Term
| ______ is when you monitor a real system and record a sequence of actual events |
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Definition
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Term
| Kernel maintains a per-CPU _______ for all the runnable tasks |
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Definition
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Term
| It is called _____ when there is no time left, it is not run-able until all other tasks use their slices |
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Definition
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Term
| It is called _____ when tasks are run-able as long as there is time left in its time slice |
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Definition
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Term
| In windows scheduling, if no run-able thread, then the dispatcher will execute the ________ |
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Definition
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Term
| Multicore processor may complicate scheduling due to ________ |
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Definition
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Term
| The solution to processor affinity is: |
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Definition
soft affinity
hard affinity |
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Term
| ______ is a migrating process that is expensive to invalidate and repopulate cache |
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Definition
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Term
| _____ is when each processor is self-scheduling |
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Definition
| symmetric multiprocessing |
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Term
| _______ is when only one processor makes scheduling decisions I/O processing, an dother system activity |
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Definition
| asymmetric multiprocessing |
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Term
| Since CPU scheduling is -more complex when multiple CPUs are available, we assume processors are _____________ in functionality |
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Definition
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Term
| _____ schedules threads using SCS scheduling |
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Definition
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Term
| _____ schedules threads using PCS scheduling |
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Definition
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Term
| _______ is the API in Pthread scheduling |
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Definition
| ptbread_attr_set/getscope |
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Term
| _____ is the scheduling competition within the process |
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Definition
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Term
| ______ is the competition among all the threads in the system |
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Definition
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Term
| _______ is when each process gets a small amount of CPU time |
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Definition
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Term
| _______ will gradually increase the priority of processes that wait in the system for a long time |
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Definition
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Term
| _____ is a problem with priority scheduling algorithms because low priority processes may never execute |
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Definition
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Term
| The preemptive version of shortest-job-first-scheduling is called: |
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Definition
| shortest-remaining time first |
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Term
| ______ is all other processes waiting until the running CPU-bound process is done |
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Definition
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Term
| For interactive systems, minimize _____ in response time to optimize different values |
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Definition
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Term
| Under some circumstances, like in _______, the system optimizes _____ or _____ value |
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Definition
real time systems
minimum
maximum |
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Term
| In most cases, systems optimize ______ values |
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Definition
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Term
| _____ is the time it takes from when a request was submitted until the first response is produced |
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Definition
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Term
| _____ is the total time spent waiting in the ready queue |
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Definition
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Term
| _____ is the time to execute a particular process |
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Definition
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Term
| _____ is the number of processes that complete execution per time unit |
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Definition
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Term
| _____ is the percentage of CPU being busy |
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Definition
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Term
| ______ is the time it takes for the dispatcher to stop one process and start another running |
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Definition
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Term
| True/False The kernel is preemptive |
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Definition
| False, the kernel is nonpremptive |
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Term
| Another word for nonpreemptive is _______ |
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Definition
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Term
CPU scheduling decisions may take place when a process:
switches from running to waiting state (wait for I/O)
switches from running to ready state (when an interrupt occurs)
switches from waiting to ready (at completion of I/O)
terminates
Scheduling under condition ______ and _____ is non preemptive (non-rescheduling) |
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Definition
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Term
| Process execution alternates between _______ and ______ |
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Definition
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Term
| What is the difference between fork and clone? |
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Definition
With clone, the call allows the child process to share parts of its execution context with the calling process.
Main use of clone is to implement threads. |
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Term
| Process execution consists of a _____ of ________ and ______ |
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Definition
cycle
CPU execution
I/O wait |
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Term
| Maximum CPU utilization is obtained with ________ |
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Definition
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Term
| CPU scheduler selects another process when current one is in _____ |
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Definition
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Term
| CPU scheduler selects from among the processes in _______, and allocates CPU to one of them |
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Definition
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Term
| CPU scheduling decisions may take place when a process: |
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Definition
switches from running to waiting state (wait for I/O)
switches from running to ready state (when an interrupt occurs)
switches from waiting to ready (at completion of I/O)
terminates |
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Term
| Once the CPU has been allocated to a process, the process keeps it until it ______ or ______ |
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Definition
terminates
switching to the waiting state |
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Term
| Preemptive scheduling needs ______ such as a timer |
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Definition
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Term
| Kernel states will be inconsistent if _______ when updating shared data |
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Definition
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Term
| What are the solutions for using preemption since it affects the OS kernel design? |
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Definition
Waiting for either the system call to complete or the I/O block
Disable kernel preemption when updating shared data |
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Term
| The dispatcher module gives the control of the CPU to the process selected by the short-term scheduler by: |
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Definition
switching context
switching to user mode
jumping to the proper location in the user program to restart that program |
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Term
| Turnaround time happens from the time of _____ to the time of ______ |
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Definition
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Term
| Generally you maximize ______ and ____, and minimize _____, _____, and _____ for optimization |
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Definition
CPU utilization
throughput
turnaround time
waiting time
response time |
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Term
| The scheduling algorithms are: |
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Definition
FCFS (First Come First Served) Scheduling
SJF (Shortest Job First) Scheduling
Priority Scheduling
Round-robin Scheduling
Multilevel queue scheduling
Multilevel feedback queue scheduling |
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Term
| True/False FCFS Scheduling is preemptive |
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Definition
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Term
| How is SJF provably optimal? |
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Definition
It gives minimum average waiting time for a set of given processes
Moving a short process before a long one decreases the overall waiting time |
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Term
| True/False SJF Scheduling is preemptive |
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Definition
| BOTH. SJF is preemptive or nonpreemptive |
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Term
| True/False Priority scheduling is preemptive |
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Definition
| BOTH. Priority scheduling is preemptive or nonpreemptive |
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Term
| What happens in Round Robin when the q, time quantum, is too large? |
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Definition
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Term
| What happens in Round Robin when the q, time quantum, is too small? |
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Definition
| Then you context switch, which is high overhead |
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Term
| A timer interrupts every _____ to schedule the next process |
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Definition
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Term
| If there are n processes, each process gets ____ of the CPU time |
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Definition
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Term
| No process waits more than _____ time units |
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Definition
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Term
| With multi level queue, the ready queue is partitioned into _______ |
|
Definition
separate queues
Foreground (interactive) and background (batch) processes |
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Term
| With multilevel queue, processes are _____ assigned to a given queue |
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Definition
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Term
| With multilevel queue, each queue has its own ________ |
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Definition
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Term
| Multilevel queue is ______, where schedung must be done through the queues |
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Definition
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Term
| With fixed priority scheduling there is the possibility of ____ |
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Definition
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Term
| _______ is when each queue gets a certain amount of CPU time which it can schedule amongst its processes |
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Definition
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Term
| With multilevel queues a process can _____ between various queues |
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Definition
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Term
| Aging is implemented when |
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Definition
| a process can move between various queues |
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Term
| MLFQ schedules are defined by these parameters: |
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Definition
Minnie Pounded Ninjas Said Minature Mickey Mouse Socks
number of queues
scheduling algorithms for each queue
method used to determine when to assign a process a higher priority
method used to determine when to demote a process
method used to determine which queue a process will enter when that process needs service |
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Term
| MLFQ (Multilevel Feedback Queue) is the ______ CPU-scheduling algorithm |
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Definition
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Term
| CPU scheduling is _______ when multiple CPUs are available |
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Definition
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|
Term
| Which multiple-processor scheduling is used by common operating systems? |
|
Definition
| symmetric multiprocessing |
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Term
| Multicore processor has multiple processor cores on the _____ |
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Definition
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Term
| You ______ when you access memory, a process spends a significant amount of time waiting for data to become available |
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Definition
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Term
| The solution to multithreaded CPU core is to: |
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Definition
| share the exec unit, but duplicate architecture states like registers, for each CPU thread |
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Term
| _____ may undo good scheduling efforts in the host or guests |
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Definition
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Term
| ____ schedules multiple guests onto CPUs |
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Definition
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Term
| Each ____ does its own scheduling not knowing it is running on a virtual processor |
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Definition
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Term
|
Definition
| Trying to keep a process running on the same processor |
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Term
|
Definition
| The OS tries to keep a process running on the same processor, no guarantees |
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Term
|
Definition
| A process says, "I am not allowed to go to other processors" |
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