Operating Systems Question Bank with Answers 02

List the advantages of system level (kernel level) threads in operating systems

Question:

List the advantages of system-level (kernel level) threads

Answer:

Following are the advantages of system level thread in OS;

• Each thread can be treated separately. Rather than using the time slice of one process over many threads. Should a process with 100 threads get 100 times the CPU time of a process with 1 thread?

• Because kernel has full knowledge of all threads, Scheduler may decide to give more time to a process having large number of threads than process having small number of threads.

• A thread blocking in the kernel doesn't stop all other threads in the same process. With the user-level threads if one thread blocks for IO the OS sees the process as blocked for IO. Hence, kernel-level threads are especially good for applications that frequently block.

• On a multiprocessor (including multi-core), different threads can be scheduled on different processors. This can only be done if the OS knows about the threads.

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