From nobody Wed Oct 26 12:59:32 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 4My8625q4Bz4g3V7 for ; Wed, 26 Oct 2022 12:59:38 +0000 (UTC) (envelope-from thj@freebsd.org) Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com [66.111.4.27]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4My8614xFFz45wb; Wed, 26 Oct 2022 12:59:37 +0000 (UTC) (envelope-from thj@freebsd.org) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 2EE115C00F3; Wed, 26 Oct 2022 08:59:37 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Wed, 26 Oct 2022 08:59:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:in-reply-to:message-id :mime-version:references:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm3; t=1666789177; x=1666875577; bh=3KdK13NmYKmsZ5KX6CaIy/zwd7/g oH7mJVdtUBMYyMc=; b=fRc4FMqbU6bw4upwnBNb/E2wG20mRfcoHKrVu1522SY4 u1pjtMrxuiGSL1jsTYlcEpU6eBXqcWP6gGTrazItLD3san+gpbFb/jdH4kG60UTz X3lR4/SzCF6D6rTSfyT2BimnyxvZM82tXWg3XH1ax3U5/nqFCbrYg0Eli94rZnlO URlZW8I0tm572vqEQ3pejHXZe8u3BKH309vC76TWqE39zWkZaFNRwAF/qS7GaGxv TEt/p9fxC/crujQF/w5tNyG4xGBS4N0WITjCshRqgnHbtF+gptVB1lUwd7jMo7Zf q9e4bGL8z3L1Yg4X75dMB2EleslycAgfBgbbkX82Cg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvgedrtddvgdehkecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvvefukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpefvohhmucfl ohhnvghsuceothhhjhesfhhrvggvsghsugdrohhrgheqnecuggftrfgrthhtvghrnhepje elfeduiedvveffveeukeekffffveeiudejkeeuleeihfeludeuieeuvefhfeejnecuffho mhgrihhnpeifihhlvgihrdgtohhmnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrg hmpehmrghilhhfrhhomhepthhhjhesfhhrvggvsghsugdrohhrgh X-ME-Proxy: Feedback-ID: ib75146ab:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 26 Oct 2022 08:59:35 -0400 (EDT) Date: Wed, 26 Oct 2022 13:59:32 +0100 From: Tom Jones To: tuexen@freebsd.org Cc: Hans Petter Selasky , Zhenlei Huang , freebsd-net@freebsd.org Subject: Re: Too aggressive TCP ACKs 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> 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 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E92E238-798B-4293-B0D2-81E3FCB92E34@freebsd.org> X-Rspamd-Queue-Id: 4My8614xFFz45wb X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=messagingengine.com header.s=fm3 header.b=fRc4FMqb; dmarc=none; spf=softfail (mx1.freebsd.org: 66.111.4.27 is neither permitted nor denied by domain of thj@freebsd.org) smtp.mailfrom=thj@freebsd.org X-Spamd-Result: default: False [-2.40 / 15.00]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; DWL_DNSWL_LOW(-1.00)[messagingengine.com:dkim]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-0.997]; MID_RHS_NOT_FQDN(0.50)[]; R_DKIM_ALLOW(-0.20)[messagingengine.com:s=fm3]; MIME_GOOD(-0.10)[text/plain]; RCVD_IN_DNSWL_LOW(-0.10)[66.111.4.27:from]; MIME_TRACE(0.00)[0:+]; DMARC_NA(0.00)[freebsd.org]; TAGGED_RCPT(0.00)[]; R_SPF_SOFTFAIL(0.00)[~all:c]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_SOME(0.00)[]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org]; RCVD_COUNT_THREE(0.00)[4]; RCPT_COUNT_THREE(0.00)[4]; FROM_HAS_DN(0.00)[]; ASN(0.00)[asn:19151, ipnet:66.111.4.0/24, country:US]; RCVD_TLS_LAST(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; ARC_NA(0.00)[]; FREEMAIL_CC(0.00)[selasky.org,gmail.com,freebsd.org]; DKIM_TRACE(0.00)[messagingengine.com:+]; FREEFALL_USER(0.00)[thj]; RCVD_VIA_SMTP_AUTH(0.00)[] X-ThisMailContainsUnwantedMimeParts: N On Wed, Oct 26, 2022 at 02:55:21PM +0200, tuexen@freebsd.org wrote: > > On 26. Oct 2022, at 10:57, Tom Jones wrote: > > > > On Sat, Oct 22, 2022 at 12:14:25PM +0200, Hans Petter Selasky wrote: > >> Hi, > >> > >> Some thoughts about this topic. > >> > >> Delaying ACKs means loss of performance when using Gigabit TCP > >> connections in data centers. There it is important to ACK the data as > >> quick as possible, to avoid running out of TCP window space. Thinking > >> about TCP connections at 30 GBit/s and above! > >> > >> I think the implementation should be exactly like it is. > >> > >> There is a software LRO in FreeBSD to coalesce the ACKs before they hit > >> the network stack, so there are no real problems there. > >> > > > > Changing the ACK ratio seems to be okay in most cases, a paper I wrote > > about this was published this week: > > > > https://onlinelibrary.wiley.com/doi/10.1002/sat.1466 > > > > It focuses on QUIC, but congestion control dynamics don't change with > > the protocol. You should be able to read there, but if not I'm happy to > > send anyone a pdf. > Is QUIC using an L=2 for ABC? I think that is the rfc recommendation, actual deployed reality is more scattershot. - Tom