Processor scheduling algorithms
Two-level scheduling is a computer science term to describe a method to more efficiently perform process scheduling that involves processes. Consider this problem: A system contains 50 running processes all with equal priority. However, the system's memory can only hold 10 processes in memory simultaneously. Therefore, there will always be 40 processes swapped out written on virtual memory on the hard disk. The time taken to swap out and swap in a process is 50 ms respectively. With straightforward Round-robin scheduling, every time a context switch occurs, a process would need to be swapped in (because only the 10 least recently used processes are swapped in). Choosing randomly among the processes would diminish the probability to 80% (40/50). If that occurs, then obviously a process also need to be swapped out. Swapping in and out of is costly, and the scheduler would waste much of its time doing unneeded swaps. That is where two-level scheduling enters the picture. It uses two different schedulers, one lower-level scheduler which can only select among those processes in memory to run. That scheduler could be a Round-robin scheduler. The other scheduler is the higher-level scheduler whose only concern is to swap in and swap out processes from memory. It does its scheduling much less often than the lower-level scheduler since swapping takes so much time. Thus, the higher-level scheduler selects among those processes in memory that have run for a long time and swaps them out. They are replaced with processes on disk that have not run for a long time. Exactly how it selects processes is up to the implementation of the higher-level scheduler. A compromise has to be made involving the following variables: * Response time: A process should not be swapped out for too long. Then some other process (or the user) will have to wait needlessly long. If this variable is not considered resource starvation may occur and a process may not complete at all. * Size of the process: Larger processes must be subject to fewer swaps than smaller ones because they take longer time to swap. Because they are larger, fewer processes can share the memory with the process. * Priority: The higher the priority of the process, the longer it should stay in memory so that it completes faster. (Wikipedia).
An animation showing the main features of a process scheduling system including the ready queue, blocked queue, high level scheduler and low level scheduler. It explains the principle of a round robin scheduling algorithm.
From playlist Operating Systems
Scheduling: The List Processing Algorithm Part 1
This lesson explains and provides an example of the list processing algorithm to make a schedule given a priority list. Site: http://mathispower4u.com
From playlist Scheduling
This lesson introduces the topic of scheduling and define basic scheduling vocabulary. Site: http://mathispower4u.com
From playlist Scheduling
Scheduling: The List Processing Algorithm Part 2
This lesson explains and provides an example of the list processing algorithm to create a digraph and make a schedule. Site: http://mathispower4u.com
From playlist Scheduling
Scheduling: The Decreasing Time Algorithm
This lesson explains how to use the decreasing time algorithm to create a priority list and then a schedule. Site: http://mathispower4u.com
From playlist Scheduling
A10 Example problem of multiplicity three
An example problem of multiplicity three.
From playlist A Second Course in Differential Equations
Into to the Mathematics of Scheduling
Terminology explained includes preference schedule, digraphs, tasks, arcs, processors, and timelines.
From playlist Discrete Math
Mathematics of Scheduling Part 2 of 2 Critical Time Algorithm
Use the Critical Time Algorithm to create efficient project schedules, and compare to the decreasing time algorithm.
From playlist Discrete Math
Creating Priority Lists and Timelines (Decreasing Time Algorithm)
In this video the decreasing time algorithm is used to create a priority list and generate a timeline.
From playlist Discrete Math
PMP Training Videos | Lesson 6: Project Time Management | Simplilearn
Time management is another key aspect of managing a project. As such, it is considered to be a core knowledge area, and is closely knit to scope and cost areas. The main purpose of this knowledge area, as it name suggests, is to build processes and outputs into the project that assist the
From playlist PMP Training Videos [2022 Updated]
Project Time Management | Project Schedule Management | PMP® Certification Training | Edureka
( PMP® Training: https://www.edureka.co/pmp-certification-exam-training ) This Edureka tutorial on Project Schedule Management will give you an insight into the various process and activities covered in to maintain and manage the schedule of a project. Project Schedule Management Schedule
From playlist PMP Certification Training Videos
MIT 6.042J Mathematics for Computer Science, Spring 2015 View the complete course: http://ocw.mit.edu/6-042JS15 Instructor: Albert R. Meyer License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 6.042J Mathematics for Computer Science, Spring 2015
MIT 1.258J Public Transportation Systems, Spring 2017 Instructor: Nigel Wilson, Gabriel Sanchez-Martinez, Neema Nassir View the complete course: https://ocw.mit.edu/1-258JS17 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP62AU7iNniqVoMl8C64tIOVk This lecture introduced
From playlist MIT 1.258J Public Transportation Systems, Spring 2017
MIT 1.258J Public Transportation Systems, Spring 2017 Instructor: Nigel Wilson, Gabriel Sanchez-Martinez, Neema Nassir View the complete course: https://ocw.mit.edu/1-258JS17 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP62AU7iNniqVoMl8C64tIOVk This lecture introduced
From playlist MIT 1.258J Public Transportation Systems, Spring 2017
🔥Project Management Full Course 2022 | Project Management Tutorial | Project Management| Simplilearn
🔥Post Graduate Program In Project Management: https://www.simplilearn.com/pgp-project-management-certification-training-course?utm_campaign=ProjectManagementFC30sept2022-pc9nvBsXsuM&utm_medium=DescriptionFirstFold&utm_source=youtube 🔥 PMP Certification Course: https://www.simplilearn.com/p
From playlist Simplilearn Live
Stanford Seminar - A Superscalar Out-of-Order x86 Soft Processor for FPGA
Henry Wong University of Toronto, Intel June 5, 2019 Although FPGAs continue to grow in capacity, FPGA-based soft processors have grown little because of the difficulty of achieving higher performance in exchange for area. Superscalar out-of-order processor microarchitectures have been us
From playlist Stanford EE380-Colloquium on Computer Systems - Seminar Series
PMP® Certification Full Course In 9 Hours | PMP® Training Videos | PMP® Course | Simplilearn
🔥Post Graduate Program In Project Management: https://www.simplilearn.com/pgp-project-management-certification-training-course?utm_campaign=ProjectManagement-1gP839Y3sJQ&utm_medium=Descriptionff&utm_source=youtube 🔥 PMP Certification Course: https://www.simplilearn.com/project-management/p
From playlist PMP Tutorial For Beginners | PMP Tutorial [2022 Updated]
The Step Response | Control Systems in Practice
Check out the other videos in this series: https://www.youtube.com/playlist?list=PLn8PRpmsu08pFBqgd_6Bi7msgkWFKL33b This video covers a few interesting things about the step response. We’ll look at what a step response is and some of the ways it can be used to specify design requirements f
From playlist Control Systems in Practice
PMP® Certification Full Course In 9 Hours | PMP® Training Videos | PMP® Course | Simplilearn
In this video on PMP Certification Full Course, we'll be covering a number of different concepts like project management, project planning, project time, cost quality and communication management, projct manager roles, interview questions and much more. With this course, you'll have every
From playlist PMP Tutorial For Beginners | PMP Tutorial [2022 Updated]