When should you use multithreading? And would multi threading be beneficial if the different threads execute mutually independent tasks?

Question

This were the only two questions I couldn\'t answer in the interview I got rejected from last night.

Answer 1

You should use multithreading when you want to perform heavy operations without "blocking" the flow.
Example in UIs where you do a heavy processing in a background thread but the UI is still active.

If the threads execute mutually exclusive tasks it is the best since there is no overhead for synchronization among threads needed

Answer 2

This article gives very good reasons: https://marcja.wordpress.com/2007/04/06/four-reasons-to-use-multithreading/

To summarize, the reasons are:

• Keep your program responsive.
• Make better use of your CPU. CPU may be blocked by IO or other stuff. While waiting, why not letting other threads use it
• Multiple threads can be scheduled to multiple CPU cores
• Some problems are naturally to be solved by multi-threading. Such solution can simplify your code.

Answer 3

You can use multithreading if the tasks can be broken down which can be executed in parallel. Like produce and consume , Validate and save , Read and Validate.

For the second question , Yes, it is beneficial for make a program into Multi threading if they are executing independent tasks.