Date: Tue, 25 Jun 2019 17:01:24 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= <roger.pau@citrix.com> To: Roger Pau =?utf-8?B?TW9ubsOp?= <roger.pau@citrix.com> Cc: Christian M <christian.marcos@gmail.com>, <freebsd-xen@freebsd.org>, <freebsd-net@freebsd.org> 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 Message-ID: <20190625150124.wiqikig623k3lzuv@MacBook-Air-de-Roger.local> In-Reply-To: <20190625145643.shasw7bcgu6s2hg7@MacBook-Air-de-Roger.local> References: <mailman.7.1560945600.15387.freebsd-xen@freebsd.org> <12994df1-f847-ec92-aae8-43a32e59385f@darco.dk> <CAKwR994kQTRfB0R0_WiTYx4pgOHtR-ge7h0vP8NiM_%2B-MBPGGw@mail.gmail.com> <20190625082103.qiiz2cikrauaqlas@MacBook-Air-de-Roger.local> <CAKwR996s9Y_Bea95GOhPkdEJabmJM0r6Qi43gW7_8SXE2ryddA@mail.gmail.com> <20190625145643.shasw7bcgu6s2hg7@MacBook-Air-de-Roger.local>
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There's a mistake in my reply below. On Tue, Jun 25, 2019 at 04:56:43PM +0200, Roger Pau Monné wrote: > On Tue, Jun 25, 2019 at 01:55:40PM +0200, Christian M wrote: > > I've made two tests while running tcpdump on the xcp-ng host. I'm not at > > all qualified to interpret the .pcap files from tcpdump, but I've put them > > on Google Drive and linked them below the two tests. Perhaps someone more > > qualified could have a look for anything useful in there. Please note the > > extremely uneven throughput for test 2 below. It's almost like the > > throughput increased when running tcpdump simultaneously. > > > > Host: XCP-ng 7.6.0 > > Network: Private Network on host, not connected to any PIF. > > VM1: 12.0-RELEASE (1 VIF, 172.31.16.125) > > VM2: 12.0-RELEASE (1 VIF, 172.31.15.126) > > > > On the host I listen with tcpdump on the VIF for VM1 in both tests. > > > > VM1 as client: > > > > On XCP-ng: tcpdump -i vif42.0 -s 0 -w xcp-ng-vm1-client.pcap > > Can you check the capabilities of vif42.0? (ie: whether csum > offloading is actually disabled on the host?) > > > xcp-ng-vm1-client.pcap (80M): > > https://drive.google.com/open?id=1eR3fetvKRz3vFSXCxDKuJYFrQ3wLqjrU > > On VM1: iperf3 -c 172.31.16.126 > > On VM2: iperf3 -s > > I've taken a look at the dump and the checksum is wrong (or maybe > missing) for all? packets. > > Packets with source 172.31.16.125 all have the TCP checksum set to > 0x7f80 and all packets with source 172.31.16.125 have the TCP checksum ^ 172.31.16.126
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