Cake - FQ_codel the next generation
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From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Dave Taht <dave.taht@gmail.com>, Cake List <cake@lists.bufferbloat.net>
Subject: Re: [Cake] a bunch of sch_cake vs everything tests at 100mbit on net-next
Date: Wed, 01 Aug 2018 11:52:12 +0200	[thread overview]
Message-ID: <87zhy6xvlf.fsf@toke.dk> (raw)
In-Reply-To: <CAA93jw5mEWTYzwmOmTPBwds7cKUt+Dm4oh3sbBXgu7EvoGc-YA@mail.gmail.com>

Dave Taht <dave.taht@gmail.com> writes:

> I wanted to look at a few things - cpu usage, 4 different tcps,
> different server schedulers, ecn vs non-ecn, sqm fq_codel simplest.qos
> vs cake, etc, etc. I just did tcp_ndown tests of 128 flows to see what
> happened for starters. I also tried to capture tcp_cwnd, etc, stats,
> but that seems not to be plotting in flent....
>
> My first objective, of course, was to make sure upstream cake didn't
> crash. It didn't. No real surprises, cake ecn causes some more
> collateral inter-packet latency damage, cake (aside from general cpu
> over-usage) is a mild win across the board... including, surprisingly,
> tail drop queue depth. (see below)
>
> metric ton of flent files: http://www.taht.net/~d/cake_128flows.tgz
> (script therein)
> topology: server -> apu2 -> switch -> client (no switch between the
> apu2 and server)
>
> A couple notes:
>
> 1) ecn_vs_bbr_ineffective.png:
>
> vs bbr in ecn mode, (thus rendering codel or cake ineffective and
> reverting to tail drop) "sqm simplest.qos" at this speed (100mbit)
> uses a too large packet limit vs what cake uses. I will argue in favor
> of using the new "memlimit" parameter to fq_codel in the sqm scripts
> to better limit the buffer size.

Openwrt carries a patch to default the memlimit to 4 MB rather than 32...

-Toke

      reply	other threads:[~2018-08-01  9:52 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-31 21:12 Dave Taht
2018-08-01  9:52 ` Toke Høiland-Jørgensen [this message]

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