<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252">
</head>
<body>
<br>
A tangent for anyone who is running a FreeBSD-based gateway, there's
also an fq_pie in dummynet (<a class="moz-txt-link-freetext" href="https://reviews.freebsd.org/rS300779">https://reviews.freebsd.org/rS300779</a>). I
haven't played with it for a long time, but still curious if
anyone's experimented with that combination. (Particularly if the
on-the-wire behavior differs from that of linux fq-pie.)<br>
<br>
cheers,<br>
gja<br>
<br>
<div class="moz-cite-prefix">On 2020-07-16 10:37, Jonathan Morton
wrote:<br>
</div>
<blockquote type="cite" cite="mid:156954CF-BCBC-4B0C-9C42-A2A6F2450185@gmail.com">
> On 16 Jul, 2020, at 12:58 am, Michael Yartys via Bloat
<a class="moz-txt-link-rfc2396E" href="mailto:bloat@lists.bufferbloat.net"><bloat@lists.bufferbloat.net></a> wrote:<br>
> <br>
> Are there any major differences between fq_codel and fq_pie
in terms of their performance?<br>
<br>
I think some tests were run some time ago which showed
significantly better behaviour by fq_codel than fq_pie. In
particular, the latter used only a single AQM instead of an
independent one for each flow. I'm not sure whether it's been
changed since then.<br>
<br>
The only advantage I can see for PIE over Codel is, possibly, a
reduction of system load for use of the AQM. But fq_codel is
already pretty efficient so that would be an edge case.<br>
<br>
In any case, it is already possible to chose any qdisc you like
(with default parameters) as the default qdisc. I'm really not
sure what the fuss is about.<br>
<br>
> And how does the improved fq_codel called cobalt, which is
used in cake, stack up?<br>
<br>
COBALT has some modifications to basic Codel which, I think, could
profitably be backported into fq_codel. It also has a particular
extra mode, based on BLUE, for dealing with unresponsive traffic
(that continued to build queue even after lots of ECN signalling
and/or Cdel-scheduled packet drops). It is the latter which
inspired the name.<br>
<br>
For the other major functional component of fq_codel, Cake also
has a set-associative hash function for allocating flows into
queues, which substantially reduces the probability of hash
collisions in most cases.<br>
<br>
- Jonathan Morton<br>
_______________________________________________<br>
Bloat mailing list<br>
<a class="moz-txt-link-abbreviated" href="mailto:Bloat@lists.bufferbloat.net">Bloat@lists.bufferbloat.net</a><br>
<a href="https://lists.bufferbloat.net/listinfo/bloat" moz-do-not-send="true">https://lists.bufferbloat.net/listinfo/bloat</a><br>
</blockquote>
<br>
</body>
</html>