Question 1 5.25 pts With preemptive scheduling it is possible to preempt a proce
ID: 3910994 • Letter: Q
Question
Question 1 5.25 pts With preemptive scheduling it is possible to preempt a process while executing a system call and in kernel mode? True False D Question 2 5.25 pts A task currently running from the default scheduling class on a Linux OS running the Completely Fair Scheduler will be preempted from the CPU when a task from the real-time scheduling class becomes runnable its age has increased and is moved to a lower priority queue its virtual runtime attribute becomes greater than the virtual runtime for another task that has just become runnablte its nice value is reduced by a negative (cD) increment D Question 3 5.25 pts The nice command on Linux and Unix can be used by non-root users to set a nice value for a process that is positive or 0, but only root (or users with the proper permission) can set a nice value that is negative. Which of the following explanations is the right one ? O Regular users can abuse the nice command and could assign a high priority (and more CPU time) to a process possibly in detriment to system tasks. O The nice value is an increment to the time slice for all other processes. If negative, it increases the response time for most processes on the OS, which can slow down the Ul and interactive applications O A negative nice value gives a process extended access rights to OS resources, equivalent to a switch to kernel mode. This is dangerous if available to regular users. O The nice field in the kemel task structure is unsigned int and cannot accept negative values.Explanation / Answer
Answer 1: False,
It isn't possible to preempt a process while executing a system call in kernel mode.
Kernel preemption method either monolithic or hybrid. If device driver can enter an infinite loop then increase the chance whole system crashing.
Answer 2:
A task currencly running from the the default scheduling class on a linux OS. Completely fair scheduler will be preempted from the cpu when a task from the real-time scheduling clasee becomes runnable
CFS cheduling policies mostly used in real-time : SCHED_NORMAL, SCHED_BATCH, and SCHED_IDLE.
For SCHED_RR and SCHED_FIFO policies because we can enable better scheduling and provide new features as a requested.
Answer 3:
Nice command on linux and unix can be used by non-root users to set a nice vaule for a process that is positive or 0. but only root can sets a nice value that is negative.
Regular users can abuse the nice command and could assign a high priority and more CPU time to a process possibly in detriment to system tasks
If you want nice values priority sortable value, then it's start with default is zero.
Positive priorities nice values are used for background tasks and that running when no other priority task is ready to run. and Negative priorities nice values cause a task running more frequently and sharing with available CPU time.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.