Unexpected Clocksource tsc unstable message, freezes system

Posted on 2008-10-14
Medium Priority
Last Modified: 2013-12-06
On one of my machines (Virtual machine running Debian on VMWare ESX OS), I unexpectedly got: "Clocksource tsc unstable (detlta = 4689558902 ns)" on my console.

I was able to get a login prompt with SSH, but after entering the username, the system freezes.

Resetting the VM in the VMWare console restored the VM to normal behaviour, but i would like to a) understand the error message and b) prevent it from happening again.

Can anybody shed some light on this for me? Using kernel 2.6.22-2-686 from the SID distribution, its a high volume production mail server. Some updates have been performed today but nothing really comes to mind that could be the culprit. Could it be a change on the VM host?
Question by:Xyptilon2
LVL 17

Accepted Solution

owensleftfoot earned 2000 total points
ID: 22712096
TSC=Time Stamp Counter. Processors have dynamically changed clock speed (ofc to save power). The TSC is supposed to tick at the CPU rate (unless it's a constant_tsc, see /proc/cpuinfo flags, so on frequency change, this ought to happen. The kernel will automatically switch to something else.

To fix it you could try adding acpi=off to the end of the kernel boot in grub.conf

Expert Comment

ID: 24328556
For Ubuntu users, the file you need to edit is /boot/grub/menu.lst

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