multithreaded programming

1. What are the benefits of multithreaded programming?

The benefits of multithreaded programming can be broken down into four major categories:

•  Responsiveness

•  Resource sharing

•  Economy

•  Utilization of multiprocessor architectures

2.Compare user threads and kernel threads.

User threads

User threads are supported above the kernel and are implemented by a thread library at the user level. Thread creation & scheduling are done in the user space, without kernel intervention. Therefore they are fast to create and manage blocking system call will cause the entire process to block

Kernel threads

Kernel threads are supported directly by the operating system .Thread creation, scheduling and management are done by the operating system. Therefore they are slower to create & manage compared to user threads. If the thread performs a blocking system call, the kernel can schedule another thread in the application for execution.

3.What is the use of fork and exec system calls?

Fork is a system call by which a new process is created.Exec is also a system call, which is used after a fork by one of the two processes to place the process memory space with a new program.

4.Define thread cancellation & target thread.

The thread cancellation is the task of terminating a thread before it has completed. A thread that is to be cancelled is often referred to as the target thread.For example, if multiple threads are concurrently searching through a database and one thread returns the result, the remaining threads might be cancelled.

5.What are the different ways in which a thread can be cancelled?

Cancellation of a target thread may occur in two different scenarios:

•  Asynchronous cancellation: One thread immediately terminates the target thread is called asynchronous cancellation.

•   Deferred cancellation: The target thread can periodically check if it should terminate, allowing the target thread an opportunity to terminate itself in an orderly fashion.