In modern computers many processes run at once. Active processes are placed in an array called a run queue, or runqueue. The run queue may contain priority values for each process, which will be used by the scheduler to determine which process to run next. To ensure each program has a fair share of resources, each one is run for some time period (quantum) before it is paused and placed back into the run queue. When a program is stopped to let another run, the program with the highest priority in the run queue is then allowed to execute. Processes are also removed from the run queue when they ask to sleep, are waiting on a resource to become available, or have been terminated. In the Linux operating system (prior to kernel 2.6.23), each CPU in the system is given a run queue, which maintains both an active and expired array of processes. Each array contains 140 (one for each priority level) pointers to doubly linked lists, which in turn reference all processes with the given priority. The scheduler selects the next process from the active array with highest priority. When a process' quantum expires, it is placed into the expired array with some priority. When the active array contains no more processes, the scheduler swaps the active and expired arrays, hence the name O(1) scheduler. In UNIX or Linux, the sar command is used to check the run queue. The vmstat UNIX or Linux command can also be used to determine the number of processes that are queued to run or waiting to run. These appear in the 'r' column. There are two models for Run queues: one that assigns a Run Queue to each physical processor, and the other has only one Run Queue in the system (Wikipedia).
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From playlist Queue data structure playlist
Queuing lesson 1 - Types of queues, definitions
Hi all. In this lesson on queueing we introduce you to FIFO, LIFO, Single queue single server, single queue multiple server, multiple queue single server, multiple queue multiple server, baulking, reneging, and jockeying. A lot of definitions in one video - hope it helps!
From playlist Maths A / General Course, Grade 11/12, High School, Queensland, Australia
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From playlist Queue data structure playlist
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in this tutorial, I cover the basic concepts of queue and explain java implementation of queue.
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Live Stream: Process control in C
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From playlist Queue data structure playlist
0132 [ C++ ] Moderation queue for a multi-player game server
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From playlist Excalibur
RubyConf 2022: What does "high priority" mean? The secret to happy queues by Daniel Magliola
Like most web applications, you run important jobs in the background. And today, some of your urgent jobs are running late. Again. No matter how many changes you make to how you enqueue and run your jobs, the problem keeps happening. The good news is you're not alone. Most teams struggle w
From playlist RubyConf 2022: Mini and Houston
Writing an OS in Rust - Part 12e - A Better Executor
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Kernel Recipes 2015 - Solving the Linux storage scalability bottlenecks - by Jens Axboe
Flash devices introduced a sudden shift in the performance profile of direct attached storage. With IOPS rates orders of magnitude higher than rotating storage, it became clear that Linux needed a re-design of its storage stack to properly support and get the most out of these new devices.
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RubyConf 2021 - Parallel testing with Ractors - Putting CPU's to work by Vinicius Stock
Parallelizing tests is an opportune way of reducing the total runtime for a test suite. Rails achieves this by forking multiple separate workers that fetch tests from a queue. In Ruby 3, Ractors introduced new mechanisms for executing code in parallel. Can they be leveraged by a test frame
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Queues & Priority Queues - Beau teaches JavaScript
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From playlist Data Structures and Algorithms - Beau teaches JavaScript
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From playlist Software Development Lectures
Game Programming Patterns part 17.1 - (Reading, JS) Event Queue
We read through the Event Queue chapter of the Game Programming Patterns book and translate the code examples to JavaScript. Links code - https://github.com/brooks-builds/learning_game_design_patterns twitter - https://twitter.com/brooks_patton book - http://gameprogrammingpatterns.ocm/
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From playlist MIT 6.00SC Introduction to Computer Science and Programming
MIT 6.006 Introduction to Algorithms, Spring 2020 Instructor: Jason Ku View the complete course: https://ocw.mit.edu/6-006S20 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP63EdVPNLG3ToM6LaEUuStEY This class discusses a fourth weighted single-source shortest path algor
From playlist MIT 6.006 Introduction to Algorithms, Spring 2020
RailsConf 2016 - Inside ActiveJob By Jerry D'Antonio
ActiveJob made a huge impact when it landed Rails 4.2. Most job processors support it and many developers use it. But few ever need to dig into the internals. How exactly does ActiveJob allow us to execute performant, thread-safe, asynchronous jobs in a language not known for concurrency?
From playlist RailsConf 2016