List reasons why a Mode switch between threads may be cheaper than a Mode switch between processes?

Answer

# 11. reason - the control blocks for processes are larger than for threads (hold more state information), so the amount of information to move during the thread switching is less than for process context switching 2. reason - the major reason is that the memory management is much simpler for threads than for processes. Threads share their memory so during mode switching, memory information does not have to be exchanged/changed, pages and page tables do not have to be switched, etc. This makes the thread context switch much cheaper than for processes. In case of processes the memory pieces (pages) need to be exchanged, etc. (Will talk about the details in few weeks). 3. reason - threads do not have to worry about accounting, etc, so do not have to fill out all the information about accounting and other process specific information in their thread control block, so keeping the thread control block consistent is much faster 4. reason - threads share files, so when mode switch happens in threads, these information stay the same and threads do not have to worry about it (similar to accounting information) and that makes the mode switch much faster.

answer 2## Process :Generally heavy weight by, the PCB holds kernel objects the values generally referred as state information. A application can be divided into two types in design phase: 1.Process - may affect application/program architecture 2.Threads - didn't affect architecture Threads typically are spawned for a short-term benefit where as process for long-term even the thread share its own process address space is never larger than 4GB. A single process may hold "n" threads so exchanging value between process; then the CPU spend most of its time for swapping it leads to thrasing definitely. Threads easily exchange their locale variables within its scope but exchange value between process stolen more CPU cycles.