From: Dave Taht <dave.taht@gmail.com>
To: ecn-sane@lists.bufferbloat.net
Subject: [Ecn-sane] cwnd/2 - 1
Date: Fri, 7 Sep 2018 00:18:48 -0700 [thread overview]
Message-ID: <CAA93jw7-Oqs9p6MrLgk7Q0KcOVwM4EqrvFk_S7ox=gDOCt8eXQ@mail.gmail.com> (raw)
One of the things that went by in recent kernel changes was that
linux tcp at a cwnd 2 on a CE goes into quickack mode, so that we
get back one ack per packet (I think, from reading the commit) instead of
every other one.
halving cwnd and then taking off 1 more gives a response that drops the
mass closer along the lines of what a drop may do in response to loss
and re-ordering. A cwnd 1 in quickack mode would halve the number of
packets outstanding in my 100 flows test. I think.
another thing to note is that retransmits, are, by the standard, and
in linux, not protected by ECT, and when you get near to 100% mark
rate as i do in this artificial test, get dropped a lot.
--
Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619
next reply other threads:[~2018-09-07 7:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-07 7:18 Dave Taht [this message]
2018-09-10 11:26 ` Pete Heist
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