Self Doubt:Operating System-Threads

Question

User level threads doesnot require context switching- This is a true statement (Because OS cannot recognize user level threads)

Can somebody elaborate more on it??

This given answer is wrong I think:https://gateoverflow.in/290648/made_easy_test_series

Plz check

Comments

User level thread does context switching.

Whether OS recognizes ULT or not why does it matter ?

ULT will do context switching to save time so that it can resume from the point at which it stopped the thread  and not to redo the processing again.

It is just that it does not requires hardware support so it is faster than kernel level threads.

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User level thread does context switching.

where u got it?? Any link?? 

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Read the answer again.

https://gateoverflow.in/290648/made_easy_test_series

Thus,User Level Thread Switching does not mandatorily require Context Switching

It also means that sometimes it does require context switching so S1 is false.

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yes, this question also supports that https://www.geeksforgeeks.org/gate-gate-cs-2014-set-1-question-30/

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@Satbir

I have read many artical, but not getting clearly "if user level threads requires context switching or not". Moreover not getting clear definition of user level thread, even not in 'Galvin'

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I have get idea of user level threads from here and here. But not getting whatever that ans is written

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see this line here

"Creating a new thread, switiching between threads, and synchronizing threads are done via procedure call. i.e no kernel involvement."

context switching is done with the help of procedure calls in ULT.

Operating Systems kernel provides system call to create and manage threads for KLT

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I also didn't understood much from that answer.