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Re: rdtscp instruction

On 25.07.2010 00:31, Christoph Egger wrote:
> The differences between RDTSC and RDTSCP are:
> - RDTSCP is a serializing instruction
> - RDTSCP additionally loads the lower 32bits
>   of MSR_TSC_AUX into ecx register.
> The MSR_TSC_AUX (0xc0000103) is read-write
> for the OS and can be filled with anything
> meaningful to the OS (i.e. processor ID).
> The upper 32bits are reserved.
> The MSR exists for each CPU-core.
> The question is: What useful information
> can NetBSD store into MSR_TSC_AUX ?

What do other kernels store in this MSR?

Jean-Yves Migeon

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