** Tags added: canonical-bootstack -- 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/1759787
Title: Very inaccurate TSC clocksource with kernel 4.13 on selected CPUs Status in linux package in Ubuntu: Triaged Status in linux source package in Artful: Won't Fix Bug description: On kernel 4.13.0-37-generic, HP ProLiant DL380 Gen10 systems have been observed with very large clock offsets, as measured by NTP. Over the past few days on one of our production systems, we've used 3 different kernels: https://pastebin.ubuntu.com/p/nDkkgRqdtv/ All of these kernels default to the TSC clocksource, which is supposed to be very reliable on Skylake-X CPUs. On 4.4 (linux-image-generic- lts-xenial) it works as expected; on 3.13 (trusty default kernel) it works a little worse, and on 4.13 (linux-image-generic-hwe-16.04) it is much worse. Today I switched 4.13 from the TSC clocksource to the HPET clocksource and it improved the situation dramatically. I've produced loopstats & peerstats graphs from NTP corresponding to the dates in the pastebin above and placed them at https://people.canonical.com/~paulgear/ntp/. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-4.13.0-37-generic 4.13.0-37.42 ProcVersionSignature: User Name 4.13.0-37.42~16.04.1-generic 4.13.13 Uname: Linux 4.13.0-37-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Mar 27 18:26 seq crw-rw---- 1 root audio 116, 33 Mar 27 18:26 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.14.1-0ubuntu3.27 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: CurrentDmesg: [ 6280.259121] perf: interrupt took too long (2505 > 2500), lowering kernel.perf_event_max_sample_rate to 79750 [10463.378558] perf: interrupt took too long (3133 > 3131), lowering kernel.perf_event_max_sample_rate to 63750 [32314.949747] perf: interrupt took too long (4000 > 3916), lowering kernel.perf_event_max_sample_rate to 50000 [129804.100274] clocksource: Switched to clocksource hpet [132747.312089] perf: interrupt took too long (5004 > 5000), lowering kernel.perf_event_max_sample_rate to 39750 Date: Thu Mar 29 07:45:22 2018 IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 002: ID 0bda:0329 Realtek Semiconductor Corp. Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 002: ID 0424:2660 Standard Microsystems Corp. Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: HPE ProLiant DL380 Gen10 PciMultimedia: ProcFB: 0 mgadrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-37-generic root=UUID=b33fdcbd-a949-41a0-86d2-03d0c6808284 ro console=tty0 console=ttyS0,115200 RelatedPackageVersions: linux-restricted-modules-4.13.0-37-generic N/A linux-backports-modules-4.13.0-37-generic N/A linux-firmware 1.127.24 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) WifiSyslog: dmi.bios.date: 02/15/2018 dmi.bios.vendor: HPE dmi.bios.version: U30 dmi.board.name: ProLiant DL380 Gen10 dmi.board.vendor: HPE dmi.chassis.type: 23 dmi.chassis.vendor: HPE dmi.modalias: dmi:bvnHPE:bvrU30:bd02/15/2018:svnHPE:pnProLiantDL380Gen10:pvr:rvnHPE:rnProLiantDL380Gen10:rvr:cvnHPE:ct23:cvr: dmi.product.family: ProLiant dmi.product.name: ProLiant DL380 Gen10 dmi.sys.vendor: HPE To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1759787/+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
