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<div class="moz-cite-prefix">I suspect you're seeing a decrease in
the speed of data into a sink, not a decrease in end-to-end speed.
Measurement results can often be puzzling here (;-))<br>
<br>
My description of the situation is:<br>
<br>
- an infinite (or just bloatily large) queue will accept data at
just about any rate you offer it, and keep it around until the
service centre can process it, which is in our case is the other
end of the network link getting it. If the queue only reports
ingress, it will show really large values, sometimes well above
what the link can ever handle. (Some folks report those rates as
a marketing feature. I'm not sure that's exactly kosher (;-))<br>
<br>
- a queue processes the same amount of data per unit time when
latency is at a minimum as it does when it's at a maximum, so
normal queues should be tuned for minimum latency.<br>
<br>
- in TCP, there is a cost in retransmissions when we use drops to
signal the sender that they've sent too much, so it's best to keep
your rate just below the rate at which you get drops. That
maximizes throughput for a given small latency. TCP does this
automatically when not bloatified, and on average stays really
really close to the maximum speed of the channel.<br>
<br>
- buffers are really good to smooth out brief stoppages or bursty
senders, but have to be kept nearly empty to be able to do that,
and then drained quickly when they get filled.<br>
<br>
--dave (processing an email queue while waiting for a compile) c-b<br>
<br>
<br>
On 17/08/16 04:21 AM, Alec Robertson wrote:<br>
</div>
<blockquote
cite="mid:CAGwEnGxMt3XUpqUxk80Pdqkd1pfX42BMc3AQ1zXsSGUAZjmkJQ@mail.gmail.com"
type="cite">
<div dir="ltr">I'm on a TalkTalk FTTC connection in the UK, with a
sync speed of 58976Kbps, via a Billion 8800NL in bridge mode to
my TP-LINK Archer C7 (currently running LEDE r1348) with
sqm-scripts 1.0.7-1 and
mod-sched-cake 4.4.15+2016-06-29-747..5-1.
<div><br>
</div>
<div>I have selected cake as the qdisc and piece_of_cake.qos as
the queue setup script.</div>
<div><br>
</div>
<div>I've managed to get bufferbloat under control, with only
3-4ms of added ping when downloading but I've had to set the
ingress to 43000, reducing my speed not hugely but more than I
might have expected.</div>
<div><br>
</div>
<div>On the upload side I'm syncing at 10422Kbps and the egress
is set to 9300, so not quite as bad. Bufferbloat here is also
under control, at maybe 2-3ms when downloading.</div>
<div><br>
</div>
<div>Is there anything I can do to reclaim more of the download
speed? How can I diagnose this?</div>
<div><br>
</div>
<div>The other question I would like to ask is, what's the
absolute best way to see what the ping maximum actually is?
With <a moz-do-not-send="true" href="http://speedtest.net">speedtest.net</a>
the ping only increases 1-2ms (pinging <a
moz-do-not-send="true" href="http://bbc.co.uk">bbc.co.uk</a>)
and the same is true for <a moz-do-not-send="true"
href="http://dslreports.com">dslreports.com</a> (maybe a
little bit higher, maximum of about 5ms) but on the <a
moz-do-not-send="true" href="http://dslreports.com">dslreports.com</a>
site it says 9ms+ at times?</div>
<div><br>
</div>
<div>Thanks.<br clear="all">
<div>
<div class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<h1 style="margin:0px 0px 8px;padding:0px 0px 0px
15px;border:0px;font-family:Arial,Helvetica,sans-senif,SimSun,宋体;font-size:18px;font-weight:400;line-height:22px;vertical-align:baseline;color:rgb(51,51,51)"><span
style="color:rgb(73,79,80);font-family:"Helvetica
Neue",san-serif;font-size:14px;line-height:21px">--</span><br
style="color:rgb(73,79,80);font-family:"Helvetica
Neue",san-serif;font-size:14px;line-height:21px">
<span
style="color:rgb(73,79,80);font-family:"Helvetica
Neue",san-serif;font-size:14px;line-height:21px">Alec Robertson</span><br>
</h1>
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<pre wrap="">_______________________________________________
Bloat mailing list
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<a class="moz-txt-link-freetext" href="https://lists.bufferbloat.net/listinfo/bloat">https://lists.bufferbloat.net/listinfo/bloat</a>
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<br>
<p><br>
</p>
<br>
<pre class="moz-signature" cols="72">--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
<a class="moz-txt-link-abbreviated" href="mailto:davecb@spamcop.net">davecb@spamcop.net</a> | -- Mark Twain
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