Public bug reported: Hello,
I am experiencing a noticeable system slowdown since I upgraded from Xenial to Yakkety on several VM under XenServer 6.5 (fully patched). I understand it will be difficult for me to describe what is happening and for you to troubleshoot this issue but I'll try to do my best. Just after booting the machine is pretty responsive but after some time it starts responding very slowly. Bash autocompletion for file paths takes 1-2 seconds to respond, commands as "host" take hundred of milliseconds consuming hundred of ms of CPU. Compiling is an order of magnitude slower, etc. I wasn't able to detect what is causing the slowness. I tried to strace slow process with no evident cause. It does not seem to be something I/O bound. I ran "host" in an infinite loop causing 100% CPU usage seen from XenServer, 100% CPU usage in top but the sum of CPU usage from the processes is under 10%. top - 00:51:48 up 1 day, 4:49, 3 users, load average: 1.47, 1.02, 0.59 Tasks: 144 total, 2 running, 142 sleeping, 0 stopped, 0 zombie %Cpu(s): 74.4 us, 24.4 sy, 0.0 ni, 1.1 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 4044600 total, 1719740 free, 843100 used, 1481760 buff/cache KiB Swap: 2095100 total, 2095100 free, 0 used. 3139664 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 30968 yggdra 20 0 13460 696 616 R 5.8 0.0 0:00.18 host 28790 root 20 0 42020 3748 3104 R 0.6 0.1 0:02.47 top [...] I downgraded to the last Xenial kernel and the issue disappeared. I now have two VMs, with the same configuration, both yakkety, one with kernel 4.8.0-26-generic and one with 4.4.0-45-generic, on the same XenServer host. Here is what I see running host: -------- 4.4.0-45 ---------------- $ time host www.google.com www.google.com has address 216.58.198.4 www.google.com has IPv6 address 2a00:1450:4002:801::2004 real 0m0.051s user 0m0.032s sys 0m0.016s -------- 4.8.0-26 --------------- $ time host www.google.com www.google.com has address 216.58.198.4 www.google.com has IPv6 address 2a00:1450:4002:801::2004 real 0m0.412s user 0m0.296s sys 0m0.096s I have other yakkety hosts on VMware and even on another XenServer 7.0 with no noticeable issues, it just seems to happen on this cluster. In the next days I will upgrade this cluster to XenServer 7.0 and I will update the bug telling if the hypervisor version is a factor. ProblemType: Bug DistroRelease: Ubuntu 16.10 Package: linux-image-4.8.0-26-generic 4.8.0-26.28 ProcVersionSignature: Ubuntu 4.8.0-26.28-generic 4.8.0 Uname: Linux 4.8.0-26-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Oct 27 20:02 seq crw-rw---- 1 root audio 116, 33 Oct 27 20:02 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.20.3-0ubuntu8 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: Date: Sat Oct 29 00:37:00 2016 HibernationDevice: RESUME=UUID=4ab77eb2-d96a-42d5-be31-b4d499646269 InstallationDate: Installed on 2011-09-19 (1866 days ago) InstallationMedia: Ubuntu-Server 11.10 "Oneiric Ocelot" - Beta amd64 (20110901) IwConfig: lo no wireless extensions. eth1 no wireless extensions. eth0 no wireless extensions. JournalErrors: Error: command ['journalctl', '-b', '--priority=warning', '--lines=1000'] failed with exit code 1: Hint: You are currently not seeing messages from other users and the system. Users in the 'systemd-journal' group can see all messages. Pass -q to turn off this notice. No journal files were opened due to insufficient permissions. Lsusb: Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub MachineType: Xen HVM domU PciMultimedia: ProcFB: 0 cirrusdrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-26-generic root=UUID=0c869ff8-8fe7-41b9-89f3-9da4882b4e87 ro init=/lib/systemd/systemd RelatedPackageVersions: linux-restricted-modules-4.8.0-26-generic N/A linux-backports-modules-4.8.0-26-generic N/A linux-firmware 1.161 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: Upgraded to yakkety on 2016-10-14 (14 days ago) WifiSyslog: dmi.bios.date: 09/30/2016 dmi.bios.vendor: Xen dmi.bios.version: 4.4.1-xs129783 dmi.chassis.type: 1 dmi.chassis.vendor: Xen dmi.modalias: dmi:bvnXen:bvr4.4.1-xs129783:bd09/30/2016:svnXen:pnHVMdomU:pvr4.4.1-xs129783:cvnXen:ct1:cvr: dmi.product.name: HVM domU dmi.product.version: 4.4.1-xs129783 dmi.sys.vendor: Xen ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug yakkety -- 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/1637666 Title: Heavy system slowdown with 4.8.0 kernel under XenServer Status in linux package in Ubuntu: New Bug description: Hello, I am experiencing a noticeable system slowdown since I upgraded from Xenial to Yakkety on several VM under XenServer 6.5 (fully patched). I understand it will be difficult for me to describe what is happening and for you to troubleshoot this issue but I'll try to do my best. Just after booting the machine is pretty responsive but after some time it starts responding very slowly. Bash autocompletion for file paths takes 1-2 seconds to respond, commands as "host" take hundred of milliseconds consuming hundred of ms of CPU. Compiling is an order of magnitude slower, etc. I wasn't able to detect what is causing the slowness. I tried to strace slow process with no evident cause. It does not seem to be something I/O bound. I ran "host" in an infinite loop causing 100% CPU usage seen from XenServer, 100% CPU usage in top but the sum of CPU usage from the processes is under 10%. top - 00:51:48 up 1 day, 4:49, 3 users, load average: 1.47, 1.02, 0.59 Tasks: 144 total, 2 running, 142 sleeping, 0 stopped, 0 zombie %Cpu(s): 74.4 us, 24.4 sy, 0.0 ni, 1.1 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 4044600 total, 1719740 free, 843100 used, 1481760 buff/cache KiB Swap: 2095100 total, 2095100 free, 0 used. 3139664 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 30968 yggdra 20 0 13460 696 616 R 5.8 0.0 0:00.18 host 28790 root 20 0 42020 3748 3104 R 0.6 0.1 0:02.47 top [...] I downgraded to the last Xenial kernel and the issue disappeared. I now have two VMs, with the same configuration, both yakkety, one with kernel 4.8.0-26-generic and one with 4.4.0-45-generic, on the same XenServer host. Here is what I see running host: -------- 4.4.0-45 ---------------- $ time host www.google.com www.google.com has address 216.58.198.4 www.google.com has IPv6 address 2a00:1450:4002:801::2004 real 0m0.051s user 0m0.032s sys 0m0.016s -------- 4.8.0-26 --------------- $ time host www.google.com www.google.com has address 216.58.198.4 www.google.com has IPv6 address 2a00:1450:4002:801::2004 real 0m0.412s user 0m0.296s sys 0m0.096s I have other yakkety hosts on VMware and even on another XenServer 7.0 with no noticeable issues, it just seems to happen on this cluster. In the next days I will upgrade this cluster to XenServer 7.0 and I will update the bug telling if the hypervisor version is a factor. ProblemType: Bug DistroRelease: Ubuntu 16.10 Package: linux-image-4.8.0-26-generic 4.8.0-26.28 ProcVersionSignature: Ubuntu 4.8.0-26.28-generic 4.8.0 Uname: Linux 4.8.0-26-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Oct 27 20:02 seq crw-rw---- 1 root audio 116, 33 Oct 27 20:02 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.20.3-0ubuntu8 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: Date: Sat Oct 29 00:37:00 2016 HibernationDevice: RESUME=UUID=4ab77eb2-d96a-42d5-be31-b4d499646269 InstallationDate: Installed on 2011-09-19 (1866 days ago) InstallationMedia: Ubuntu-Server 11.10 "Oneiric Ocelot" - Beta amd64 (20110901) IwConfig: lo no wireless extensions. eth1 no wireless extensions. eth0 no wireless extensions. JournalErrors: Error: command ['journalctl', '-b', '--priority=warning', '--lines=1000'] failed with exit code 1: Hint: You are currently not seeing messages from other users and the system. Users in the 'systemd-journal' group can see all messages. Pass -q to turn off this notice. No journal files were opened due to insufficient permissions. Lsusb: Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub MachineType: Xen HVM domU PciMultimedia: ProcFB: 0 cirrusdrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-26-generic root=UUID=0c869ff8-8fe7-41b9-89f3-9da4882b4e87 ro init=/lib/systemd/systemd RelatedPackageVersions: linux-restricted-modules-4.8.0-26-generic N/A linux-backports-modules-4.8.0-26-generic N/A linux-firmware 1.161 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: Upgraded to yakkety on 2016-10-14 (14 days ago) WifiSyslog: dmi.bios.date: 09/30/2016 dmi.bios.vendor: Xen dmi.bios.version: 4.4.1-xs129783 dmi.chassis.type: 1 dmi.chassis.vendor: Xen dmi.modalias: dmi:bvnXen:bvr4.4.1-xs129783:bd09/30/2016:svnXen:pnHVMdomU:pvr4.4.1-xs129783:cvnXen:ct1:cvr: dmi.product.name: HVM domU dmi.product.version: 4.4.1-xs129783 dmi.sys.vendor: Xen To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1637666/+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