massive clock drift on AMD64 X2 systems

[Joe Bruin]

I have been experiencing huge clock drift (the clock moves up to twice as fast as real time) on my AMD64 Breezy system. I have researched this bug, and strongly believe it to be the same kernel bug reported here:

http://bugzilla.kernel.org/show_bug.cgi?id=5105

There is a solution posted, although I do not know if it was ever integrated into the mainline kernel. The problem stems from improper balancing of the timer interrupt on dual-core AMD64 chips (it is present in both AMD64 and i386 kernels on these systems). The issue manifests itself in particular under heavly loads.

Symptoms:
After an indeterminate amount of time (usually several hours after boot), the system clock will begin to drift faster and faster into the future. Typical clock rates on my machine are about 10% to 30% faster than they should be. I have not noticed this issue until recently, although I cannot recall if this coincided with a kernel upgrade or not. The system is otherwise very stable.

my setup:
linux-image-2.6.12-10-amd64-k8-smp
AMD64 X2 3800+
ASUS A8N5X motherboard
eVGA Geforce 7800GT (using 'nvidia' binary driver)
Ubuntu 5.10 Breezy Badger (AMD64)

I'd be happy to test new kernels/configs.

Thanks,
Joe

[Sebastian Rode (sebastian-ro-deactivatedaccount)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering is this still an issue for you? Can you try with latest Ubuntu release? Thanks in advance.