check_sync.c
#include <stdio.h>
#include <proc.h>
#include <sem.h>
#include <monitor.h>
#include <assert.h>
#define N 5 /* 哲学家数目 */
#define LEFT (i-1+N)%N /* i的左邻号码 */
#define RIGHT (i+1)%N /* i的右邻号码 */
#define THINKING 0 /* 哲学家正在思考 */
#define HUNGRY 1 /* 哲学家想取得叉子 */
#define EATING 2 /* 哲学家正在吃面 */
#define TIMES 4 /* 吃4次饭 */
#define SLEEP_TIME 10
//-----------------philosopher problem using monitor ------------
/*PSEUDO CODE :philosopher problem using semaphore
system DINING_PHILOSOPHERS
VAR
me: semaphore, initially 1; # for mutual exclusion
s[5]: semaphore s[5], initially 0; # for synchronization
pflag[5]: {THINK, HUNGRY, EAT}, initially THINK; # philosopher flag
# As before, each philosopher is an endless cycle of thinking and eating.
procedure philosopher(i)
{
while TRUE do
{
THINKING;
take_chopsticks(i);
EATING;
drop_chopsticks(i);
}
}
# The take_chopsticks procedure involves checking the status of neighboring
# philosophers and then declaring one's own intention to eat. This is a two-phase
# protocol; first declaring the status HUNGRY, then going on to EAT.
procedure take_chopsticks(i)
{
DOWN(me); # critical section
pflag[i] := HUNGRY;
test[i];
UP(me); # end critical section
DOWN(s[i]) # Eat if enabled
}
void test(i) # Let phil[i] eat, if waiting
{
if ( pflag[i] == HUNGRY
&& pflag[i-1] != EAT
&& pflag[i+1] != EAT)
then
{
pflag[i] := EAT;
UP(s[i])
}
}
# Once a philosopher finishes eating, all that remains is to relinquish the
# resources---its two chopsticks---and thereby release waiting neighbors.
void drop_chopsticks(int i)
{
DOWN(me); # critical section
test(i-1); # Let phil. on left eat if possible
test(i+1); # Let phil. on rght eat if possible
UP(me); # up critical section
}
*/
//---------- philosophers problem using semaphore ----------------------
int state_sema[N]; /* 记录每个人状态的数组 */
/* 信号量是一个特殊的整型变量 */
semaphore_t mutex; /* 临界区互斥 */
semaphore_t s[N]; /* 每个哲学家一个信号量 */
struct proc_struct *philosopher_proc_sema[N];
void phi_test_sema(i) /* i：哲学家号码从0到N-1 */
{
if(state_sema[i]==HUNGRY&&state_sema[LEFT]!=EATING
&&state_sema[RIGHT]!=EATING)
{
state_sema[i]=EATING;
up(&s[i]);
}
}
void phi_take_forks_sema(int i) /* i：哲学家号码从0到N-1 */
{
down(&mutex); /* 进入临界区 */
state_sema[i]=HUNGRY; /* 记录下哲学家i饥饿的事实 */
phi_test_sema(i); /* 试图得到两只叉子 */
up(&mutex); /* 离开临界区 */
down(&s[i]); /* 如果得不到叉子就阻塞 */
}
void phi_put_forks_sema(int i) /* i：哲学家号码从0到N-1 */
{
down(&mutex); /* 进入临界区 */
state_sema[i]=THINKING; /* 哲学家进餐结束 */
phi_test_sema(LEFT); /* 看一下左邻居现在是否能进餐 */
phi_test_sema(RIGHT); /* 看一下右邻居现在是否能进餐 */
up(&mutex); /* 离开临界区 */
}
int philosopher_using_semaphore(void * arg) /* i：哲学家号码，从0到N-1 */
{
int i, iter=0;
i=(int)arg;
cprintf("I am No.%d philosopher_sema\n",i);
while(iter++<TIMES)
{ /* 无限循环 */
cprintf("Iter %d, No.%d philosopher_sema is thinking\n",iter,i); /* 哲学家正在思考 */
do_sleep(SLEEP_TIME);
phi_take_forks_sema(i);
/* 需要两只叉子，或者阻塞 */
cprintf("Iter %d, No.%d philosopher_sema is eating\n",iter,i); /* 进餐 */
do_sleep(SLEEP_TIME);
phi_put_forks_sema(i);
/* 把两把叉子同时放回桌子 */
}
cprintf("No.%d philosopher_sema quit\n",i);
return 0;
}
//-----------------philosopher problem using monitor ------------
/*PSEUDO CODE :philosopher problem using monitor
* monitor dp
* {
* enum {thinking, hungry, eating} state[5];
* condition self[5];
*
* void pickup(int i) {
* state[i] = hungry;
* if ((state[(i+4)%5] != eating) && (state[(i+1)%5] != eating)) {
* state[i] = eating;
* else
* self[i].wait();
* }
*
* void putdown(int i) {
* state[i] = thinking;
* if ((state[(i+4)%5] == hungry) && (state[(i+3)%5] != eating)) {
* state[(i+4)%5] = eating;
* self[(i+4)%5].signal();
* }
* if ((state[(i+1)%5] == hungry) && (state[(i+2)%5] != eating)) {
* state[(i+1)%5] = eating;
* self[(i+1)%5].signal();
* }
* }
*
* void init() {
* for (int i = 0; i < 5; i++)
* state[i] = thinking;
* }
* }
*/
struct proc_struct *philosopher_proc_condvar[N]; // N philosopher
int state_condvar[N]; // the philosopher's state: EATING, HUNGARY, THINKING
monitor_t mt, *mtp=&mt; // monitor
void phi_test_condvar (i) {
if(state_condvar[i]==HUNGRY&&state_condvar[LEFT]!=EATING
&&state_condvar[RIGHT]!=EATING) {
cprintf("phi_test_condvar: state_condvar[%d] will eating\n",i);
state_condvar[i] = EATING ;
cprintf("phi_test_condvar: signal self_cv[%d] \n",i);
cond_signal(&mtp->cv[i]) ;
}
}
void phi_take_forks_condvar(int i) {
down(&(mtp->mutex));
//--------into routine in monitor--------------
// LAB7 EXERCISE1: YOUR CODE
// I am hungry
// try to get fork
// I am hungry
state_condvar[i]=HUNGRY;
// try to get fork
phi_test_condvar(i);
if (state_condvar[i] != EATING) {
cprintf("phi_take_forks_condvar: %d didn't get fork and will wait\n",i);
cond_wait(&mtp->cv[i]);
}
//--------leave routine in monitor--------------
if(mtp->next_count>0)
up(&(mtp->next));
else
up(&(mtp->mutex));
}
void phi_put_forks_condvar(int i) {
down(&(mtp->mutex));
//--------into routine in monitor--------------
// LAB7 EXERCISE1: YOUR CODE
// I ate over
// test left and right neighbors
// I ate over
state_condvar[i]=THINKING;
// test left and right neighbors
phi_test_condvar(LEFT);
phi_test_condvar(RIGHT);
//--------leave routine in monitor--------------
if(mtp->next_count>0)
up(&(mtp->next));
else
up(&(mtp->mutex));
}
//---------- philosophers using monitor (condition variable) ----------------------
int philosopher_using_condvar(void * arg) { /* arg is the No. of philosopher 0~N-1*/
int i, iter=0;
i=(int)arg;
cprintf("I am No.%d philosopher_condvar\n",i);
while(iter++<TIMES)
{ /* iterate*/
cprintf("Iter %d, No.%d philosopher_condvar is thinking\n",iter,i); /* thinking*/
do_sleep(SLEEP_TIME);
phi_take_forks_condvar(i);
/* need two forks, maybe blocked */
cprintf("Iter %d, No.%d philosopher_condvar is eating\n",iter,i); /* eating*/
do_sleep(SLEEP_TIME);
phi_put_forks_condvar(i);
/* return two forks back*/
}
cprintf("No.%d philosopher_condvar quit\n",i);
return 0;
}
void check_sync(void){
int i;
//check semaphore
sem_init(&mutex, 1);
for(i=0;i<N;i++){
sem_init(&s[i], 0);
int pid = kernel_thread(philosopher_using_semaphore, (void *)i, 0);
if (pid <= 0) {
panic("create No.%d philosopher_using_semaphore failed.\n");
}
philosopher_proc_sema[i] = find_proc(pid);
set_proc_name(philosopher_proc_sema[i], "philosopher_sema_proc");
}
//check condition variable
monitor_init(&mt, N);
for(i=0;i<N;i++){
state_condvar[i]=THINKING;
int pid = kernel_thread(philosopher_using_condvar, (void *)i, 0);
if (pid <= 0) {
panic("create No.%d philosopher_using_condvar failed.\n");
}
philosopher_proc_condvar[i] = find_proc(pid);
set_proc_name(philosopher_proc_condvar[i], "philosopher_condvar_proc");
}
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