From nobody Thu Oct 27 19:33:02 2022 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4Mywnb6LlVz4ft1N for ; Thu, 27 Oct 2022 19:33:07 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from drew.franken.de (mail-n.franken.de [193.175.24.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.franken.de", Issuer "Sectigo RSA Domain Validation Secure Server CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4MywnZ62CVz3FSP; Thu, 27 Oct 2022 19:33:06 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from smtpclient.apple (unknown [IPv6:2a02:8109:1140:c3d:d560:2a3a:db1f:1d6f]) (Authenticated sender: macmic) by drew.franken.de (Postfix) with ESMTPSA id 0D2A680593412; Thu, 27 Oct 2022 21:33:03 +0200 (CEST) Content-Type: text/plain; charset=us-ascii List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.200.110.1.12\)) Subject: Re: Too aggressive TCP ACKs From: tuexen@freebsd.org In-Reply-To: Date: Thu, 27 Oct 2022 21:33:02 +0200 Cc: Tom Jones , Hans Petter Selasky , Zhenlei Huang , "freebsd-net@freebsd.org" Content-Transfer-Encoding: quoted-printable Message-Id: References: <75D35F36-7759-4168-ADBA-C2414F5B53BC@gmail.com> <712641B3-5196-40CC-9B64-04637F16F649@lurchi.franken.de> <62A0DD30-B3ED-48BE-9C01-146487599092@gmail.com> <0FED34A9-D093-442A-83B7-08C06D11F8B5@lurchi.franken.de> <330A9146-F7CC-4CAB-9003-2F90B872AC3E@gmail.com> <1ed66217-5463-fd4d-7e7a-58d9981bc44c@selasky.org> <4E92E238-798B-4293-B0D2-81E3FCB92E34@freebsd.org> <701FC3D6-7AFE-46F6-977D-75CAD34646D4@freebsd.org> To: "Scheffenegger, Richard" X-Mailer: Apple Mail (2.3731.200.110.1.12) X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=disabled version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mail-n.franken.de X-Rspamd-Queue-Id: 4MywnZ62CVz3FSP X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=softfail (mx1.freebsd.org: 193.175.24.27 is neither permitted nor denied by domain of tuexen@freebsd.org) smtp.mailfrom=tuexen@freebsd.org X-Spamd-Result: default: False [-1.19 / 15.00]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.99)[-0.993]; MV_CASE(0.50)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_IN_DNSWL_LOW(-0.10)[193.175.24.27:from]; TAGGED_RCPT(0.00)[]; DMARC_NA(0.00)[freebsd.org]; TO_DN_EQ_ADDR_SOME(0.00)[]; FROM_NO_DN(0.00)[]; RCVD_TLS_ALL(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; FREEMAIL_CC(0.00)[freebsd.org,selasky.org,gmail.com]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org]; FREEFALL_USER(0.00)[tuexen]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; R_SPF_SOFTFAIL(0.00)[~all:c]; TO_DN_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCPT_COUNT_FIVE(0.00)[5]; R_DKIM_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; ASN(0.00)[asn:680, ipnet:193.174.0.0/15, country:DE]; RCVD_COUNT_TWO(0.00)[2] X-ThisMailContainsUnwantedMimeParts: N > On 27. Oct 2022, at 10:08, Scheffenegger, Richard = wrote: >=20 >>>>> It focuses on QUIC, but congestion control dynamics don't change=20= >>>>> with the protocol. You should be able to read there, but if not = I'm=20 >>>>> happy to send anyone a pdf. >>>> Is QUIC using an L=3D2 for ABC? >>>=20 >>> I think that is the rfc recommendation, actual deployed reality is=20= >>> more scattershot. >> Wouldn't that be relevant? If you get an ack for, let's say 8 = packets, you would only increment (in slow start) the cwnd by 2 packets, = not 8? >>=20 >> Best regards >> Michael >=20 > Isn't that the optimization in Linux with QuickAck during the periods, = where the data receiver assumes, that the sender is still in SlowStart - = and acking every packet? Sure. But that is not specified... I just wanted to point out that = simply "Changing the ACK ratio seems to be okay in most cases" might be more = complex than the sentence reads... Best regards Michael >=20 > Richard >=20