Linux-强制单核执行和使用pthread调试多线程

我正在用C、pthread和Linux调试多线程问题。在我的MacOS 10.5.8上,c2d运行良好,在我的Linux计算机上(2-4核),它产生不需要的输出。

我没有经验,所以我附上了我的代码。这相当简单:每个新线程都会再创建两个线程,直到达到最大值。所以没什么大不了的…就像我几天前想的那样。

valgrind --tool=drd --read-var-info=yes --trace-mutex=no ./threads

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define MAX_THR      12
#define NEW_THR      2

int wait_time = 0;  // log global wait time
int num_threads = 0;    // how many threads there are
pthread_t threads[MAX_THR]; // global array to collect threads
pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER; // sync

struct thread_data 
{
    int nr;             // nr of thread, serves as id
    int time;           // wait time from rand()
};
struct thread_data thread_data_array[MAX_THR+1];


void 
*PrintHello(void *threadarg)
{

  if(num_threads < MAX_THR){
    // using the argument

    pthread_mutex_lock(&mut);
    struct thread_data *my_data;
    my_data = (struct thread_data *) threadarg;

    // updates
    my_data->nr = num_threads;
    my_data->time= rand() % 10 + 1;

    printf("Hello World! It's me, thread #%d and sleep time is %d!\n", 
                my_data->nr, 
                my_data->time); 

     pthread_mutex_unlock(&mut);

   // counter
   long t = 0;

   for(t = 0; t < NEW_THR; t++){
        pthread_mutex_lock(&mut);
            num_threads++;
            wait_time += my_data->time;
           pthread_mutex_unlock(&mut);
        pthread_create(&threads[num_threads], NULL, PrintHello, &thread_data_array[num_threads]);
      sleep(1);
   }
    printf("Bye from %d thread\n", my_data->nr);

   pthread_exit(NULL);
   }
   return 0;
}

int 
main (int argc, char *argv[])
{

    long t = 0;
    // srand(time(NULL));
    if(num_threads < MAX_THR){
       for(t = 0; t < NEW_THR; t++){
          // -> 2 threads entry point
          pthread_mutex_lock(&mut);
                 // rand time
                 thread_data_array[num_threads].time  = rand() % 10 + 1;
           // update global wait time variable
              wait_time += thread_data_array[num_threads].time;
              num_threads++;
        pthread_mutex_unlock(&mut);
        pthread_create(&threads[num_threads], NULL, PrintHello, &thread_data_array[num_threads]);
         pthread_mutex_lock(&mut);
        printf("In main: creating initial thread #%ld\n", t);
        pthread_mutex_unlock(&mut);

      }
    }

   for(t = 0; t < MAX_THR; t++){
        pthread_join(threads[t], NULL);
    }

    printf("Bye from program, wait was %d\n", wait_time);
    pthread_exit(NULL);
}

printf("Bye from %d thread\n", my_data->nr);

In main: creating initial thread #0
Hello World! It's me, thread #2 and sleep time is 8!
In main: creating initial thread #1
[...]
Hello World! It's me, thread #11 and sleep time is 8!
Bye from 9 thread
Bye from 5 thread
Bye from -1376900240 thread
[...]