Thread

Question

Q:which of the following can run in parallel on different processors in a multiprocessors

a)user level thread 

b)kernel level thread 

c)processes

d) processes and kernel level thread

Answer 1

• Assigning anything to different processors is done by kernel.
• user-level threads are not known to the kernel.
• So  purely user-level threads cannot run in parallel on different processors in a multiprocessors.
• But Kernel-level threads can run simultaneously on multiprocessor machines.
• Processes can run simultaneously on multiprocessor machines.

answer is D

Comments

@shiva

one doubt..for kernel level threads we have a single address space then how multiple threads will run??

i want to know that we assign different address space for different processes or threads?

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@sh!va

This is what an nptel lecture says :

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Multi-threaded applications cannot take advantage of multiprocessing.

I think...

In the the picture shown above .. they mean to say "Kernel level thread"

Answer 2

First of all user level thread is unknown for kernel so it is obviously not run .Only kernel level thread and process can run parallel with different processor in multiprogramming.

So,D is the answer.