Public bug reported: If running a box with multiple CPU sockets and Ubuntu 14.04 Server 64-bit qemu-kvm with KSM enabled as by default, random high latency occurs on network connections for VMs, as high as 4000ms - 5000ms. The host also reports high IO wait times.
Disabling KSM fixed this for me. I run the same setup on boxes with only 1 CPU socket and it's not an issue. qemu-kvm version: Installed: 2.0.0+dfsg-2ubuntu1.3 ** Affects: qemu-kvm (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to qemu-kvm in Ubuntu. https://bugs.launchpad.net/bugs/1368439 Title: Random high latency with KSM enabled and multiple CPU sockets To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/1368439/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs