先给结论：网络瓶颈用线程，cpu瓶颈用进程

运行条件

16核 ubuntu python3+

闲置情况

top-1命令，可以看到16核基本上没负载(us值）

Python单核跑满cpu

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def lp(): 
    while 1: 
        a = 1 
        b = 2 
        c = b + a 
lp()
单核代码，占满了cpu5

三线程Python

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import time 

def add_num(): 
    while 1: 
        a = 1 
        b = 2 
        c = b + a 
 
if __name__ == '__main__': 
    t1 = Thread(target=add_num) 
    t2 = Thread(target=add_num) 
    t3 = Thread(target=add_num) 
    t3.start() 
    t1.start() 
    t2.start() 
    time.sleep(100)
可以看到是0 4 7三个核在负载，而且无法跑满，连50%都跑不到，但是34+37+40 = 111 这时就有个猜想，是否线程本质只占一个cpu

试试开一个线程，是可以跑满100的

两线程

相加为100%

三进程

可以看到是07 11 13三个核在负载，全部跑满100%

两线程C代码

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#include <stdio.h> 
#include <stdlib.h> 
#include <pthread.h> 
 
void print_message_function (void *ptr); 
 
int main() 
{ 
    int tmp1, tmp2; 
    void *retval; 
    pthread_t thread1, thread2; 
    char *message1 = "thread1"; 
    char *message2 = "thread2"; 
 
    int ret_thrd1, ret_thrd2; 
 
    ret_thrd1 = pthread_create(&thread1, NULL, (void *)&print_message_function, (void *) message1); 
    ret_thrd2 = pthread_create(&thread2, NULL, (void *)&print_message_function, (void *) message2); 
 
    // 线程创建成功，返回0,失败返回失败号 
    if (ret_thrd1 != 0) { 
        printf("线程1创建失败\n"); 
    } else { 
        printf("线程1创建成功\n"); 
    } 
 
    if (ret_thrd2 != 0) { 
        printf("线程2创建失败\n"); 
    } else { 
        printf("线程2创建成功\n"); 
    } 
 
    //同样，pthread_join的返回值成功为0 
    tmp1 = pthread_join(thread1, &retval); 
    printf("thread1 return value(retval) is %d\n", (int)retval); 
    printf("thread1 return value(tmp) is %d\n", tmp1); 
    if (tmp1 != 0) { 
        printf("cannot join with thread1\n"); 
    } 
    printf("thread1 end\n"); 
 
    tmp2 = pthread_join(thread1, &retval); 
    printf("thread2 return value(retval) is %d\n", (int)retval); 
    printf("thread2 return value(tmp) is %d\n", tmp1); 
    if (tmp2 != 0) { 
        printf("cannot join with thread2\n"); 
    } 
    printf("thread2 end\n"); 
 
} 
 
void print_message_function( void *ptr ) { 
    int i = 0; 
    while(1) 
    { 
        i++; 
    } 
}

C的多线程没有这个问题

​

现象：

python的线程只能用到一个核。

结论

个人查资料后的判断结论是：python用到了GIL锁导致python线程只能用到一个核
Reference :
https://timber.io/blog/multiprocessing-vs-multithreading-in-python-what-you-need-to-know/