Tested with kernel - Linux 3.15.0-031500rc7-generic After 24 hours there's no sign of the problem.
After watching numastat for a while I noticed that with the 3.13.0 kernel the allocated memory for qemu does a really sudden drop from 6GB down to 2GB. QEMU then freezes with 100% CPU until the allocation goes back up to 6GB again. On 3.15 the memory stays almost constant and is migrated towards one numa node as you'd expect. Just speculating but there must be some kind of page invalidation bug in the numa balancer. -- 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/1322441 Title: QEMU Windows guest unstable after random amount of time Status in “linux” package in Ubuntu: Incomplete Bug description: Ubuntu 14.04, all updates done as of 23/5/2014 Kernel : Linux 3.13.0-24-generic Qemu : 1.7.1 and 2.0.0 tested Tested using both Xeon 5620 and 5520 processors, 48GB RAM. Anywhere from 20 minutes for 3+ hours after booting Windows guests become unstable. Guest appear to freeze intermittently (VNC console unresponsive, network pings dropped to guest, frozen IO) for 20-60 seconds at a time which repeats constantly every few minutes and guests do not recover unless QEMU is killed and the guest is started again. Whilst the guest is frozen CPU usage of the QEMU process jumps to 100-150%. WORKAROUND: Disable automatic NUMA balancing: echo 0 > /proc/sys/kernel/numa_balancing --- AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 May 24 01:25 seq crw-rw---- 1 root audio 116, 33 May 24 01:25 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.14.1-0ubuntu3.1 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: Error: [Errno 2] No such file or directory DistroRelease: Ubuntu 14.04 HibernationDevice: RESUME=UUID=38dc08b6-55f7-482d-8f82-f048b3dbad56 InstallationDate: Installed on 2013-03-21 (428 days ago) InstallationMedia: Ubuntu-Server 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120817.3) MachineType: Supermicro X8DTT Package: linux (not installed) PciMultimedia: ProcFB: 0 VESA VGA ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-24-generic root=UUID=386ad1f0-7ced-414f-9a09-4c078c36977c ro nomdmonddf nomdmonisw nomdmonddf nomdmonisw ProcVersionSignature: Ubuntu 3.13.0-24.47-generic 3.13.9 RelatedPackageVersions: linux-restricted-modules-3.13.0-24-generic N/A linux-backports-modules-3.13.0-24-generic N/A linux-firmware 1.127.2 RfKill: Error: [Errno 2] No such file or directory Tags: trusty Uname: Linux 3.13.0-24-generic x86_64 UpgradeStatus: Upgraded to trusty on 2014-05-21 (2 days ago) UserGroups: _MarkForUpload: True dmi.bios.date: 05/20/2010 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 080016 dmi.board.asset.tag: 1234567890 dmi.board.name: X8DTT dmi.board.vendor: Supermicro dmi.board.version: 2.0 dmi.chassis.asset.tag: To Be Filled By O.E.M. dmi.chassis.type: 17 dmi.chassis.vendor: Supermicro dmi.chassis.version: 1234567890 dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr080016:bd05/20/2010:svnSupermicro:pnX8DTT:pvr1234567890:rvnSupermicro:rnX8DTT:rvr2.0:cvnSupermicro:ct17:cvr1234567890: dmi.product.name: X8DTT dmi.product.version: 1234567890 dmi.sys.vendor: Supermicro To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1322441/+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