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/* From 4.4 BSD sys/tests/benchmarks/forks.c. */
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <sys/wait.h>
/*
* Benchmark program to calculate fork+wait
* overhead (approximately). Process
* forks and exits while parent waits.
* The time to run this program is used
* in calculating exec overhead.
*/
int
main(argc, argv)
char *argv[];
{
register int nforks, i;
char *cp;
int pid, child, status, brksize;
time_t starttime, endtime;
if (argc < 3) {
printf("usage: %s number-of-forks sbrk-size\n", argv[0]);
exit(1);
}
nforks = atoi(argv[1]);
if (nforks < 0) {
printf("%s: bad number of forks\n", argv[1]);
exit(2);
}
brksize = atoi(argv[2]);
if (brksize < 0) {
printf("%s: bad size to sbrk\n", argv[2]);
exit(3);
}
time (&starttime);
cp = (char *)sbrk(brksize);
if ((int)cp == -1) {
perror("sbrk");
exit(4);
}
for (i = 0; i < brksize; i += 1024)
cp[i] = i;
while (nforks-- > 0) {
child = fork();
if (child == -1) {
perror("fork");
exit(-1);
}
if (child == 0)
_exit(-1);
while ((pid = wait(&status)) != -1 && pid != child)
;
}
time (&endtime);
printf ("Time: %d seconds.\n", (int) (endtime - starttime));
exit(0);
}
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