1 votes 1 votes Operating System operating-system threads + – sushmita asked Jan 5, 2017 sushmita 2.4k views answer comment Share Follow See all 11 Comments See all 11 11 Comments reply Kaushik.P.E commented Jan 5, 2017 reply Follow Share Is this in any way related to GATE? And yes they can be. 0 votes 0 votes sushmita commented Jan 5, 2017 reply Follow Share very well it relates to GATE in OS. My doubt is that user level threads are not known to kernel so will they be scheduled concurrently or not?? 1 votes 1 votes Kaushik.P.E commented Jan 5, 2017 reply Follow Share Is multiprocessor scheduling algorithms included in OS? 0 votes 0 votes Kaushik.P.E commented Jan 5, 2017 reply Follow Share hope my comment was not misunderstood. deviating now can turn out to be a very big blunder. 0 votes 0 votes sushmita commented Jan 5, 2017 reply Follow Share ???? meaning?? 0 votes 0 votes Kaushik.P.E commented Jan 5, 2017 reply Follow Share focus on the syllabus rather than deviating to unnecessary topics. 0 votes 0 votes sushmita commented Jan 5, 2017 reply Follow Share yeah u r right. well its in syllabus. threads in in syllabus right and such question was asked in some previous year gate too, From there only, this question came to my mind. 1 votes 1 votes Arjun commented Jan 6, 2017 reply Follow Share @Kaushik Have you seen previous year GATE questions? 1 votes 1 votes Kaushik.P.E commented Jan 6, 2017 reply Follow Share No arjun. If there are any previous year questions related to this please do share the links. –1 votes –1 votes sushmita commented Jan 6, 2017 reply Follow Share wow great. that much pain u can take urself. 1 votes 1 votes Kaushik.P.E commented Jan 6, 2017 reply Follow Share :-). 0 votes 0 votes Please log in or register to add a comment.
Best answer 10 votes 10 votes No, they cannot be. In fact they cannot be executed as multiple threads (SMT) on a single core also as for the kernel, it has no idea of user threads. Arjun answered Jan 6, 2017 • selected Jan 6, 2017 by sushmita Arjun comment Share Follow See all 7 Comments See all 7 7 Comments reply Show 4 previous comments Kaushik.P.E commented Jan 6, 2017 reply Follow Share And please elaborate on the difference between User thread and kernel thread. User threads make use of system calls to execute priviledge instructions. Will that spawn a new kernel thread? –1 votes –1 votes Shubhanshu commented May 1, 2017 reply Follow Share Arjun Sir, please explain why user-level threads can only be executed on a single processor only? 0 votes 0 votes Rupendra Choudhary commented Sep 16, 2017 reply Follow Share Hello Sir It's known that multithreading (user level thread) on multiprocessor is not beneficial as OS is unaware of the existence of user level threads but i'm doubtful about your comment like 'User level threads can't be even executed on uni-processor system' ? Can you elaborate your argument because as per my knowledge i don't find any problem about multiple user level threads execution. We can achieve scheduling between user level threads through user level libraries. I didn't do any research but i read it that some OS assign user level threads to kernel level processes for the purpose of scheduling. Tell me if i went wrong somewhere. 1 votes 1 votes Please log in or register to add a comment.
3 votes 3 votes Multiple user-level threads can run on different cores at the same time, IF they're running inside different kernel-level threads. If you only have ULT as a tool, you're limited to a single processor. If KLT are available, you can spread the kernel threads over multiple processors and dispatch your ULT among the available kernel threads reena_kandari answered Aug 1, 2017 reena_kandari comment Share Follow See all 2 Comments See all 2 2 Comments reply Abbas commented Jan 24, 2018 reply Follow Share yes...that we can say it's many to many mapping of multithreaded process 1 votes 1 votes 0xprateek commented May 14, 2022 reply Follow Share Explains everything. 0 votes 0 votes Please log in or register to add a comment.