From: Jonathan Morton <chromatix99@gmail.com>
To: Dave Taht <dave.taht@gmail.com>
Cc: ECN-Sane <ecn-sane@lists.bufferbloat.net>
Subject: Re: [Ecn-sane] rfc3168 sec 6.1.2
Date: Thu, 29 Aug 2019 11:02:41 +0300 [thread overview]
Message-ID: <F0DF005B-21F2-4B91-B9A2-855CFE60B1DC@gmail.com> (raw)
In-Reply-To: <CAA93jw7tkKEQF_BiGOrnE2j79-7m3wNOOrMSmGRg613DMvdg1w@mail.gmail.com>
> On 29 Aug, 2019, at 5:08 am, Dave Taht <dave.taht@gmail.com> wrote:
>
> It would explain a lot if this was not actually implemented in Linux.
> I'm afraid to look. cwnd reduction is capped to 2. 1 should put you
> in quickack mode AND to go lower seemingly it's supposed to
> then rely on the retransmit timer.
Nowadays the same effect can be obtained from the pacing timer. Just set the CA scale factor to 50% to get an effective minimum cwnd of 1, or lower still if needed.
In most of our SCE testing, we're now setting the SS scale factor to 100% (the default is 200%, which means the cwnd is sent over half an RTT and the other half is idle) and the CA scale factor to 40% (default is 120%, so the effective minimum cwnd is actually 2.4 from a packet-pair standpoint). See the last substantive slide in the IETF-105 SCE deck.
- Jonathan Morton
next prev parent reply other threads:[~2019-08-29 8:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 2:08 Dave Taht
2019-08-29 8:02 ` Jonathan Morton [this message]
2019-08-29 13:51 ` Dave Taht
2019-08-29 14:35 ` Jeremy Harris
2019-08-29 14:42 ` Jonathan Morton
2019-08-29 19:10 ` Dave Taht
2019-08-29 19:45 ` Dave Taht
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