On Tue, 2014-04-08 at 16:49 -0400, Simon Chen wrote: > A little update on this.. > > I turned on multiqueue of vhost-net. Now the receiving VM is getting > traffic over all four queues - based on the CPU usage of the four > vhost-[pid] threads. For some reason, the sender is now pegging 100% > on one vhost-[pid] thread, although four are available. > Need to check how many vcpus does the sender use, multiqueue choose txq based on processor id. If only one vcpu is used, the result is expected. > Do I need to change anything inside of the VM to leverage all four TX > queues? I did do "ethtool -L eth0 combined 4" and that doesn't seem to > be sufficient. No need any other configurations. I don't do iperf, but I can easily make full usage of all queues when I start multiple sessions of netperf. btw. In my Xeon(R) CPU E5-2650 machine, I can easily get 15Gbps+ of VM to VM throughput without any optimization with net-next tree. > > Thanks. > -Simon > > > On Sun, Apr 6, 2014 at 3:03 PM, Simon Chen <simonchennj@xxxxxxxxx> wrote: > > Yes, I am aware of SR-IOV and its pros and cons.. I don't think > > OpenStack supports the orchestration very well at this point, and you > > lose the flexible filtering provided by iptables at hypervisor layer. > > > > At this point, I am trying to see how much throughput a more > > software-base solution can achieve. Like I said, I've seen people > > achieving 6Gbps+ VM to VM throughput using OpenVSwitch and VXLAN > > software tunneling. I am more curious to find out why my setup cannot > > do that... > > > > Thanks. > > > > On Sun, Apr 6, 2014 at 1:35 PM, Bronek Kozicki <brok@xxxxxxxxxxx> wrote: > >> On 06/04/2014 15:06, Simon Chen wrote: > >>> > >>> Hello, > >>> > >>> I am using QEMU 1.6.0 on Linux 3.10.21. My VMs are using vhost-net in > >>> a typical OpenStack setup: VM1->tap->linux > >>> bridge->OVS->host1->physical network->host2->OVS->linux > >>> bridge->tap->VM2. > >>> > >>> It seems that under heavy network load, the vhost-[pid] processes on > >>> the receiving side is using 100% CPU. The sender side has over 85% > >>> utilized. > >>> > >>> I am seeing unsatisfactory VM to VM network performance (using iperf > >>> 16 concurrent TCP connections, I can only get 1.5Gbps, while I've > >>> heard people got to over 6Gbps at least), and I wonder if it has > >>> something to do with vhost-net maxing out on CPU. If so, is there > >>> anything I can tune the system? > >> > >> > >> You could dedicate network card to your virtual machine, using PCI > >> passthrough. > >> > >> > >> B. > >> > >> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
