Hi all, I have problem reaching 1Gbps network speed with dom0 / domU (paravirtualized) on my centos5 installations.
The fastest speed I measured in domU was about 800/600 receive/transmit Mbps, dom0 being a bit slower. I'm using bridging (eeither with default xen/centos network-bridge script or with my own scripts assigning vlans to bridges).
Is anyone experiencing same network slowdown? Or could it be just some configuration issue on my side?
Thanks,
david.kostal@gmail.com ----+
I have not had the opportunity to test, but it sounds like expected behavior due how I/O is handled within Xen. It's a know fact that disc I/O is slow so I would expect the same for network I/O.
- Nicolas
On Nov 23, 2007 2:02 PM, David Kostal david.kostal@gmail.com wrote:
Hi all, I have problem reaching 1Gbps network speed with dom0 / domU (paravirtualized) on my centos5 installations.
The fastest speed I measured in domU was about 800/600 receive/transmit Mbps, dom0 being a bit slower. I'm using bridging (eeither with default xen/centos network-bridge script or with my own scripts assigning vlans to bridges).
Is anyone experiencing same network slowdown? Or could it be just some configuration issue on my side?
Thanks,
david.kostal@gmail.com ----+ _______________________________________________ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
David Kostal wrote:
Hi all, I have problem reaching 1Gbps network speed with dom0 / domU (paravirtualized) on my centos5 installations.
The fastest speed I measured in domU was about 800/600 receive/transmit Mbps, dom0 being a bit slower. I'm using bridging (eeither with default xen/centos network-bridge script or with my own scripts assigning vlans to bridges).
Is anyone experiencing same network slowdown? Or could it be just some configuration issue on my side?
What do you get on the same hardware running a non-Xen kernel? What does the test look like? You also have to consider that Ethernet is not 100% efficient.
Hi,
Is anyone experiencing same network slowdown? Or could it be just some configuration issue on my side?
What do you get on the same hardware running a non-Xen kernel? What does the test look like? You also have to consider that Ethernet is not 100% efficient.
The same hw without Xen can handle several 1Gbps (tested with 2) simultaneous streams (doesn't matter whether in- or out-going).
I think this is really Xen (vif-eth) speed issue which may or may not be possible to optimize, as there is really a lot of additional packet copying in the dom0 (and also domU is applicable).
So my question is more like - is there anyone who can get 1Gbps throuput on domU (or Dom0) eth0 under Xen?
Or do I have to assign the network card HW directly to the dom0/domU where I need full network speed?
Thanks,
david.kostal@gmail.com ----+
Hi all, so if anyone encounters this issue, there is some hint:)
So my question is more like - is there anyone who can get 1Gbps throuput on domU (or Dom0) eth0 under Xen?
Or do I have to assign the network card HW directly to the dom0/domU where I need full network speed?
It seems that for DomU there must be dedicated NIC assigned to each guest to reach 1Gbps (or more).
For Dom0 the solution is to simply forget about vethX/vif0.X pairs and assign the IP of dom0 directly to bridge device (if you use bridging). Than everything's fast again.
david.kostal@gmail.com ----+
-
Christopher G. Stach II -
David Kostal -
Nicolas Sahlqvist