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#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <semaphore.h>
#define NUM_THREADS 4
#define COUNT_LIMIT 13
int done = 0;
int count = 0;
int quantum = 2;
int thread_ids[4] = {0,1,2,3};
int thread_runtime[4] = {0,5,4,7};
pthread_mutex_t count_mutex;
pthread_cond_t count_threshold_cv;
void * inc_count(void * arg);
static sem_t count_sem;
int quit = 0;
///////// Inc_Count////////////////
void *inc_count(void *t)
{
long my_id = (long)t;
int i;
sem_wait(&count_sem); /////////////CRIT SECTION//////////////////////////////////
printf("run_thread = %d\n",my_id);
printf("%d \n",thread_runtime[my_id]);
for(i=0; i < thread_runtime[my_id];i++)
{
printf("runtime= %d\n",thread_runtime[my_id]);
pthread_mutex_lock(&count_mutex);
count++;
if (count == COUNT_LIMIT) {
pthread_cond_signal(&count_threshold_cv);
printf("inc_count(): thread %ld, count = %d Threshold reached.\n", my_id,
count);
}
printf("inc_count(): thread %ld, count = %d, unlocking mutex\n",my_id, count);
pthread_mutex_unlock(&count_mutex);
sleep(1) ;
}//End For
sem_post(&count_sem); // Next Thread Enters Crit Section
pthread_exit(NULL);
}
/////////// Count_Watch ////////////////
void *watch_count(void *t)
{
long my_id = (long)t;
printf("Starting watch_count(): thread %ld\n", my_id);
pthread_mutex_lock(&count_mutex);
if (count<COUNT_LIMIT) {
pthread_cond_wait(&count_threshold_cv, &count_mutex);
printf("watch_count(): thread %ld Condition signal received.\n", my_id);
printf("watch_count(): thread %ld count now = %d.\n", my_id, count);
}
pthread_mutex_unlock(&count_mutex);
pthread_exit(NULL);
}
////////////////// Main ////////////////
int main (int argc, char *argv[])
{
int i;
long t1=0, t2=1, t3=2, t4=3;
pthread_t threads[4];
pthread_attr_t attr;
sem_init(&count_sem, 0, 1);
/* Initialize mutex and condition variable objects */
pthread_mutex_init(&count_mutex, NULL);
pthread_cond_init (&count_threshold_cv, NULL);
/* For portability, explicitly create threads in a joinable state */
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
pthread_create(&threads[0], &attr, watch_count, (void *)t1);
pthread_create(&threads[1], &attr, inc_count, (void *)t2);
pthread_create(&threads[2], &attr, inc_count, (void *)t3);
pthread_create(&threads[3], &attr, inc_count, (void *)t4);
/* Wait for all threads to complete */
for (i=0; i<NUM_THREADS; i++) {
pthread_join(threads[i], NULL);
}
printf ("Main(): Waited on %d threads. Done.\n", NUM_THREADS);
/* Clean up and exit */
pthread_attr_destroy(&attr);
pthread_mutex_destroy(&count_mutex);
pthread_cond_destroy(&count_threshold_cv);
pthread_exit(NULL);
}
我想学习线程调度，有很多我不知道的技术编码。我知道在理论上它应该如何工作，但在代码中遇到了麻烦开始......线程调度轮询/调度调度
我知道，至少我认为，这个方案是不是真正的时间和它并不意味着要。 一些如何我需要创建一个调度程序调度来控制它们应该运行的顺序的线程... RR FCFS SJF等
现在我没有调度程序。我所拥有的是控制线程的信号量/互斥量。
此代码并运行FCFS ......我一直在试图使用旗语来创建RR ..但有很多的麻烦。我相信创建一个调度员会更容易，但我不知道如何。
我需要帮助，我不是在寻找答案只是方向..一些示例代码将有助于了解更多。
好的，为了帮助理解，我的第一个想法是使用信号量并尝试创建一个循环，以便当一个线程运行时让我们说2次线程等待其他线程运行两次或直到运行时间结束。
我遇到的问题是，似乎没有这种方式同步线程的好方法。除非有办法为每个线程创建一个独特的信号量。这就是为什么我需要一些帮助或指导来创建调度程序功能。
谢谢。
这就像我的其他帖子，但我尽可能地清理了代码。只是提醒线程0跟踪将被视为我系统时钟的计数器值。 – MRP 2010-04-14 22:12:51