148 строки
5.5 KiB
Markdown
148 строки
5.5 KiB
Markdown
iperf3: A TCP, UDP, and SCTP network bandwidth measurement tool
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================================================================
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Summary
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-------
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iperf is a tool for active measurements of the maximum achievable
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bandwidth on IP networks. It supports tuning of various parameters
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related to timing, protocols, and buffers. For each test it reports
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the bandwidth, loss, and other parameters.
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This version, sometimes referred to as iperf3, is a redesign of an
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original version developed at NLANR/DAST. iperf3 is a new
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implementation from scratch, with the goal of a smaller, simpler code
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base, and a library version of the functionality that can be used in
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other programs. iperf3 also a number of features found in other tools
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such as nuttcp and netperf, but were missing from the original iperf.
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These include, for example, a zero-copy mode and optional JSON output.
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Note that iperf3 is NOT backwards compatible with the original iperf.
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Primary development for iperf3 takes place on CentOS Linux, FreeBSD,
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and MacOS X. At this time, these are the only officially supported
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platforms, however there have been some reports of success with
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OpenBSD, Android, other Linux distributions.
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iperf3 is principally developed by ESnet / Lawrence Berkleley National
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Laboratory. It is released under a three-clause BSD license.
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For more information see: https://github.com/esnet/iperf
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Obtaining iperf3
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----------------
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Downloads of iperf3 are available at:
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http://stats.es.net/software/
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To check out the most recent code, do:
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git clone https://github.com/esnet/iperf.git
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Building iperf3
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---------------
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### Prerequisites: ###
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* libuuid: this is not installed by default for Debian/Ubuntu Systems
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to install: `apt-get install uuid-dev`
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### Building ###
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./configure; make; make install
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(Note: If configure fails, try running `./bootstrap.sh` first)
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Invoking iperf3
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---------------
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iperf3 includes a manual page listing all of the command-line options.
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The manual page is the most up-to-date reference to the various flags and parameters.
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For sample command line usage, see:
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http://fasterdata.es.net/performance-testing/network-troubleshooting-tools/iperf-and-iperf3/
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Using the default options, iperf is meant to show typical well
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designed application performance. 'Typical well designed application'
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means avoiding artificial enhancements that work only for testing
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(such as splice()'ing the data to /dev/null). iperf does also have
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flags for 'extreme best case' optimizations but they must be
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explicitly activated.
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These flags include:
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-Z, --zerocopy use a 'zero copy' sendfile() method of sending data
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-A, --affinity n/n,m set CPU affinity
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Bug Reports
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-----------
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Before submitting a bug report, try checking out the latest version of
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the code, and confirm that its not already fixed. Then submit to:
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https://github.com/esnet/iperf/issues
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Changes from iperf 2.x
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----------------------
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New options:
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-V, --verbose more detailed output than before
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-J, --json output in JSON format
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-Z, --zerocopy use a 'zero copy' sendfile() method of sending data
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-O, --omit N omit the first n seconds (to ignore slowstart)
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-T, --title str prefix every output line with this string
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-F, --file name xmit/recv the specified file
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-A, --affinity n/n,m set CPU affinity (Linux and FreeBSD only)
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-k, --blockcount #[KMG] number of blocks (packets) to transmit (instead
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of -t or -n)
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-L, --flowlabel set IPv6 flow label (Linux only)
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Changed flags:
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-C, --linux-congestion set congestion control algorithm (Linux only)
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(-Z in iperf2)
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Deprecated options:
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Not planning to support these iperf2 flags. If you really miss these
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options, please submit a request in the issue tracker:
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-d, --dualtest Do a bidirectional test simultaneously
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-r, --tradeoff Do a bidirectional test individually
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-T, --ttl time-to-live, for multicast (default 1)
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-x, --reportexclude [CDMSV] exclude C(connection) D(data) M(multicast)
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S(settings) V(server) reports
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-y, --reportstyle C report as a Comma-Separated Values
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Also deprecated is the ability to set the options via environment
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variables.
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Known Issues
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------------
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* UDP performance: iperf2/iperf3 both only are only about 50% as fast
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as nuttcp in UDP mode. We are looking into this, but in the meantime,
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if you want to get UDP above 5Gbps, we recommend using nuttcp instead
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(http://www.nuttcp.net/).
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* Interval reports on high-loss networks: The way iperf3 is currently
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implemented, the sender write command will block until the entire
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block has been written. This means that it might take several seconds
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to send a full block if the network has high loss, and the interval
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reports will have widely varying interval times. We are trying to
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determine the best solution to this, but in the meantime, try using a
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smaller block size if you get strange interval reports. For example,
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try "-l 4K".
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* The -Z flag sometimes hangs on OSX.
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* On OpenBSD, the server seems to require a "-4" argument, implying
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that it can only be used with IPv4.
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* When specifying the TCP buffer size using the "-w" flag on Linux, Linux
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doubles the value you pass in. (You can see this using iperf3's debug flag).
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But then the CWND does not actually ramp up to the doubled value, but only
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to about 75% of the doubled value. This appears to be by design.
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