From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-x230.google.com (mail-io0-x230.google.com [IPv6:2607:f8b0:4001:c06::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id E32143BA8E for ; Wed, 18 Apr 2018 14:06:45 -0400 (EDT) Received: by mail-io0-x230.google.com with SMTP id y128-v6so3507116iod.4 for ; Wed, 18 Apr 2018 11:06:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=OBuzvIWIN9Es4cE3uNH4u8uuuAfqPI+WtAR86Q8vs7I=; b=uAQ2ev6AlUhkA/FYPdDf+OVwWzZARGQGp3/PXoVWhIiWQ8icdZ5eNoeEVgtv9H//hP 5cpZ7r3dClJcn2ZIVEI1FUT0gWUqui3hOQDRuWAp+GkuMtz8uL/YqRy9hRwe86jIwo2G qhmvRxduZW0dYo2PH7sQSYA+UuO3sla+HFEe4R9DVKrcxpE7BrfbCzCeAMyDO5lfab6s tuT6MNVYZ4G4MqM0NZBDRcFJid6+Luz40/SNPivXkjO1O2wYi0hsWDOas/U46FRPcqLC NlGWNYeXWFVV8CwLXyMf/SIwguGyRru0PCrTPkAwqb5eEvnjWCd3yhKTA6ULqIa1+HBp OTgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=OBuzvIWIN9Es4cE3uNH4u8uuuAfqPI+WtAR86Q8vs7I=; b=l0qsWLnmG4qojlLqVquxbOITCmVCyloJRJrKzNlVKyAI2gJZHpDk8DSnFg2wXvFC0B aMLmrP2nbU5iQrp/GeQpaXABBI4WrbuaPJCfsd7Hj+HqbauBBu9oAmENmdVl2+Sv1LbK cRT9li23JD7pWIpeSv6jLCRXjSxAH9x4oz/oxA8hZG7kC2chtyzAqFR1/QT2NX1soND1 AX8WGnTJGxiqnANVKYPb2vRJTxQp2AHcT7brY1wQpdjSY8Zck8KJ772RbeJCAit5NzO+ jmNjV3RVZcwv8pcUxkb8AqWxtfrINwRiItB4SmIu/5BkHdbSPYg4dZFK+Zzgz/cFVFCa YpZA== X-Gm-Message-State: ALQs6tBz32wr1Oe1WQZgykjjAFDiA0IGdvCpXr6lfLUV/mIGlFIlEqJZ T5WFmnL9+I2/KguMYfiLEC4g3mJXJEROhGkrLts= X-Google-Smtp-Source: AB8JxZouQFiAZ2KQ/h3c4oE7OQze/QUhv/FauiSboqClDvX0aTxSlBD5CuaJ0saqPiMRPh8YdONtR/DIK9lJlsChQGo= X-Received: by 2002:a6b:520b:: with SMTP id g11-v6mr165149iob.31.1524074805245; Wed, 18 Apr 2018 11:06:45 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:6c85:0:0:0:0:0 with HTTP; Wed, 18 Apr 2018 11:06:44 -0700 (PDT) In-Reply-To: References: <87vacq419h.fsf@toke.dk> <874lk9533l.fsf@toke.dk> <87604o3get.fsf@toke.dk> <578552B2-5127-451A-AFE8-93AE9BB07368@gmail.com> <87r2nc1taq.fsf@toke.dk> <0BB8B1FD-6A00-49D6-806E-794BD53A449F@gmx.de> <3457DD8E-0292-4802-BD1E-B37771DCADA2@gmail.com> <87fu3s1om2.fsf@toke.dk> <5BD20E12-2408-4393-8560-3FDA52D86DB3@gmail.com> From: =?UTF-8?Q?Jonas_M=C3=A5rtensson?= Date: Wed, 18 Apr 2018 20:06:44 +0200 Message-ID: To: Dave Taht Cc: Jonathan Morton , Cake List Content-Type: multipart/alternative; boundary="00000000000060bcb6056a235123" Subject: Re: [Cake] A few puzzling Cake results X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Apr 2018 18:06:46 -0000 --00000000000060bcb6056a235123 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Dave, in the thread referenced earlier that led to this change you said: "The loss of throughput here compared to non-ingress mode is a blocker for mainlining and for that matter, wedging this into lede." I'm curious, what would the latency be in Toke's experiment with non-ingress mode and with the 4 MTU change reverted? The same as for fq_codel? On Wed, Apr 18, 2018 at 7:02 PM, Dave Taht wrote: > Jonathan: > > I think you are wrong. What we care about is keeping packets in flight > across the network, with a queue length as close to 1 packet as > possible. > > If it breaks ingress mode so be it. > > > On Wed, Apr 18, 2018 at 9:54 AM, Jonathan Morton > wrote: > >> On 18 Apr, 2018, at 7:11 pm, Toke H=C3=B8iland-J=C3=B8rgensen > wrote: > >> > >> What you're saying here is that you basically don't believe there are > >> any applications where a bulk TCP flow would also want low queueing > >> latency? :) > > > > I'm saying that there's a tradeoff between intra-flow induced latency > and packet loss, and I've chosen 4 MTUs as the operating point. > > > > Bear in mind that with high packet loss, the retransmissions take an > extra RTT to complete in any case, and there's a higher probability of > incurring an RTO which will *really* hurt your intra-flow latency. > > > > This equation is modified with ECN because a high signalling rate > doesn't result in packet loss or retransmissions, but I'm not presently > making any decisions based on ECN support, except the obvious one of > whether to mark or drop. > > > > - Jonathan Morton > > > > _______________________________________________ > > Cake mailing list > > Cake@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/cake > > > > -- > > Dave T=C3=A4ht > CEO, TekLibre, LLC > http://www.teklibre.com > Tel: 1-669-226-2619 > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake > --00000000000060bcb6056a235123 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Dave, in the thread referenced earlier that led to this ch= ange you said:

"The loss of throughput here compare= d to non-ingress mode is a blocker for mainlining and for that matter, wedg= ing this into lede."

I'm curious, what wo= uld the latency be in Toke's experiment with non-ingress mode and with = the 4 MTU change reverted? The same as for fq_codel?


On Wed, Apr 1= 8, 2018 at 7:02 PM, Dave Taht <dave.taht@gmail.com> wrote:=
Jonathan:

I think you are wrong. What we care about is keeping packets in flight
across the network, with a queue length as close to 1 packet as
possible.

If it breaks ingress mode so be it.


On Wed, Apr 18, 2018 at 9:54 AM, Jonathan Morton <chromatix99@gmail.com> wrote:
>> On 18 Apr, 2018, at 7:11 pm, Toke H=C3=B8iland-J=C3=B8rgensen <= toke@toke.dk> wrote:
>>
>> What you're saying here is that you basically don't believ= e there are
>> any applications where a bulk TCP flow would also want low queuein= g
>> latency? :)
>
> I'm saying that there's a tradeoff between intra-flow induced = latency and packet loss, and I've chosen 4 MTUs as the operating point.=
>
> Bear in mind that with high packet loss, the retransmissions take an e= xtra RTT to complete in any case, and there's a higher probability of i= ncurring an RTO which will *really* hurt your intra-flow latency.
>
> This equation is modified with ECN because a high signalling rate does= n't result in packet loss or retransmissions, but I'm not presently= making any decisions based on ECN support, except the obvious one of wheth= er to mark or drop.
>
>=C2=A0 - Jonathan Morton
>
> _______________________________________________
> Cake mailing list
> Cake@lists.bufferbloat.n= et
> https://lists.bufferbloat.net/listinfo/cake=



--

Dave T=C3=A4ht
CEO, TekLibre, LLC
ht= tp://www.teklibre.com
Tel: 1-669-226-2619
____________________________= ___________________
Cake mailing list
Cake@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cake

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