From: Dave Taht <dave@taht.net>
To: Luca Muscariello <luca.muscariello@gmail.com>
Cc: Sebastian Moeller <moeller0@gmx.de>,
bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] benefits of ack filtering
Date: Fri, 01 Dec 2017 10:43:22 -0800 [thread overview]
Message-ID: <874lpagugl.fsf@nemesis.taht.net> (raw)
In-Reply-To: <CAHx=1M5GG7BErHvG3ntvyUKv02CMMj8M=XftqzGM_+7JDxHPqQ@mail.gmail.com> (Luca Muscariello's message of "Fri, 1 Dec 2017 11:45:19 +0100")
Luca Muscariello <luca.muscariello@gmail.com> writes:
> For highly asymmetric links, but also shared media like wifi, QUIC might be a
> better playground for optimisations.
> Not pervasive as TCP though and maybe off topic in this thread.
I happen to really like QUIC, but a netperf-style tool did not exist for
it when I last looked, last year.
Also getting to emulating DASH traffic is on my list.
>
> If the downlink is what one want to optimise, using FEC in the downstream, in
> conjunction with flow control could be very effective.
> No need to send ACK frequently and having something like FQ_codel in the
> downstream would avoid fairness problems that might
> happen though. I don't know if FEC is still in QUIC and used.
>
> BTW, for wifi, the ACK stream can be compressed in aggregate of frames and sent
> in bursts. This is similar to DOCSIS upstream.
> I wonder if this is a phenomenon that is visible in recent WiFi or just
> negligible.
My guess is meraki deployed something and I think they are in in the top
5 in the enterprise market.
I see ubnt added airtime fairness (of some sort), recently.
>
> On Fri, Dec 1, 2017 at 9:45 AM, Sebastian Moeller <moeller0@gmx.de> wrote:
>
> Hi All,
>
> you do realize that the worst case is going to stay at 35KPPS? If we assume
> simply that the 100Mbps download rate is not created by a single flow but by
> many flows (say 70K flows) the discussed ACK frequency reduction schemes
> will not work that well. So ACK thinning is a nice optimization, but will
> not help the fact that some ISPs/link technologies simply are asymmetric and
> the user will suffer under some traffic conditions. Now the 70K flow example
> is too extreme, but the fact is at hight flow number with sparse flows (so
> fewer ACKs per flow in the queue and fewer ACKs per flow reaching the end
> NIC in a GRO-collection interval (I naively assume there is a somewhat fixed
> but small interval in which packets of the same flow are collected for GRO))
> there will be problems. (Again, I am all for allowing the end user to
> configure ACK filtering thinning, but I would rather see ISPs sell less
> imbalanced links ;) )
>
> Best Regards
> Sebastian
>
>
>
> > On Dec 1, 2017, at 01:28, David Lang <david@lang.hm> wrote:
> >
> > 35K PPS of acks is insane, one ack every ms is FAR more than enough to do
> 'fast recovery', and outside the datacenter, one ack per 10ms is probably
> more than enough.
> >
> > Assuming something that's not too assymetric, thinning out the acks may
> not make any difference in the transfer rate of a single data flow in one
> direction, but if you step back and realize that there may be a need to
> transfer data in the other direction, things change here.
> >
> > If you have a fully symmetrical link, and are maxing it out in both
> direction, going from 35K PPs of aks competing with data packets and gonig
> down to 1k PPS or 100 PPS (or 10 PPS) would result in a noticable
> improvement in the flow that the acks are competing against.
> >
> > Stop thinking in terms of single-flow benchmarks and near idle 'upstream'
> paths.
> >
> > David Lang
> > _______________________________________________
> > Bloat mailing list
> > Bloat@lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/bloat
>
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat
>
>
>
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat
next prev parent reply other threads:[~2017-12-01 18:43 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-28 21:48 Dave Taht
2017-11-29 6:09 ` Mikael Abrahamsson
2017-11-29 9:34 ` Sebastian Moeller
2017-11-29 12:49 ` Mikael Abrahamsson
2017-11-29 13:13 ` Luca Muscariello
2017-11-29 14:31 ` Mikael Abrahamsson
2017-11-29 14:36 ` Jonathan Morton
2017-11-29 15:24 ` Andrés Arcia-Moret
2017-11-29 15:53 ` Luca Muscariello
[not found] ` <CAJq5cE3qsmy8EFYZmQsLL_frm8Tty9Gkm92MQPZ649+kpM1oMw@mail.gmail.com>
2017-11-29 16:13 ` Jonathan Morton
2017-11-30 7:03 ` Michael Welzl
2017-11-30 7:24 ` Dave Taht
2017-11-30 7:45 ` Dave Taht
2017-11-30 7:48 ` Jonathan Morton
2017-11-30 8:00 ` Luca Muscariello
2017-11-30 10:24 ` Eric Dumazet
2017-11-30 13:04 ` Mikael Abrahamsson
2017-11-30 15:51 ` Eric Dumazet
2017-12-01 0:28 ` David Lang
2017-12-01 7:09 ` Jan Ceuleers
2017-12-01 12:53 ` Toke Høiland-Jørgensen
2017-12-01 13:13 ` [Bloat] [Make-wifi-fast] " Кирилл Луконин
2017-12-01 13:22 ` Luca Muscariello
2017-12-11 17:42 ` Simon Barber
2017-12-01 13:17 ` [Bloat] " Luca Muscariello
2017-12-01 13:40 ` Toke Høiland-Jørgensen
2017-12-01 17:42 ` Dave Taht
2017-12-01 20:39 ` Juliusz Chroboczek
2017-12-03 5:20 ` [Bloat] [Make-wifi-fast] " Bob McMahon
2017-12-03 10:35 ` Juliusz Chroboczek
2017-12-03 11:40 ` Jan Ceuleers
2017-12-03 13:57 ` Juliusz Chroboczek
2017-12-03 14:07 ` Mikael Abrahamsson
2017-12-03 19:53 ` Juliusz Chroboczek
2017-12-03 14:09 ` Ryan Mounce
2017-12-03 19:54 ` Juliusz Chroboczek
2017-12-03 20:14 ` Sebastian Moeller
2017-12-03 22:27 ` Dave Taht
2017-12-03 15:25 ` Robert Bradley
2017-12-04 3:44 ` Dave Taht
2017-12-04 14:38 ` David Collier-Brown
2017-12-04 15:44 ` Juliusz Chroboczek
2017-12-04 17:17 ` David Collier-Brown
2017-12-03 19:04 ` Bob McMahon
2017-12-01 21:17 ` Bob McMahon
2017-12-01 8:45 ` [Bloat] " Sebastian Moeller
2017-12-01 10:45 ` Luca Muscariello
2017-12-01 18:43 ` Dave Taht [this message]
2017-12-01 18:57 ` Luca Muscariello
2017-12-01 19:36 ` Dave Taht
2017-11-30 14:51 ` Neal Cardwell
2017-11-30 15:55 ` Eric Dumazet
2017-11-30 15:57 ` Neal Cardwell
2017-11-29 16:50 ` Sebastian Moeller
2017-12-12 19:27 ` Benjamin Cronce
2017-12-12 20:04 ` Dave Taht
2017-12-12 21:03 ` David Lang
2017-12-12 21:29 ` Jonathan Morton
2017-12-12 22:03 ` Jonathan Morton
2017-12-12 22:21 ` David Lang
[not found] ` <CAJq5cE3nfSQP0GCLjp=X0T-iHHgAs=YUCcr34e3ARgkrGZe-wg@mail.gmail.com>
2017-12-12 22:41 ` Jonathan Morton
2017-12-13 9:46 ` Mikael Abrahamsson
2017-12-13 10:03 ` Jonathan Morton
2017-12-13 12:11 ` Sebastian Moeller
2017-12-13 12:18 ` Jonathan Morton
2017-12-13 12:36 ` Sebastian Moeller
2017-12-13 12:39 ` Luca Muscariello
2017-11-29 18:21 ` Juliusz Chroboczek
2017-11-29 18:41 ` Dave Taht
2017-11-29 23:29 ` Steinar H. Gunderson
2017-11-29 23:59 ` Stephen Hemminger
2017-11-30 0:21 ` Eric Dumazet
2017-12-11 20:15 ` Benjamin Cronce
2017-11-29 18:28 ` Juliusz Chroboczek
2017-11-29 18:48 ` Dave Taht
2017-12-11 18:30 ` Jonathan Morton
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=874lpagugl.fsf@nemesis.taht.net \
--to=dave@taht.net \
--cc=bloat@lists.bufferbloat.net \
--cc=luca.muscariello@gmail.com \
--cc=moeller0@gmx.de \
/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