I believe I've found the fix for this issue for 3.13. If you can, please test the kernel posted on comment #1 on this bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1346917 Make sure KSM is enabled; and any workarounds for this bug are disabled.
If this fixes the issue for you, you are welcome to mark this bug as a duplicate of 1346917. Thanks! ** No longer affects: qemu (Ubuntu) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1341195 Title: KVM guests getting slow by time Status in “linux” package in Ubuntu: Incomplete Bug description: There is a post with very similar symptoms on serverfault: http://serverfault.com/questions/609881/windows-server-2012-on-kvm-on- ubuntu-14-04-runs-well-for-a-while-and-then-slows/612084#612084 Basically all kind of KVM guests are getting slow by time, both windows or linux. The more running guests, it happens sooner. Switching back to Saucy kernel is a good workaround. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: qemu-kvm 2.0.0+dfsg-2ubuntu1.1 ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2 Uname: Linux 3.13.0-29-generic x86_64 NonfreeKernelModules: zfs zunicode zavl zcommon znvpair ApportVersion: 2.14.1-0ubuntu3.2 Architecture: amd64 Date: Sat Jul 12 22:18:49 2014 SourcePackage: qemu UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1341195/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp