From: Pete Heist <pete@heistp.net>
To: Jonathan Morton <chromatix99@gmail.com>
Cc: Dave Taht <dave.taht@gmail.com>, bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] debloats/day metric?
Date: Mon, 27 Aug 2018 11:32:46 +0200 [thread overview]
Message-ID: <DDF55483-A834-4719-A764-188E09A3A32D@heistp.net> (raw)
In-Reply-To: <0C7983D3-4452-4DEF-87A6-2200A106FAB9@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1497 bytes --]
> On Aug 27, 2018, at 10:02 AM, Jonathan Morton <chromatix99@gmail.com> wrote:
>
>> On 27 Aug, 2018, at 10:44 am, Pete Heist <pete@heistp.net> wrote:
>>
>> …request pairs, one given strict priority at the bottleneck and one best effort, then measure the difference between the two (for both RTT and OWD).
>>
>> Assuming this yields useful data…
>
> For the overwhelming majority of bloated bottlenecks, it will not - because they have zero concept of "strict priority".
To clarify, I control the bottleneck link and would give that priority with tc for a chosen dscp marking, then use that marking in one of the two requests in the pair. That would be required to make this measurement. I realize there are other areas in the stack though where I can’t give priority that may sufficiently pollute the results.
But, as a rough illustration, attached are two flent rrul_be runs with and without cake on my home connection (p2p WiFi with an airOS device). In the plot without cake, it’s pretty clear that ICMP is being prioritized, as its RTT stays relatively stable under load, while UDP RTT increases. (I believe this prioritization happens when airMAX is enabled in airOS, because when it’s disabled, ICMP and UDP RTTs under load are almost identical.)
Presumably, the difference between the two RTTs would approximate bloat. Or if not, why not? And presumably, I could create a similar effect by giving priority to one of two requests in a pair...
Pete
[-- Attachment #2.1: Type: text/html, Size: 2584 bytes --]
[-- Attachment #2.2: flent-london-nocake.jpg --]
[-- Type: image/jpeg, Size: 121243 bytes --]
[-- Attachment #2.3: flent-london-cake.jpg --]
[-- Type: image/jpeg, Size: 140300 bytes --]
prev parent reply other threads:[~2018-08-27 9:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-25 16:57 Dave Taht
2018-08-27 7:44 ` Pete Heist
2018-08-27 8:02 ` Jonathan Morton
2018-08-27 9:32 ` Pete Heist [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/bloat.lists.bufferbloat.net/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=DDF55483-A834-4719-A764-188E09A3A32D@heistp.net \
--to=pete@heistp.net \
--cc=bloat@lists.bufferbloat.net \
--cc=chromatix99@gmail.com \
--cc=dave.taht@gmail.com \
/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