Quoting from: man time "... ACCURACY The elapsed time is not collected atomically with the execution of the program; as a result, in bizarre circumstances (if the time command gets stopped or swapped out in between when the program being timed exits and when time calculates how long it took to run), it could be much larger than the actual execution time.
When the running time of a command is very nearly zero, some values (e.g., the percentage of CPU used) may be reported as either zero (which is wrong) or a question mark. Most information shown by time is derived from the wait3(2) system call. The numbers are only as good as those returned by wait3(2). On systems that do not have a wait3(2) call that returns status information, the times(2) system call is used instead. However, it provides much less information than wait3(2), so on those systems time reports the majority of the resources as zero. The `%I' and `%O' values are allegedly only `real' input and output and do not include those supplied by caching devices. The meaning of `real' I/O reported by `%I' and `%O' may be muddled for workstations, especially diskless ones. ..." ** Tags removed: time ** Changed in: linux (Ubuntu) Status: Confirmed => Invalid -- 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/675469 Title: System timer functionalities Status in “linux” package in Ubuntu: Invalid Bug description: I use to measure time using the getrusage() function in my C/C++ code and, suddenly, perfectly working code with previous releases of the kernel did not work anymore with kernel 2.6.32-25 ; The bug extends to the shell command "time". Its effect is that user time cannot pass a given threshold, around 261.8s, the rest of the running time of a process being counted as system time. ProblemType: Bug DistroRelease: Ubuntu 10.04 Package: linux-headers-2.6.32-25 2.6.32-25.45 Regression: Yes Reproducible: Yes ProcVersionSignature: Ubuntu 2.6.32-24.43-generic 2.6.32.15+drm33.5 Uname: Linux 2.6.32-24-generic i686 AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21. Architecture: i386 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 0: Intel [HDA Intel], device 0: STAC92xx Analog [STAC92xx Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: jermann-c 2110 F.... pulseaudio CRDA: Error: [Errno 2] Aucun fichier ou dossier de ce type Card0.Amixer.info: Card hw:0 'Intel'/'HDA Intel at 0xfe9fc000 irq 21' Mixer name : 'SigmaTel STAC9205' Components : 'HDA:838476a0,102801f9,00100204 HDA:14f12c06,14f1000f,00100000' Controls : 19 Simple ctrls : 11 Date: Mon Nov 15 11:08:30 2010 HibernationDevice: RESUME=UUID=8d4f1ec4-764d-4ad5-a6b1-cad44b9861b0 InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5) MachineType: Dell Inc. Latitude D630 PackageArchitecture: all PccardctlIdent: Socket 0: no product info available PccardctlStatus: Socket 0: no card ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-24-generic root=UUID=30ea42a4-6eca-4b4f-bc65-2b4e23e79ab4 ro quiet splash ProcEnviron: PATH=(custom, user) LANG=fr_FR.utf8 SHELL=/bin/bash RelatedPackageVersions: linux-firmware 1.34.1 SourcePackage: linux dmi.bios.date: 06/20/2008 dmi.bios.vendor: Dell Inc. dmi.bios.version: A12 dmi.board.name: 0KU184 dmi.board.vendor: Dell Inc. dmi.chassis.type: 8 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA12:bd06/20/2008:svnDellInc.:pnLatitudeD630:pvr:rvnDellInc.:rn0KU184:rvr:cvnDellInc.:ct8:cvr: dmi.product.name: Latitude D630 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/675469/+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