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use rdtscp to determine the calcualtion time

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This commit is contained in:
Stefan Lankes 2015-07-31 22:31:07 +02:00
parent 9b79795304
commit a025cc1c4a
1 changed files with 41 additions and 4 deletions
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45
hermit/newlib/examples/jacobi.c
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@ -39,6 +39,43 @@
#define CACHE_SIZE (256*1024)
#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))
extern unsigned int get_cpufreq();
inline static unsigned long long rdtscp(void)
{
unsigned long long lo, hi;
asm volatile ("rdtscp" : "=a"(lo), "=d"(hi) :: "%rcx");
return (hi << 32 | lo);
}
double mysecond()
{
#if 0
struct timeval tp;
struct timezone tzp;
int i;
i = gettimeofday(&tp,&tzp);
return ( (double) tp.tv_sec + (double) tp.tv_usec * 1.e-6 );
#else
static unsigned long long start;
static int init = 0;
double ret;
if (init) {
ret = (double) (rdtscp() - start) / ((double) get_cpufreq() * 1000000.0);
} else {
//printf("CPU frequency: %d MHz\n", get_cpufreq());
start = rdtscp();
init = 1;
ret = 0.0;
}
return ret;
#endif
}
static int generate_empty_matrix(double*** A , unsigned int N) {
unsigned int iCnt;
int i,j;
@ -107,7 +144,7 @@ int main(int argc, char **argv)
double** A=0;
double* X;
double* X_old, xi;
clock_t start, end;
double start, end;
if (generate_empty_matrix(&A,MATRIX_SIZE) < 0)
{
@ -137,7 +174,7 @@ int main(int argc, char **argv)
iter_start = 0;
iter_end = MATRIX_SIZE;
start = clock();
start = mysecond();
while(1)
{
@ -169,7 +206,7 @@ int main(int argc, char **argv)
}
}
end = clock();
end = mysecond();
if (MATRIX_SIZE < 16) {
printf("Print the solution...\n");
@ -200,7 +237,7 @@ int main(int argc, char **argv)
printf("\nmatrix size: %d x %d\n", MATRIX_SIZE, MATRIX_SIZE);
printf("number of iterations: %d\n", iterations);
printf("calculation time: %f s\n", (float) (end-start) / (float) CLOCKS_PER_SEC);
printf("calculation time: %lf s\n", end-start);
free((void*) X_old);
free((void*) X);