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<p>On 2020-08-09 5:35 p.m., Jonathan Morton wrote:<br>
</p>
<blockquote type="cite"
cite="mid:fdpzkz.qetg01.2wxsbn-qmf@smtp.gmail.com">
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<pre class="moz-quote-pre" wrap="">Are the risks and tradeoffs well enough understood (and visible enough
for troubleshooting) to recommend broader deployment?
I recently gave openwrt a try on some hardware that I ultimately
concluded was insufficient for the job. Fairly soon after changing out
my access point, I started getting complaints of Wi-Fi dropping in my
household, especially when someone was trying to videoconference. I
discovered that my AP was spontaneously rebooting, and the box was
getting hot.
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<pre class="moz-quote-pre" wrap="">
Most CPE devices these days rely on hardware accelerated packet forwarding to achieve their published specs. That's all about taking packets in one side and pushing them out the other as quickly as possible, with only minimal support from the CPU (likely, new connections get a NAT/firewall lookup, that's all). It has the advantages of speed and power efficiency, but unfortunately it is also incompatible with our debloating efforts. So debloated CPE will tend to run hotter and with lower peak throughput, which may be noticeable to cable and fibre users; VDSL (FTTC) users might have service of 80Mbps or less where this effect is less likely to matter.
It sounds like that AP had a very marginal thermal design which caused the hardware to overheat as soon as the CPU was under significant load, which it can easily be when a shaper and AQM are running on it at high throughput. The cure is to use better designed hardware, though you could also contemplate breaking the case open to cure the thermal problem directly. There are some known reliable models which could be collected into a list. As a rule of thumb, the ones based on ARM cores are likely to be designed with CPU performance more in mind than those with MIPS.
Cake has some features which can be used to support explicit classification and (de)prioritisation of traffic via firewall marking rules, either by rewriting the Diffserv field or by associating metadata with packets within the network stack (fwmark). This can be very useful for pushing Bittorrent or WinUpdate swarm traffic out of the way. But for most situations, the default flow-isolating behaviour already works pretty well, especially for ensuring that one computer's network load has only a bounded effect on any other. We can discuss that in more detail if that would be helpful.</pre>
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<p>I'm primarily thinking of <i>this week's</i> version of the home
router problem (;-)) <br>
</p>
<p>Because of the degree to which we're working from home and
videoconferencing, a lot of low-price, medium-performance devices
are suddenly too wimpy for their new role.</p>
<p>A (very!) draft version is up in Google docs, at
<a class="moz-txt-link-freetext" href="https://docs.google.com/document/d/1gWKp9HqTbuHLfgD59WU4KJ8Og3eHuBtIeC7BUK0Ju9w/edit?usp=sharing">https://docs.google.com/document/d/1gWKp9HqTbuHLfgD59WU4KJ8Og3eHuBtIeC7BUK0Ju9w/edit?usp=sharing</a></p>
<p>Using myself as the guinea-pig, running pfifo-fast was clearly
bad, fq_codel was better, and cake was good with a newish Fedora
and the stock Rogers router. It's been a while since I did rrul
tests, and in any case, I think that to convince readers we need a
very practical way of making it clear that they have a problem.
I'm thinking that making VOIP fail might do the trick (;-))</p>
<p>The hard part, IMHO, is constructing a test that immediately
communicates the idea that the reader has a problem, and that CAKE
addresses it. <br>
</p>
<p>Returning to the hardware question, <a class="moz-txt-link-freetext" href="https://evenroute.com/iqrv3">https://evenroute.com/iqrv3</a>
seems to be capable of handling up to ~300 Mbit/S connections, and
my ISP only delivers 170 (and advertises 150, which is mildly
surprising!)</p>
<p>I just ordered one, so I'll have a 'plug in" example, along with
reflashing my linksys for the umpty-thousandth time.<br>
</p>
<p>--dave<br>
</p>
<p>
<blockquote type="cite"> I suspect not enough people are aware of
the later efforts of the bufferbloat team, so I'm thinking of
one or two articles, starting with LWN and an audience of
aficionados.
<br>
<br>
The core community is aware of what we've done, but in my view
we haven't converted "grandma". Grandma, as well as a whole
bunch of ordinary engineers and partners of engineers, are
dependent on debloated performance because they're working at
home now, and competing with granddaughter playing video games
while they're trying to hold a video call.
<br>
<br>
Right now, my colleagues at work suffer from more than a second
of bloat-related lag. They therefore tend to speak over each
other on con-calls, apologize, start again and talk over each
other, again. After a little while, the picture becomes a
distinctly silly one: a bunch of grown adults putting their
hands up and waving, like little kids in school. No-one has
called out “me, me, teacher” yet, but I expect it any time.
<br>
<br>
I propose we show the results in terms that we can explain to
Grandma, specifically concentrating on functioning VOIP. I just
upgraded to Fedora 31, and the networking is absolutely stock,
so I make a perfect victim/guinea-pig (;-))
<br>
<br>
Who's interested?
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<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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