cpubound.c

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>

double CPUWork(double a1,double b1,double c1)
{
 double a = 30.0*a1, b = 40.0*b1, c =50.0*c1, d=0; 
 double norm = sqrt(a*a + b*b + c*c);
 double sum = sqrt((a/norm)*(a/norm) + (b/norm)*(b/norm) + (c/norm)*(c/norm));
 return sum;
}

#define SEC_PER_MIN 60
#define SEC_PER_HOUR (SEC_PER_MIN*60)

int GetCurrentSecondOfDay()
{
	//https://stackoverflow.com/questions/2242963/get-the-current-time-in-seconds
	time_t now;
	struct tm *tm;
	now = time(0);
	if((tm = localtime(&now)) == NULL)
	{
		fprintf(stderr,"Error extracting time stuff\n");
		exit(-1);
	}
	int hour_seconds = tm->tm_hour*SEC_PER_HOUR;
	int min_seconds = tm->tm_min*SEC_PER_MIN;
	int seconds = tm->tm_sec;
	return hour_seconds + min_seconds + seconds;
}

int HasXSecondsPassed(int X, int start, int end)
{
	int span = end - start;
	if( span > X)
	{
		return 1;
	}
	return 0;
}

void PrintUsage(int argc, char**argv)
{
	fprintf(stderr,"\nInvalid command line entered: \n");
	int i = 0;
	for(i =0; i<argc; i++)
	{
		fprintf(stdout,"Argument %d is: \"%s\"\n",i,argv[i]);
	}

	fprintf(stderr,"\ncpubound has 2 modes, both requires 2 arguments:\n");
	fprintf(stderr,"Mode 1: Calculate avg cycles per X minute.\n");
	fprintf(stderr,"cpubound -minutes X\n");
	fprintf(stderr,"Mode 2: N is avg cycles per minute. X is the number of minutes to run.\n");
	fprintf(stderr,"cpubound -cycles N -minutes X\n\n");

	exit(-1);
}

long long DoWorkCycles()
{
	int i=0;
	int LoopCount = 100000;
	long long cycles = 0;
	for(i=0; i<LoopCount; i++)
	{
		double scale = 0.0;
		while(-1 < scale && scale < 1)	// don't scale all of a triangles sides by 0.0/small numbers.
		{
			scale = (double)rand();
		}
		double result = CPUWork(scale,scale,scale); 
		if(0.9 < result && result < 1.1)
		{
			
				}
		else
		{
			fprintf(stderr,"Bad Result from CPU Work Computation, should be 1.0: %f, scale is: %f\n",result,scale);
		}

	}
	cycles =1;

	return cycles;
}

void PrintCycles(int start,int end, long long cycles)
{
	int span = end-start;
	int seconds = span%60;
	int minutes = span/60;

	fprintf(stdout,"Total Minutes:Seconds = %d:%d\n",minutes,seconds);
	fprintf(stdout,"Total Cycles: %lld\n",cycles);
	
	double avg_cyc_per_sec = ((double)cycles)/((double)span);
	fprintf(stdout,"Avg Cycles Per Sec: %f\n",avg_cyc_per_sec);

	double avg_cyc_per_min = ((double)cycles)/((double)minutes);
	fprintf(stdout,"Avg Cycles Per Min: %f\n",avg_cyc_per_min);
}

void DoCyclesPerMinutesCalc(int minutes)
{
	int start = GetCurrentSecondOfDay();
	int end = GetCurrentSecondOfDay();
	int lastend = end;
	long long cycles = 0;
	int done = 0;
	do
	{
		//printf("Cycle %lld in CyclesPerMinutesCalc %d\n",cycles,minutes);
		cycles += DoWorkCycles();
		end = GetCurrentSecondOfDay();
		if(HasXSecondsPassed(minutes*SEC_PER_MIN,start,end)==1)
		{
			done=1;
		}
	//}while(HasXSecondsPassed(minutes*SEC_PER_MIN,start,end)==0);
	}while(done ==0);
	end = GetCurrentSecondOfDay();
	PrintCycles(start,end,cycles);
}

void DoTotalWorkCycles(long long work_cycles)
{
	int start = GetCurrentSecondOfDay();
	int end = GetCurrentSecondOfDay();
	long long cycles = 0;
	fprintf(stdout,"Do CPU Work Cycles: %lld\n",work_cycles);
	while(cycles < work_cycles)	
	{
		//printf("Cycle %lld in DoTotalWorkCycles %lld\n",cycles,work_cycles);
		cycles += DoWorkCycles();
		end = GetCurrentSecondOfDay();
	}
	end = GetCurrentSecondOfDay();	
	PrintCycles(start,end,cycles);
}

int main(int argc, char **argv) {
    long long i;
    long long cycles = 0;
    long long minutes = 0;
    int use_cycles = 0;

/*
 * process environment variable and command line arguments
 */
    if( ! ((argc ==3)||(argc==5)))
    {
	    PrintUsage(argc,argv);
    }   
    for (i = 1; i + 1< argc; i++) {
        if (strcmp(argv[i], "-minutes") == 0) {
            i++;
            minutes = (long long)atoi(argv[i]);
	    
        } else if (strcmp(argv[i], "-cycles") == 0) 
	{
		if(argc!=5)
		{
			PrintUsage(argc,argv);
		}

            i++;
            cycles = strtoll(argv[i],NULL,10);
	    use_cycles =1;
        } else {
            fprintf(stderr, "Illegal flag: `%s'\n", argv[i]);
            PrintUsage(argc,argv);
        }
    }
    if(use_cycles)
    {
	DoTotalWorkCycles(cycles*minutes);
    }
    else
    {
	DoCyclesPerMinutesCalc(minutes);
    }
    return 0;
}