From: James Roberts <James.Roberts@inria.fr>
To: Dave Taht <dave.taht@gmail.com>
Cc: "aqm@ietf.org" <aqm@ietf.org>, bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] [aqm] TSO sizing fixes and the new paced "fq" scheduler in Linux 3.12
Date: Tue, 24 Sep 2013 14:25:49 +0200 [thread overview]
Message-ID: <2719938E-E24A-4A06-898F-CE90CBED005C@inria.fr> (raw)
In-Reply-To: <CAA93jw6JVMWqjwAU+uKWjjT4rW1jTZPBLF71PztVR-GEMvvrOw@mail.gmail.com>
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No one responded to Luca's Sept 1 comment (on the bloat list) that the new code seems to do tail drop rather than longest queue drop.
If this is so, bandwidth sharing will not be fair since FQ alone is not enough. This was shown in the previously cited Bell Labs paper : http://ect.bell-labs.com/who/stiliadi/papers/jsac99.pdf. The following table is copied from the paper.
These results are a kind of benchmark showing that fairness needs both FQ and LQD. The paper also shows that a more easily implemented, approximate LQD works OK and avoids the need to sort flow queues in size order.
Jim Roberts
They showed the
On 21 Sep 2013, at 01:18, Dave Taht wrote:
> The best writeup of Eric Dumazet's (and team's) latest assault on
> bloat was in lwn last month. The article just came out from behind the
> paywall for general reading and is here:
>
> http://lwn.net/Articles/564978/
>
> (I haven't fiddled with these new features because I'm in the final
> throes of getting a decent beta of cerowrt out on 3.10.12 with some
> annoy-the-nsa features in it. )
>
> The only benchmark I've seen on the new scheduler so far was:
>
> http://thread.gmane.org/gmane.linux.network/281023
>
> Anybody got relevant benchmarks?
>
> I am very happy to see the TSO/GSO sizing stuff as well. I hope that
> this will result in GSO doing sane things on 100Mbit and slower
> devices.
>
> --
> Dave Täht
> _______________________________________________
> aqm mailing list
> aqm@ietf.org
> https://www.ietf.org/mailman/listinfo/aqm
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next prev parent reply other threads:[~2013-09-24 12:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-20 23:18 [Bloat] " Dave Taht
2013-09-24 12:25 ` James Roberts [this message]
2013-09-25 15:15 ` [Bloat] [aqm] " Eric Dumazet
2013-09-25 15:38 ` Luca MUSCARIELLO
2013-09-25 16:58 ` Eric Dumazet
2013-09-29 5:49 ` Dave Taht
2013-09-29 8:02 ` Alex Elsayed
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