Python Concurrency for Senior Engineering Interviews/

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Quiz 1

Quiz 1

Test what you have learnt so far.

We'll cover the following...

Question # 1

Consider the snippet below:

def child_task(str_obj):
    print(str_obj.__hash__())

if __name__ == '__main__':
    str_obj = "Educative!"
    multiprocessing.set_start_method('fork')

    print(str_obj.__hash__())

    process1 = Process(target=child_task, args=(str_obj,))
    process1.start()

    process2 = Process(target=child_task, args=(str_obj,))
    process2.start()

    process1.join()
    process2.join()
Q

What will be the output of all the print statements?

A)

Exactly the same

B)

All are different

C)

They may be different

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from multiprocessing import Process, current_process
import multiprocessing
def child_task(str_obj):
    print(id(str_obj))
if __name__ == '__main__':
    str_obj = "Educative!"
    multiprocessing.set_start_method('fork')
    print(id(str_obj))
    process1 = Process(target=child_task, args=(str_obj,))
    process1.start()
    process2 = Process(target=child_task, args=(str_obj,))
    process2.start()
    process1.join()
    process2.join()

Question # 2

Consider the same code from the previous question and assume we change the start method from fork to spawn.

Q

Will the output of the print statements be same?

A)

Yes

B)

No

C)

Maybe

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from multiprocessing import Process, current_process
import multiprocessing
def child_task(str_obj):
    print(id(str_obj))
if __name__ == '__main__':
    str_obj = "Educative!"
    multiprocessing.set_start_method('spawn')
    print(id(str_obj))
    process1 = Process(target=child_task, args=(str_obj,))
    process1.start()
    process2 = Process(target=child_task, args=(str_obj,))
    process2.start()
    process1.join()
    process2.join()

Observe that if the start method is changed to forkserver then the id for str_obj variable will be the same ...