<div dir="ltr">I am part of the M-Lab team.<div><br></div><div>For years we published a "jitter" metric that I considered to be bogus, basically max_rtt - min_rtt, (which were builtin Web100 instruments).</div><div><br></div><div>In 2019, we transitioned from web100 to "standard" linux tcp_info, which does not capture max_rtt. Since the web100 jitter was viewed as bogus, we did not attempt to reconstruct it, although we could have. Designing and implementing a new latency metric was on my todo list from the beginning of that transition, but chronically preempted by more pressing problems.</div><div><br></div><div>It finally made it to the top of my queue which is why I am suddenly not lurking here and the new rpm list. I was very happy to see the Apple responsiveness metric, and realized that M-Lab can implement a TCP version of it, that can be computed both in real time on future tests and retroactively over archived tests collected over the last 12 years.</div><div><br></div><div>This quick paper might be of interest: <a href="https://docs.google.com/document/d/1HkeJTgwLdbbdHe0dF9SWrpr8Vt7ngnovLpdDTScuUtk/edit#heading=h.sy6m01i6oa9a" style="text-decoration-line:none"><span style="font-size:11pt;font-family:Arial;background-color:transparent;font-weight:700;font-variant-numeric:normal;font-variant-east-asian:normal;text-decoration-line:underline;vertical-align:baseline;white-space:pre-wrap">Preliminary Longitudinal Study of Internet Responsiveness</span></a></div><div>. <br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>Thanks,</div>--MM--<br>The best way to predict the future is to create it. - Alan Kay<br><br>We must not tolerate intolerance;</div><div dir="ltr"> however our response must be carefully measured: </div><div> too strong would be hypocritical and risks spiraling out of control;</div><div> too weak risks being mistaken for tacit approval.</div></div></div></div></div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Aug 9, 2021 at 5:27 PM Dave Collier-Brown <<a href="mailto:dave.collier-brown@indexexchange.com">dave.collier-brown@indexexchange.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Knowing programmers, I'd more likely assume latency when it's easiest to measure. At a guess, either</p>
<ul>
<li>average of upload or download</li><li>average of download (as it comes first)</li></ul>
<p>--dave (call me "Wally" (:-)) c-b<br>
</p>
<p><font size="-1"><br>
</font></p>
<p><font size="-1"></font>On 2021-08-09 4:24 p.m., Jonathan Morton wrote:<br>
</p>
<blockquote type="cite">
<blockquote type="cite">
<pre>On 9 Aug, 2021, at 10:25 pm, Dave Collier-Brown <a href="mailto:dave.collier-brown@indexexchange.com" target="_blank"><dave.collier-brown@indexexchange.com></a> wrote:
My run of it reported latency, but without any qualifiers...
</pre>
</blockquote>
<pre>One would reasonable assume that's idle latency, then.
- Jonathan Morton
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<pre cols="72">--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
<a href="mailto:dave.collier-brown@indexexchange.com" target="_blank">dave.collier-brown@indexexchange.com</a> | -- Mark Twain</pre>
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