freebsd - Using system calls from C, how do I get the utilization of the CPU(s)? -

In free BSD in C, how does a CPU use use?

I am writing some code to handle HTTP redirection if CPU load goes beyond the limit on a FReeBSD system, then I want to redirect client requests. Searching on the man page, kvm_getpcpu () seems correct, but do not document man page (which I have read).

Any suggestions or hints have been given - Thanks!

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After reading the answer here, I was able to come down with due to poor documentation, I agree 100% not sure that this is correct, but the top agree. Thanks for all the people.

  #include & lt; Stdio.h & gt; #include & lt; String.h & gt; # Include & lt; Sys / types.h & gt; # Include & lt; Sys / sysctl.h & gt; # Include & lt; Unistd.h & gt; #define CP_USER 0 #define CP_NICE 1 #define CP_SYS 2 #define CP_INTR 3 #define CP_IDLE Define 4 # 5 Int main () {long [Kmbuddhi] last [Seepitiattia]; Size_t cur_sz = Size size; Int State, I; Long amount; Double use; Memeset (last, 0, last of size); For (i = 0; i & lt; 6; i ++) {if (sysctlbyname ( "kern.cp_time", & amp; cur, & amp; cur_sz, NULL, 0) & lt; 0) {printf ( "kern.cp_times reading sysctl error" n "); return -1;} Sum = 0; (state = 0; state & lt; Seepitiattis; state ++) {long TMP = CR [state]; Q [ State] - last [state]; last [state] = tmp; sum + = cur [state];} Util = 100.0L - (100.0L * cur [CP_IDLE] / (yoga (double) sum: 1.0 L)) ; Printf ("CPU usage:% 7.3f \ n", use); Sleep (1);} Return 0;} << / P> 
  NAME    
 
 
 / Lt>  
   Lkvm)  
 < Strong> SYNOPSIS   
  #include & Lt; sys / param.h & gt; # Include & lt; sys / pcpu.h & gt; # Include & lt; sys / sysctl.h & gt; # Include & lt; kvm.h & gt; Int kvm_getmaxcpu (kvm_t * kd); void * kvm_getpcpu (kvm_t * kd, int cpu);   
  description   
 kvm_getmaxcpu () and kvm_getpcpu () function to per-CPU data reported by used to reach the per-CPU data of active processor kernel supported by Kvm_getmaxcpu () function in the kernel gives the maximum number of CPU to a CPU Kvm_getpcpu () function Give buffer Is obtained. This buffer is described by the protected pcpu type. Caller is responsible for releasing buffer through a call for free (3) when it is not needed if the CPU is not active, then instead of returning to the tap.  
  Caching   
 These functions cache the nlist values ​​for different kernel variables that are reuse in consecutive calls.  
  returns Valian   
 On success, kvm_getmaxcpu () function returns the maximum number an error occurs if supported by the kernel CPU, so instead of 1 Returns.  
 On success, the kvm_getpcpu () function returns a pointer to the allocated buffer or tap. If an error occurs, then it returns in return for 1.  
 If a function encounters an error, an error message can be obtained by kvm_geterr (3.)  
 
  Edit   
 Here is the kvm_t struct:  
  struct __kvm {/ * * The string to be added in the error message * provided for compatibility with the interface of the sun * If this value is empty, then error is saved in the errbuf [] * / const char * program; Four * errp; / * XXX This might go away * / Four fault [_POSIX2_LINE_MAX]; # Defined isylive (kd) (kd) -> gt; vmfd = 0) int pmfd; / * Physical memory file (or crashdump) * / int vmfd; / * Virtual Memory File (-1 if crashdump) * / int unused; / * Was: swap file (e.g., / dev / drum) * / int nlfd; / * Name file (e.g., / kernel) * / struct kinfo_proc * procbase; Char * argspc; / * (Dynamic) storage for argv string * / int arglen; / * Above * / four ** argv; Length of; / * (Dynamic) storage for argent pointers * / int argc; / * Above length (actual # is not present) * / Four * Arguf; / * (Dynamic) temporary storage * / / * * kernel virtual address translation status. It only fills up for the dying kernel; Otherwise, the running kernel (i.e. kimam) * will translate for us. This can be big, so we * allocate it if necessary. * / Struct vmstate * vmst; };