On 05/23/13 07:02, Jay West wrote: > Environment is Citrix Xenserver Advanced, with (mostly) freebsd 9.1 64bit > HVM with PV drivers. > > I've heard much mention around the net that in pretty much all cases, TCP > offloading should be disabled inside the VM. I have also seen other posts > that TCP offloading should be disabled on the Dom0. > > So my question is; for best performance should TCP offloading be disabled in > the VM, or the Xenserver (dom0), or should it be disabled in BOTH?
There's an incompatibility between FreeBSD's TCP stack, TSO, and the Linux Xen netback driver: With TSO enabled on netfront, we can generate longer mbuf chains than the Linux netback is able to handle. I have an ugly patch for this on EC2, but andre will be fixing this better in the near future. For now I recommend # ifconfig xn0 -tso unless you need multi-Gbps networking performance. -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "[email protected]"
