Posix Pthread互斥

Question

我已經在代碼的注釋中寫了我的問題。

我試圖通過使用pthreads使我的代碼並行。 首先，我想通過多個線程並行地將大量數據寫入內存。 寫入數據后，我想通過相同的線程執行此數據。 在執行數據之后，我想讀取它。 經過這三個操作之后，我想將此數據傳遞到其他文件。 我想重復此過程幾次。

非常感謝您的幫助。 謝謝。

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

#define ARRAYSIZE 100
#define NUMTHREADS 7

struct ThreadData {
    int start, stop, id;
    int* array;
};

/* function to write, execute and read data */
void* cal(void* td) {
    struct ThreadData* data=(struct ThreadData*) td;
    int start=data->start;
    int stop=data->stop;
    int thread_id = data ->id;
    int i,s, counter;
    counter = 0;

    //main loop
    for (s=0; s<200; s++){

        // in this loop1, I want to write data here by all the threads
        for (i=start; i<stop; i++) {
    printf("thread %d is writing data\n", thread_id);
        }

        //in this loop2, after data written by all the threads in loop1,
        // data is execuated by all threads in this loop2 
        for (i=start; i<stop; i++) {
    printf("thread %d is executing data\n", thread_id);
        }

        //in this loop3, data is read after completion of 
        // writing and execution in loop1 and loop2
        for (i=start; i<stop; i++) {
    printf("thread %d is reading data\n", thread_id);
        }

        // counter, I want this counter to be executed only once 
        // per iteration after writing, executing and reading data.
        counter = counter +1;
    printf ("Value of counter is %d\n", counter); 

    }

    return NULL;
}

int main(void) {
    int array[ARRAYSIZE];
    pthread_t thread[NUMTHREADS];
    struct ThreadData data[NUMTHREADS];
    int i;

    int tasksPerThread=(ARRAYSIZE+NUMTHREADS-1)/NUMTHREADS;

    /* Divide work for threads, prepare parameters */
    for (i=0; i<NUMTHREADS; i++) {
        data[i].start=i*tasksPerThread;
        data[i].stop=(i+1)*tasksPerThread;
        data[i].array=array;
        data[i].id = i;
    }
    /* the last thread must not go past the end of the array */
    data[NUMTHREADS-1].stop=ARRAYSIZE;

    /* Launch Threads */
    for (i=0; i<NUMTHREADS; i++) {
        pthread_create(&thread[i], NULL, cal, &data[i]);
    }

    /* Wait for Threads to Finish */
    for (i=0; i<NUMTHREADS; i++) {
        pthread_join(thread[i], NULL);
    }

    return 0;
}

Answer 1

我認為您僅需要針對計數器的互斥，因此在它之前執行線程同步步驟就足夠了。