1 2 #include <sys/time.h> 3 /* int gettimeofday(struct timeval *tp, struct timezone *tzp); */ 4 5 double second() 6 { 7 /* struct timeval { long tv_sec; 8 long tv_usec; }; 9 10 struct timezone { int tz_minuteswest; 11 int tz_dsttime; }; */ 12 13 struct timeval tp; 14 struct timezone tzp; 15 int i; 16 17 i = gettimeofday(&tp,&tzp); 18 return ((double) tp.tv_sec + (double) tp.tv_usec * 1.e-6); 19 } 20 # include <stdio.h> 21 # include <math.h> 22 # include <limits.h> 23 # include <float.h> 24 # include <sys/time.h> 25 26 /* 27 * Program: Stream 28 * Programmer: Joe R. Zagar 29 * Revision: 4.0-BETA, October 24, 1995 30 * Original code developed by John D. McCalpin 31 * 32 * This program measures memory transfer rates in MB/s for simple 33 * computational kernels coded in C. These numbers reveal the quality 34 * of code generation for simple uncacheable kernels as well as showing 35 * the cost of floating-point operations relative to memory accesses. 36 * 37 * INSTRUCTIONS: 38 * 39 * 1) Stream requires a good bit of memory to run. Adjust the 40 * value of 'N' (below) to give a 'timing calibration' of 41 * at least 20 clock-ticks. This will provide rate estimates 42 * that should be good to about 5% precision. 43 */ 44 45 # define N 200000 46 # define NTIMES 50 47 # define OFFSET 0 48 49 /* 50 * 3) Compile the code with full optimization. Many compilers 51 * generate unreasonably bad code before the optimizer tightens 52 * things up. If the results are unreasonably good, on the 53 * other hand, the optimizer might be too smart for me! 54 * 55 * Try compiling with: 56 * cc -O stream_d.c second.c -o stream_d -lm 57 * 58 * This is known to work on Cray, SGI, IBM, and Sun machines. 59 * 60 * 61 * 4) Mail the results to mccalpin@cs.virginia.edu 62 * Be sure to include: 63 * a) computer hardware model number and software revision 64 * b) the compiler flags 65 * c) all of the output from the test case. 66 * Thanks! 67 * 68 */ 69 70 # define HLINE "-------------------------------------------------------------\n" 71 72 # ifndef MIN 73 # define MIN(x,y) ((x)<(y) ? (x) : (y)) 74 # endif 75 # ifndef MAX 76 # define MAX(x,y) ((x)>(y) ? (x) : (y)) 77 # endif 78 79 static double a[N+OFFSET], 80 b[N+OFFSET], 81 c[N+OFFSET]; 82 /*double *a,*b,*c;*/ 83 84 static double mintime[4] = {FLT_MAX,FLT_MAX,FLT_MAX,FLT_MAX}; 85 86 static const char *label[4] = {"Copy: ", "Scale: ", "Add: ", "Triad: "}; 87 88 static double bytes[4] = { 89 2 * sizeof(double) * N, 90 2 * sizeof(double) * N, 91 3 * sizeof(double) * N, 92 3 * sizeof(double) * N 93 }; 94 95 extern double second(); 96 97 int main(int argc,char **args) 98 { 99 int checktick(void); 100 register int j, k; 101 double scalar, t, times[4][NTIMES],irate[4]; 102 103 /* --- SETUP --- determine precision and check timing --- */ 104 105 for (j=0; j<N; j++) { 106 a[j] = 1.0; 107 b[j] = 2.0; 108 c[j] = 0.0; 109 } 110 111 t = second(); 112 for (j = 0; j < N; j++) a[j] = 2.0E0 * a[j]; 113 t = 1.0E6 * (second() - t); 114 115 /* --- MAIN LOOP --- repeat test cases NTIMES times --- */ 116 117 scalar = 3.0; 118 for (k=0; k<NTIMES; k++) 119 { 120 121 times[0][k] = second(); 122 /* should all these barriers be pulled outside of the time call? */ 123 124 for (j=0; j<N; j++) c[j] = a[j]; 125 times[0][k] = second() - times[0][k]; 126 127 times[1][k] = second(); 128 129 for (j=0; j<N; j++) b[j] = scalar*c[j]; 130 times[1][k] = second() - times[1][k]; 131 132 times[2][k] = second(); 133 for (j=0; j<N; j++) c[j] = a[j]+b[j]; 134 times[2][k] = second() - times[2][k]; 135 136 times[3][k] = second(); 137 for (j=0; j<N; j++) a[j] = b[j]+scalar*c[j]; 138 times[3][k] = second() - times[3][k]; 139 } 140 141 /* --- SUMMARY --- */ 142 143 for (k=0; k<NTIMES; k++) 144 for (j=0; j<4; j++) mintime[j] = MIN(mintime[j], times[j][k]); 145 146 for (j=0; j<4; j++) irate[j] = 1.0E-06 * bytes[j]/mintime[j]; 147 148 printf("Function Rate (MB/s) \n"); 149 for (j=0; j<4; j++) printf("%s%11.4f\n", label[j],irate[j]); 150 return 0; 151 } 152 153 # define M 20 154 155 int checktick(void) 156 { 157 int i, minDelta, Delta; 158 double t1, t2, timesfound[M]; 159 160 /* Collect a sequence of M unique time values from the system. */ 161 162 for (i = 0; i < M; i++) { 163 t1 = second(); 164 while (((t2=second()) - t1) < 1.0E-6) ; 165 timesfound[i] = t1 = t2; 166 } 167 168 /* 169 * Determine the minimum difference between these M values. 170 * This result will be our estimate (in microseconds) for the 171 * clock granularity. 172 */ 173 174 minDelta = 1000000; 175 for (i = 1; i < M; i++) { 176 Delta = (int)(1.0E6 * (timesfound[i]-timesfound[i-1])); 177 minDelta = MIN(minDelta, MAX(Delta,0)); 178 } 179 180 return(minDelta); 181 } 182 183