Understanding CPU Utilization in VxWorks

Code is provided for learning reference. Please read the comments in the code carefully.

Code is provided for learning reference. Please read the comments in the code carefully.

#include "vxWorks.h"
#include "spyLib.h"
#include "stdio.h"
#include "ioLib.h"
#include "stdarg.h"
#include "taskLib.h" 
#include "sysLib.h" 
#include "string.h"
 
#define SPYTASKSMAX 100 
 
int data_ana(const char*,...); 
 
/* Function: Detect CPU usage and call data_ana function for processing, finally print the usage on shell, can also redirect to print in other locations, main function can call this function directly
 * Input parameters:
 * Return value: 0 
 */ 
int CPU_utilization(void) 
{ 
    spyLibInit(SPYTASKSMAX);//Initialize spy, maximum number of tasks to spy is SPYTASKSMAX 
    spyCommon(5,100,(FUNCPTR)data_ana);//This routine collects task activity data and periodically runs spyReport(). Data is collected several times per second, and a report is generated every few seconds. If freq is zero, it defaults to 5 seconds. If ticksPerSec is omitted or zero, it defaults to 100s 
    return 0; 
} 
 
/* Function: Can send udp messages to different ip addresses
 * Input parameters: const char* fmtPtn,... This parameter is variable length, all parameter types are const char*, assigned to rbuf in a loop through v1, thus obtaining each line output by the spy function on shell, and after processing the line content, the CPU usage is obtained
 * Return value: 0 
 */ 
int data_ana(const char* fmtPtn,...) 
{ 
    char rbuf[256]; 
    const char* IDEL = "IDLE"; 
    char percent[50]; 
    int i=0; 
    int j=0; 
    int p; 
    va_list vl; 
    va_start(vl,fmtPtn); 
    vsprintf(rbuf,fmtPtn,vl); //Write v1 to string buf according to format fmtptn, obtaining a line of string.
 
    if(strstr(rbuf,IDEL)!= NULL) 
        /* 
         The IDLE rate indicates the CPU idle proportion, in the spy output information, there is a line for the idel value, after obtaining this value, subtract it from 100 to get the CPU usage
     */ 
    { 
        printf("%s\n",rbuf); 
 
        for(i=0;(i<256)&&(rbuf[i] != '%');i++) 
        { 
         
            if(rbuf[i]>='0'&&rbuf[i]<='9') 
                { 
                    percent[j] = rbuf[i]; 
                    j++; 
                } 
        } 
        percent[j]='\0'; 
        //printf("CPU free percent= %s \n",percent); 
        p=atoi(percent); 
        printf("CPU use percent= %i%%\n",100-p); 
    } 
    va_end(vl); 
    return 0; 
} 

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