Re: [RFC PATCH] tsc: synchronize TSCs on buggy Intel Xeon E5 CPUs with offset error

From: Peter Zijlstra
Date: Fri Nov 13 2015 - 15:44:06 EST


On Wed, Nov 11, 2015 at 09:41:25AM -0600, Gratian Crisan wrote:
> I also wrote a small C utility[1], with a bit of code borrowed from the
> kernel, for reading the TSC on all CPUs. It starts a high priority
> thread per CPU, tries to synchronize them and prints out the TSC values
> and their offset with regards to CPU0.
> It can be called from a SysV init shell script[2] at the beginning of
> the boot process and right before a reboot to save the values in a file.

Could you also read and print TSC_ADJUST (msr 0x3b) ? This would tell us
if for example your BIOS messed it up.

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