[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] PCI passthrough, poor network performance in upload direction
On Thu, Dec 11, 2008 at 4:10 PM, Luis F Urrea <lfurrea@xxxxxxxxx> wrote: > Hi all, > > I have been having an issue for over a year with several Xen installations > and have not been able to find out if this is just something I am missing. > > Basically I am trying to configure a firewall with two ethernet cards in a > domU using pci passthrough. I am hiding the Ethernet cards at boot time via > the pciback.hide kernel option. > > Right now I am running Xen 3.3.0 and the two Ethernet cards are passed to > the FW domU. > > The FW domU is not configured with a vif interface to the bridge, so > basically communication with DomO passes through the external hardware. > > Tests using iperf show me that download bandwidth from the FW domU to an > external machine connected to the switch go as high as 94 Mbits/sec. However > upload bandwidth from a laptop to the domU give me a maximum of 574 > Kbits/sec which basically is not enough to cover the upload bw of some > internet connections. > > I have read recommendations about using ethtool -K ethX tx off in dom U, but > in this case the tx ring does not seem the be the issue since the download > speeds are just fine. Using 'ethtool -K rx eth0 off' did not show any > improvements. > > Since the guest domain has exclusive access to both Ethernet cards I suppose > that the overhead is introduced somewhere in the domU's kernel but I > wouldn't exactly know where else to look for a possible fix. > > Your input is appreciated. > What is your guest kernel? Is this all PV? What is your hardware (both NIC and system)? What driver is the guest using for the device? Cheers, Todd -- Todd Deshane http://todddeshane.net http://runningxen.com _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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