《操作系统》的实验代码。
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80 lines
1.9 KiB

#include <ulib.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define TOTAL 5
/* to get enough accuracy, MAX_TIME (the running time of each process) should >1000 mseconds. */
#define MAX_TIME 1000
#define SLEEP_TIME 400
unsigned int acc[TOTAL];
int status[TOTAL];
int pids[TOTAL];
static void
spin_delay(void)
{
int i;
volatile int j;
for (i = 0; i != 200; ++ i)
{
j = !j;
}
}
int
main(void) {
int i,time;
cprintf("priority process will sleep %d ticks\n",SLEEP_TIME);
sleep(SLEEP_TIME);
memset(pids, 0, sizeof(pids));
lab6_set_priority(TOTAL + 1);
for (i = 0; i < TOTAL; i ++) {
acc[i]=0;
if ((pids[i] = fork()) == 0) {
lab6_set_priority(i + 1);
acc[i] = 0;
while (1) {
spin_delay();
++ acc[i];
if(acc[i]%4000==0) {
if((time=gettime_msec())>MAX_TIME+SLEEP_TIME) {
cprintf("child pid %d, acc %d, time %d\n",getpid(),acc[i],time);
exit(acc[i]);
}
}
}
}
if (pids[i] < 0) {
goto failed;
}
}
cprintf("main: fork ok,now need to wait pids.\n");
for (i = 0; i < TOTAL; i ++) {
status[i]=0;
waitpid(pids[i],&status[i]);
cprintf("main: pid %d, acc %d, time %d\n",pids[i],status[i],gettime_msec());
}
cprintf("main: wait pids over\n");
cprintf("stride sched correct result:");
for (i = 0; i < TOTAL; i ++)
{
cprintf(" %d", (status[i] * 2 / status[0] + 1) / 2);
}
cprintf("\n");
return 0;
failed:
for (i = 0; i < TOTAL; i ++) {
if (pids[i] > 0) {
kill(pids[i]);
}
}
panic("FAIL: T.T\n");
}