Public bug reported: Binary package hint: kvm
Description of problem: Guest kernel can't read TSC frequency from the hypervisor on hardy and interpid causing unstable TSC clocksource even if host has constant_tsc processor flag. This causes clock drifting on high load and freezing of guests with more than one cpu. How reproducible: Easily Steps to Reproduce: 1. Boot host kernel with clocksource=tsc 2. Boot guest kernel with clocksource=tsc 3. dmesg | egrep "(tsc|TSC)" on guest Actual results: Hardy: kernel version 2.6.24-24.53 [8739129.899892] Time: tsc clocksource has been installed. [8739131.245835] Clocksource tsc unstable (delta = 144317765 ns) Interpid: kernel version: 2.6.27-14.41 [ 0.000000] TSC: Unable to calibrate against PIT [ 0.000000] TSC: using PMTIMER reference calibration Expected results: kernel should read frequency from the hypervisor that results in stable TSC clocksource. Aditional info: I have tried this on jaunty host, but i'm not really sure if that matters, since the hypervisor supports it. Tried with CentOS 5.3, 2.6.18-164.el5 kernel and worked as expected. relevant dmesg part from CentOS: kvm_get_tsc_khz: cpu 0, msr 0:1101001 TSC: Frequency read from the hypervisor Time: tsc clocksource has been installed. ** Affects: kvm (Ubuntu) Importance: Undecided Status: New ** Tags: clocksouce kvm tsc -- Guest kernel can't read TSC frequency from the hypervisor https://bugs.launchpad.net/bugs/444531 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to kvm in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs