** Package changed: linux-lts-raring (Ubuntu) => linux-lts-trusty (Ubuntu)
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-lts-trusty in Ubuntu. https://bugs.launchpad.net/bugs/1497447 Title: cgroup cpuacct.stats underreports cpu usage Status in linux-lts-trusty package in Ubuntu: New Bug description: I've reproduced this in both 3.8 and 3.13.0-64.104 kernel versions, on both VirtualBox and in AWS. From doing some experiments, it seems like the more threads running in the cgroup, the more cpuacct.stats underreports. If I run this example with one thread, both top and cpuacct.stat report 100% cpu. To reproduce: Run this python script in the background: python << EOF import threading import time def do_it(): n = 0 while True: n += 1 for n in range(0, 15): t = threading.Thread(target=do_it) t.start() threading.Event().wait() EOF observe process CPU usage in top (depending on system ~80 - 120%) move into a cpuacct cgroup: cd /sys/fs/cgroup/cpuacct mkdir test echo [pid] > cgroup.procs Watch the change in cpuacct.stat: cat cpuacct.stat && sleep 1 && cat cpuacct.stat In my test top reported ~106% CPU while cpuacct.stat over 1 second reported .61 (61%) ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: linux-image-3.8.0-44-generic 3.8.0-44.66~precise1 ProcVersionSignature: Ubuntu 3.8.0-44.66~precise1-generic 3.8.13.25 Uname: Linux 3.8.0-44-generic x86_64 AlsaDevices: total 0 crw-rw---T 1 root audio 116, 1 Sep 16 07:46 seq crw-rw---T 1 root audio 116, 33 Sep 16 07:46 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.0.1-0ubuntu17.9 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 Date: Fri Sep 18 13:16:32 2015 HibernationDevice: RESUME=UUID=a9509269-b6ce-4739-b237-d1fc96077c82 InstallationMedia: Ubuntu-Server 12.04 LTS "Precise Pangolin" - Release amd64 (20120424.1) IwConfig: Error: [Errno 2] No such file or directory Lsusb: Error: command ['lsusb'] failed with exit code 1: unable to initialize libusb: -99 MachineType: innotek GmbH VirtualBox MarkForUpload: True PciMultimedia: ProcEnviron: TERM=xterm-256color PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 VESA VGA ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.8.0-44-generic root=/dev/mapper/hostname-root ro quiet RelatedPackageVersions: linux-restricted-modules-3.8.0-44-generic N/A linux-backports-modules-3.8.0-44-generic N/A linux-firmware 1.79.18 RfKill: Error: [Errno 2] No such file or directory SourcePackage: linux-lts-raring UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 12/01/2006 dmi.bios.vendor: innotek GmbH dmi.bios.version: VirtualBox dmi.board.name: VirtualBox dmi.board.vendor: Oracle Corporation dmi.board.version: 1.2 dmi.chassis.type: 1 dmi.chassis.vendor: Oracle Corporation dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr: dmi.product.name: VirtualBox dmi.product.version: 1.2 dmi.sys.vendor: innotek GmbH To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-trusty/+bug/1497447/+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
