Date: Wed, 25 Jan 2012 18:02:04 +0100 From: "laurent.cligny@gmail.com" <laurent.cligny@gmail.com> To: Ivan Ivanyuk <ivan.ivanyuk@gmail.com> Cc: freebsd-xen@freebsd.org Subject: Re: [FreeBSD 8.2 amd64 XENHVM] Incorrect behavior of xen networking drivers: unexpected tcp reassembling Message-ID: <4F20358C.6070805@gmail.com> In-Reply-To: <CAD_Den-Pd%2Bd7hNGFeuqmuFG6Ut7vWZZoUSNf2DB7A%2BjMFLBNcg@mail.gmail.com> References: <CAD_Den-o6rN4uarRrRpPrdzjX30kSJjrO%2BquTmZQ6cqokTrYFw@mail.gmail.com> <CAD_Den-Pd%2Bd7hNGFeuqmuFG6Ut7vWZZoUSNf2DB7A%2BjMFLBNcg@mail.gmail.com>
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Le 12/01/2012 19:42, Ivan Ivanyuk a écrit : > On 12 January 2012 00:35, Ivan Ivanyuk <ivan.ivanyuk@gmail.com> wrote: >> Hi All, Hi Ivan, >> I can get about 500Mb/s from virtual machine to external host, but >> only 200Kb/s from any internal PC to the same external host through >> virtual machine router. >> >> Closest description I found in archives is this: >> http://lists.freebsd.org/pipermail/freebsd-xen/2011-May/000902.html. >> I'm the one who had that problem and tried to explain it. I must say that you explained it much better, so hopefully this issue will be understandable to everyone ;) > Somewhat successful follow-up: > > There is still some occurrences of reordered packets but original > issue was resolved. > > Turned out this mechanism can be turned off by "ifconfig -lro" in > FreeBSD itself. I'm not sure if turning LRO on virtual driver by > default is good idea at all, but obviously LRO implementation for xn > device doesn't consider DF flag implication on resulting packets. > > I'm not familiar with other LRO algorithms which used in physical > NIC's. Can someone comment if such problem is normal for it? > > And what is your opinion on using tso, rxcsum and txcsum offloads in > virtual envirnoment? > Glad to know you almost addressed the issue with custom settings. I think I would try again any time soon, to see if I can work with it in production environment. Because of this issue I had to run a Linux/debian vhost in place of FreeBSD, and I would know if anyone had bandwidth problems with this kind of setup under the brand new FreeBSD 9.0 ? I would like to be able to use PF and ALTQ at my gateway for a long time, and this issue was the only show-stopper I felt into. Regards, Laurent Cligny
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