From owner-freebsd-net@freebsd.org Wed Jun 26 08:37:24 2019 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C129515C082D; Wed, 26 Jun 2019 08:37:24 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from eg.sd.rdtc.ru (eg.sd.rdtc.ru [IPv6:2a03:3100:c:13::5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "eg.sd.rdtc.ru", Issuer "eg.sd.rdtc.ru" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id C55879360D; Wed, 26 Jun 2019 08:37:13 +0000 (UTC) (envelope-from eugen@grosbein.net) X-Envelope-From: eugen@grosbein.net X-Envelope-To: freebsd-xen@freebsd.org Received: from [10.58.0.4] ([10.58.0.4]) by eg.sd.rdtc.ru (8.15.2/8.15.2) with ESMTPS id x5Q8aoVt005684 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Wed, 26 Jun 2019 15:36:50 +0700 (+07) (envelope-from eugen@grosbein.net) Subject: Re: Very slow and inconsistent internal network speed (between, VM's on the same host) for FreeBSD 11.0+ as guest on, XCP-ng/XenServer To: Christian M References: <12994df1-f847-ec92-aae8-43a32e59385f@darco.dk> <20190625082103.qiiz2cikrauaqlas@MacBook-Air-de-Roger.local> <8ec84f75-2100-ff8a-6337-3c955f31da62@grosbein.net> Cc: freebsd-xen@freebsd.org, freebsd-net@freebsd.org From: Eugene Grosbein Message-ID: Date: Wed, 26 Jun 2019 15:36:42 +0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: C55879360D X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; spf=permerror (mx1.freebsd.org: domain of eugen@grosbein.net uses mechanism not recognized by this client) smtp.mailfrom=eugen@grosbein.net X-Spamd-Result: default: False [-0.01 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.80)[-0.801,0]; MX_INVALID(0.50)[greylisted]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; NEURAL_HAM_LONG(-0.15)[-0.150,0]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[grosbein.net]; NEURAL_SPAM_SHORT(0.48)[0.485,0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; R_SPF_PERMFAIL(0.00)[]; IP_SCORE(0.05)[asn: 29072(0.26), country: RU(0.01)]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:29072, ipnet:2a03:3100::/32, country:RU]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jun 2019 08:37:24 -0000 26.06.2019 15:11, Christian M wrote: > Running tcpdump on the host while running iperf3 between the 12.0 VM's > results in a lot of incorrect cksum like this. > > tcpdump -i vif54.0 -v -nn| grep -i incorrect > 172.31.16.125.63013 > 172.31.16.126.5201: Flags [.], cksum 0x7f08 > (incorrect -> 0x030f), seq 223153882:223155330, ack 1, win 1026, options > [nop,nop,TS val 4104002274 ecr 3926764642], length 1448 Incorrect checksum shown by tcpdump is normal and expected for outgoing packets if txcsum offload is not disabled because networking stack skips checksum calculation offloading it to "hardware". It still indicates a bug at sending side if seen for outgoing packets when txcsum is disabled. Incorrect checksum shown by tcpdump for incoming packets always indicates a problem at sending side or intermediate network (if any). You should check output of "netstat -sp ip" and "netstat -sp tcp" for non-zero and growing checksum error counters at receiving side.