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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Just an FYI for those who might be interested. We added RTT and CWND samples in
<a href="https://sourceforge.net/projects/iperf2/">iperf 2.0.8</a> for the TCP transmitter (iperf client) as well as UDP mean/min/max/stdev in the iperf server (assumes the clocks are synched.) Also, much faster sampling is supported. These may be helpful
to those trying to improve wi-fi performance. To get the output one needs to use the –e option. Also, RTT/CWND is linux only. Apple is evaluating the change set and *<b>may</b>* ship it with future phones and Mac OS X systems.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Full change set here:<o:p></o:p></p>
<ul type="disc">
<li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Fix portability, compile and tested with Linux, Win10, Win7, WinXP, MacOS and Android<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Require -u for UDP (-b no longer defaults to UDP)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Improved performance<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Enhanced reporting with -e<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support smaller report intervals (5 ms or greater)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support SO_RCVTIMEOUT for server reports regardless of no packets<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Server will close the socket after no received traffic per the -t value (default is 10 sec)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support SO_TIMESTAMP for kernel level packet timestamping<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support end/end latency in mean/min/max/stdev format (UDP) (-e required)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">(assumes client and server clocks synched, e.g by Precision Time Protocol)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Add local port to bind support (-B option) using colon as separator<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">(e.g. iperf -c 192.168.100.100 -B 192.168.100.10:6001)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support TCP rate limited streams (via the -b) using token bucket<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support packets per second (UDP) via pps as units, (e.g. -b 1000pps)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Display PPS in both client and server reports (UDP) (-e required)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support realtime scheduler as a command line option (--realtime or -z, assumes proper user privileges)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Improve client tx code path so actual tx offered rate will converge to the -b value<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Improve accuracy of microsecond delay calls (in platform independent manner)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">(Use of Kalman filter to predict delay errors and adjust delays per predicted error)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Display target loop time in initial client header (UDP)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Fix final latency report sent from server to client (UDP)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Include standard deviation in latency output<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Suppress unrealistic latency output using (-/-/-/-)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Support SO_SNDTIMEO on send so socket write won't block beyond -t (TCP)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Use clock_gettime if available (preferred over gettimeofday())<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">TCP write and error counts (TCP retries and CWND for linux) (-e required)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">TCP read count, TCP read histogram (8 bins) (-e required)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"">TCP RTT and CWND values in client reports (-e required, Linux only, RTT units microseconds)<o:p></o:p></span></li></ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Bob McMahon<o:p></o:p></p>
<p class="MsoNormal">Broadcom Wi-Fi QA Engineer <o:p></o:p></p>
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