https://bugzilla.kernel.org/show_bug.cgi?id=55061 Summary: cpu stats reported in cgroup file is erroneous Product: Virtualization Version: unspecified Kernel Version: 3.5.3-1.fc17.i686.PAE Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: high Priority: P1 Component: kvm AssignedTo: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx ReportedBy: roopagovind@xxxxxxxxx Regression: No While testing the virsh cpu-stats functionality, I found that the stats reported in the command output is incorrect, specifically the reported user time and system time. Please find a sample output. virsh cpu-stats fedora-18 --total --start 0 --count 4 CPU0: cpu_time 15.321903938 seconds CPU1: cpu_time 11.410812819 seconds CPU2: cpu_time 2.948269295 seconds CPU3: cpu_time 1.724287630 seconds Total: cpu_time 31.405273682 seconds user_time 1.310000000 seconds system_time 12.860000000 seconds As you can see here, the user time is less than system_time which is incorrect. As an experiment, I tried running a while 1 loop inside this guest and observed that stats for a period of time was not changing appropriately or rather not the expected way. While the while 1 loop was running inside the guest, the user_time continued to be less than system_time which is incorrect. More over the guest is not running any workload expect this while 1 loop. So definitely there seems to be a bug in the cgroup accounting of cpu stats. Please fix this cgroup bug. I've verified this against different distro versions and flavors and hit the same issue across all these test environments. --roopa -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
