Cake - FQ_codel the next generation
 help / color / mirror / Atom feed
From: Dave Taht <dave.taht@gmail.com>
To: ecn-sane@lists.bufferbloat.net, Cake List <cake@lists.bufferbloat.net>
Subject: Re: [Cake] some 100 flow 100Mbit tests of cake, fq_codel, pie, with ecn on or off
Date: Fri, 21 Sep 2018 11:42:47 -0700	[thread overview]
Message-ID: <CAA93jw4rVBtwuyCyXOaMTsrJg-sOL4fybd5P1xhzLKoDpttp0w@mail.gmail.com> (raw)
In-Reply-To: <CAA93jw4UjJ1Fd8cuZJvaOp2FJFWG-qeo-rqKJgf0LaErLCxHSQ@mail.gmail.com>

On Fri, Sep 21, 2018 at 11:35 AM Dave Taht <dave.taht@gmail.com> wrote:
>
> As it happens, I'm primarily trying to get to the root causes of
> babeld going flaky on me, and my primary purpose was to test babeld
> 1.8.3 while under load, but I have a few observations in this dataset.
>
> It is WAY easier if you just download the tarball and use flent to
> look at the various graphs.
>
> so:
>
> wget http://flent-fremont.bufferbloat.net/~d/babel-ecn.tgz
>
> or browse: http://flent-fremont.bufferbloat.net/~d/babel-ecn/
>
> I started writing up things, with pictures, and so on, and that
> started to get long, and I want to finish blowing babel up (if I can)
> before I can safely deploy it so...
>
> The test was client <-> 100Mbit bottleneck <-> server
> with ecn on or off on cubic tcp.
>
> I ran most of them at a higher resolution (-s .02). See the included
> test script for more details. Running at this resolution required many
> minutes and 7GB's of memory to post-process the files.
>
> I need to go fix tc-iterate so I can get queue depths again. I'd also
> like to add irtt support to tcp_nup - I'm A) mostly interested in
> making babel fail, and B) tcp flows
>
> I did collect a ton of interesting statistics on the tcp flows. The
> tcp rtt CDFs, in particular.
>
> The files with no qdisc mentioned are cake.
>
> 0) I did the fq_codel_fast tests using memlimit 4M (the openwrt
> default, so far as I know(?)
>
> 1) At this workload, pie's ecn support gets disabled almost completely
> - the drop probability cracks 10% and it drops away... something like
> 370 packets marked vs 49000 dropped.
>
> * You can see cake doing quite well vis a vis fq_codel, but you can
> also see that the RTT is inflated in either case with ecn on vs off.
>
> * You can see the effects of hash collisions on codel - one test had a
> major hash collision on the measurement flow.
>
> * Probably the most interesting result (and one reason why I started
> fiddling with the bulk dropper code in the first place)
>
> was cake vs fq_codel_fast, attached.

To clarify, the ruler flat line is cake.

The other line is fq_codel and it's collisions.

> But: DO suck down these files and peruse for yourself.
>
> --
>
> Dave Täht
> CTO, TekLibre, LLC
> http://www.teklibre.com



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

      reply	other threads:[~2018-09-21 18:43 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-21 18:35 Dave Taht
2018-09-21 18:42 ` Dave Taht [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://lists.bufferbloat.net/postorius/lists/cake.lists.bufferbloat.net/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAA93jw4rVBtwuyCyXOaMTsrJg-sOL4fybd5P1xhzLKoDpttp0w@mail.gmail.com \
    --to=dave.taht@gmail.com \
    --cc=cake@lists.bufferbloat.net \
    --cc=ecn-sane@lists.bufferbloat.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox