a sysctl machdep.tsc_freq problem

Uwe Doering gemini at geminix.org
Sat Feb 21 15:29:27 PST 2004

ouyang kai wrote:
>   i found a strange case, i have tested the three machines(PIII 800 & 
> FreeBSD4.9-stable,
> P4-1.6G & FreeBSD4.8-release, P4-2.0G & FreeBSD5.2.1).
>   I use "sysctl -a | grep machdep.tsc.freq" to get the CUP speed. But, I 
> failed on the P4-1.6G machine. Nothing appears.
>  Should I set some additional stuff on the P4-1.6G machine? I have do 
> nothing specailly for the other two machines, but it works.

Is the P4-1.6G machine a multi-processor system, that is, was the kernel 
compiled with the SMP option?  If so, there is currently no TSC support 
on multi-processor systems, for technical reasons I understand.  So in 
this case 'machdep.tsc.freq' is omitted from the kernel and therefore 
cannot be queried.

Uwe Doering         |  EscapeBox - Managed On-Demand UNIX Servers
gemini at geminix.org  |  http://www.escapebox.net

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