MIT6.828 Fall2018 筆記 - Homework 6: Threads and Locking

Homework: Threads and Locking

定義聲明全局變量lock

pthread_mutex_t lock;

在main函數中初始化該互斥鎖

int main(int argc, char* argv[]) {
    pthread_mutex_init(&lock, NULL);
    // ... 省略

insert會修改臨界區的內容，因此須要修改put函數：

static void put(int key, int value) {
    int i = key % NBUCKET;
    pthread_mutex_lock(&lock);
    insert(key, value, &table[i], table[i]);
    pthread_mutex_unlock(&lock);
}

結果：

❯ clang -g -O2 ph.c -pthread
❯ ./a.out 2
1: put time = 0.021635
0: put time = 0.021972
1: get time = 8.328023
1: 0 keys missing
0: get time = 8.329496
0: 0 keys missing
completion time = 8.351818