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Date: Sat, 21 May 2005 16:03:08 +0300 (EEST)
From: Giorgos Keramidas <keramida@ceid.upatras.gr>
To: shiner chen <shiner_chen@yahoo.com.cn>
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X-Mailman-Approved-At: Sun, 22 May 2005 12:04:08 +0000
Cc: freebsd-hackers@freebsd.org
Subject: Re: how to get the status of cpu in kernel?
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On 2005-05-21 18:49, shiner chen wrote:
> In order to implement a dispacthing policy I want to get the status of 
> cpu. I have read the code of top command and i find it get the status 
> of cpu by the function :
>
>    int sysctlbyname(const char *, void *, size_t *, void *, size_t);
>
> I search the code of kernel ,then I consider that i can get the status 
> of cpu through the funciton:
>
>     int kernel_sysctlbyname(struct thread *td, char *name,  void *old, 
>         size_t *oldlenp, void *new, size_t newlen,  size_t *retval);
>
> I try to get the status of cpu by that function ,but it does not work!

You're looking at the wrong place.  There is a manpage for the 
sysctlbyname() function, which you obviously missed.

> who can tell me the problem?

Nobody until you show us the source, I guess :-)

> How do i get the status of cpu?
> How do i use it if the funcion is right? what's the mean of the 
> function's arguments ?

Start by reading the manpage of sysctlbyname().  Then, if you still have 
problems, you can post the source online somewhere and point us people 
at the URL.