eed

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
#include <sys/time.h>
#include <sys/resource.h>
#include<unistd.h>
#include<sys/mman.h>
int main(int argc, char** argv){
struct timeval tv;
struct timezone tz;
int i,j,index,iterations,array_size;
float *arrayPtr;
double stop,start,init;
// Lock down all memory for this process
if(mlockall(MCL_CURRENT|MCL_FUTURE)<0){
fprintf(stderr,"Memlock error\n");
exit(1);
}
if (argc!=3) {
fprintf(stderr, "Usage: %s <Size of array><no of iterations>\n", argv[0]);
exit(1);
}
// progname=argv[0];
array_size=atoi(argv[1]);
iterations=atoi(argv[2]);
// Record start
gettimeofday( &tv,&tz);
init=tv.tv_sec + tv.tv_usec*0.000001;
6
// create large float arrays
arrayPtr=calloc(array_size,sizeof(float));
//initialise array
for(i=0;i<array_size;++i) { arrayPtr[i]=9999.99; }
// Main loop
// Process full array and time each pass.. Use random number
// generator to access array randomly .. greater likelihood of paging in unlocked version
for(j=0;j<iterations;++j)
{
gettimeofday( &tv,&tz);
start=tv.tv_sec + tv.tv_usec*0.000001;
// random seed
srand(time(NULL));
for(i=0;i<array_size;++i)
{
// generate random index
index = rand() % array_size;
arrayPtr[index]=arrayPtr[index]/0.9999;
}
gettimeofday( &tv,&tz);
stop=tv.tv_sec + tv.tv_usec*0.000001;
printf("Run time for pass %d is %lf ms\n",j+1, (stop-start)*1000);
// sleep for 10 sec
sleep(10);
// Run multiple versions so unlocked versions may be paged during
// sleep period between passes
}
// release memory
free(arrayPtr);
munlockall(); // unlock memory
gettimeofday( &tv,&tz);
stop=tv.tv_sec + tv.tv_usec*0.000001;
printf("Total Run time is %lf ms\n", (stop-init)*1000);
return 0;
}