From owner-svn-src-all@freebsd.org Fri Jan 5 13:49:32 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8112CEAA54F; Fri, 5 Jan 2018 13:49:32 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from hz.grosbein.net (hz.grosbein.net [78.47.246.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hz.grosbein.net", Issuer "hz.grosbein.net" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 2380369C0C; Fri, 5 Jan 2018 13:49:31 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from eg.sd.rdtc.ru (root@eg.sd.rdtc.ru [62.231.161.221] (may be forged)) by hz.grosbein.net (8.15.2/8.15.2) with ESMTPS id w05DnIZc038388 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 5 Jan 2018 14:49:19 +0100 (CET) (envelope-from eugen@grosbein.net) X-Envelope-From: eugen@grosbein.net X-Envelope-To: steven@multiplay.co.uk Received: from [10.58.0.4] ([10.58.0.4]) by eg.sd.rdtc.ru (8.15.2/8.15.2) with ESMTPS id w05Dn4kN055927 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Fri, 5 Jan 2018 20:49:04 +0700 (+07) (envelope-from eugen@grosbein.net) Subject: Re: svn commit: r327559 - in head: . sys/net To: Steven Hartland , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201801042005.w04K5liB049411@repo.freebsd.org> <5A4E9397.9000308@grosbein.net> <5A4EDC62.50508@grosbein.net> From: Eugene Grosbein Message-ID: <5A4F824C.1060405@grosbein.net> Date: Fri, 5 Jan 2018 20:49:00 +0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=2.2 required=5.0 tests=BAYES_00, LOCAL_FROM, RDNS_NONE autolearn=no autolearn_force=no version=3.4.1 X-Spam-Report: * -2.3 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * 2.6 LOCAL_FROM From my domains * 1.9 RDNS_NONE Delivered to internal network by a host with no rDNS X-Spam-Level: ** X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on hz.grosbein.net X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Jan 2018 13:49:32 -0000 05.01.2018 16:26, Steven Hartland пишет: > > On 05/01/2018 02:01, Eugene Grosbein wrote: >> 05.01.2018 4:52, Steven Hartland wrote: >> >>>> RSS by definition has meaning to received stream. What is "outbound" stream >>>> in this context, why can the hash calculatiom method change and what exactly >>>> does it mean "a stream being incorrectly split"? >>> Yes RSS is indeed a received stream but that is used by lagg for lacp and loadbalance protocols >>> to decide which port of the lagg to "send" the packet out of. >>> As the flowid is not known when a new "output" stream is instigated the current code >>> falls back to manual hash calculation to determine which port to send the initial packet from. >>> Once a response is received a tx then uses the flowid. >>> This change of hash calculation method can result in the initial packet being sent >>> from a different port than the rest of the stream; this is what I meant by "incorrectly split". >>> >>> See the following: >>> https://github.com/freebsd/freebsd/blob/master/sys/net/if_lagg.c#L2066 >>> https://github.com/freebsd/freebsd/blob/master/sys/net/ieee8023ad_lacp.c#L846 >> I still do not get what is "output stream" for you. >> >> If you are talking on forwarding (routing) transit packets at IP layer, >> they all have flowid from the beginning and first packet does not differ from others at all. > At the simplest level its a tcp stream that is started from the host. So given we have hostA (src) and hostB (dest), the output stream is one started by hostA with a destination of hostB where hostA is configured with lagg. > > In this case with use_flowid we've confirmed we get the following (the interfaces used vary per flow of cause): > hostA - SYN (ix0) -> hostB # Manual hash calculated > hostB - SYN,ACK (ix0) -> hostA# flowid used > hostA - ACK (ix1) -> hostB # flowid used > hostA - Data(ix1) -> hostB # flowid used > hostB - ACK (ix0) -> hostA # flowid used > ... > > Here hostA and hostB both had lagg0 comprising of ix0 and ix1. It should be: hostA - SYN (ix0) -> hostB # Manual hash (1) calculated hostB - SYN,ACK (ix0) -> hostA# hardware flowid (2) received hostA - ACK (ix1) -> hostB # Manual hash (1) calculated hostA - Data(ix1) -> hostB # hardware flowid (2 or 3) received hostB - ACK (ix0) -> hostA # Manual hash (1) calculated That is, there is no guarantee of persistance of flowid of incoming packets as they can be received with distinct ports of lagg being distinct hardware computing flowid differently. Some ports may not support RSS at all. We should not use incoming hardware flowid for anything by default in case of TCP. >> If you are talking on locally originated (not transit) data streem from local TCP socket >> being sent in response to corresponding incoming TCP segments, then these outgoing >> packets should have their own fixed flow id by default in case of LACP >> and thhis flow id should not depend on (possibly ever changing) flow id of incoming TCP segments. > Nope in this case we have all the information needed, but I don't believe we can't tell that's the case. >> If you insist that flow id of outgoing packets does depend on ever changing incoming packet's flow id, >> then this is the bug that should be fixed and not lagg's defaults. > As detailed above once the session is established then the flowid remains fixed. Why do you mix flowid of incoming stream with flowid of outgoing stream?