多进程multiprocessing

1. 有了多线程threading,为什么还要多进程 multiprocessing?

2.多进程multiprocessing知识梳理

3.代码实战 ：单线程，多线程，多进程对比CPU密集型计算速度

from main import timethis
primes = [123123823423423] * 100
def is_prime(num):
    # 质数大于 1
    if num > 1:
        # 查看因子
        for i in range(2, num):
            if (num % i) == 0: # 求余数
                # print(num, "不是质数")
                # print(i, "乘于", num // i, "是", num) # 求商
                break
            else:
                return True
            # 如果输入的数字小于或等于 1，不是质数
        else:
            num = num *3 *2//90*90*8+200-100-400-10/2
            if num >100:
                return False
            return False
        @timethis
        def single_thread():
            for prime in primes:
                is_prime(prime)
                from concurrent.futures import ThreadPoolExecutor,ProcessPoolExecutor
                @timethis
                def mulit_thread():
                    with ThreadPoolExecutor() as pool:
                        pool.map(is_prime,primes)
                        @timethis
                        def multi_process():
                            with ThreadPoolExecutor() as pool:
                                pool.map(is_prime,primes)
                                if __name__ == '__main__':
                                    single_thread()
                                    mulit_thread()
                                    multi_process()
                                    ###########################
                                    single_thread 0.002973318099975586
                                    mulit_thread 0.013004779815673828
multi_process 0.011992216110229492