. The goal was make the
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tool as simple as possible, so others could contribute to the code
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base. For this reason, it was decided to make the tool single
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threaded, and not worry about backwards compatibility with
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iperf2. Many of the feature requests for iperf3 came from the
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perfSONAR project (http://www.perfsonar.net).
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Then in 2014, Bob (Robert) McMahon from Broadcom restarted
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development of iperf2 (See
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https://sourceforge.net/projects/iperf2/). He fixed many of the
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problems with iperf2, and added a number of new features similar to
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iperf3. iperf2.0.8, released in 2015, made iperf2 a useful tool.
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As of this writing (2017), both iperf2 and iperf3 are being actively
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(although independently) developed. We recommend being familiar with
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both tools, and use whichever tool’s features best match your needs.
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A feature comparison of iperf2, iperf3, and nuttcp is available at:
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https://fasterdata.es.net/performance-testing/network-troubleshooting-tools/throughput-tool-comparision/
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iperf3 parallel stream performance is much less than iperf2. Why?
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iperf3 is single threaded, and iperf2 is multi-threaded. We
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recommend using iperf2 for parallel streams.
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If you want to use multiple iperf3 streams use the method described `here <https://fasterdata.es.net/performance-testing/network-troubleshooting-tools/iperf/multi-stream-iperf3/>`_.
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I’m trying to use iperf3 on Windows, but having trouble. What should I do?
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iperf3 is not officially supported on Windows, but iperf2 is. We
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recommend you use iperf2.
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Some people are using Cygwin to run iperf3 in Windows, but not all
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options will work. Some community-provided binaries of iperf3 for
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Windows exist.
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I'm seeing quite a bit of unexpected UDP loss. Why?
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First, confirm you are using iperf 3.1.5 or higher. There was an
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issue with the default UDP send size that was fixed in
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3.1.5. Second, try adding the flag ``-w2M`` to increase the socket
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buffer sizes. That seems to make a big difference on some hosts.
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iperf3 UDP does not seem to work at bandwidths less than 100Kbps. Why?
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You'll need to reduce the default packet length to get UDP rates of less that 100Kbps. Try ``-l100``.
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What congestion control algorithms are supported?
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On Linux, run this command to see the available congestion control
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algorithms (note that some algorithms are packaged as kernel
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modules, which must be loaded before they can be used)::
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/sbin/sysctl net.ipv4.tcp_available_congestion_control
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I’m using the ``--logfile`` option. How do I see file output in real time?
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Use the ``--forceflush`` flag.
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Why can’t I run a UDP client with no server?
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This is potentially dangerous, and an attacker could use this for a
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denial of service attack. We don't want iperf3 to be an attack tool.
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I'm trying to use iperf3 to test a 40G/100G link...What do I need to know?
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See the following pages on fasterdata.es.net:
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- https://fasterdata.es.net/host-tuning/100g-tuning/
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- https://fasterdata.es.net/performance-testing/network-troubleshooting-tools/iperf/multi-stream-iperf3/
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I have a question regarding iperf3...what's the best way to get help?
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Searching on the Internet is a good first step.
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http://stackoverflow.com/ has a number of iperf3-related questions
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and answers, but a simple query into your favorite search engine can
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also yield some results.
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There is a mailing list nominally used for iperf3 development,
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iperf-dev@googlegroups.com.
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We discourage the use of the iperf3 issue tracker on GitHub for
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support questions. Actual bug reports, enhancement requests, or
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pull requests are encouraged, however.
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