Title: Class 12: Scheduling in Linux and Web Servers
Date: 2014-03-04
Category: Classes
Tags: operating systems, scheduling, Linux scheduler, healthcare.gov, web scheduling
Author: David Evans

   <div class="todo">
**[Problem Set 3](|filename|../../pages/ps/ps3/ps3.md)** is due by
  11:59pm on **Wednesday, 5 March**.  See the [previous announcement](|filename|../../announcements/ps3-signup.md) for details on how to submit PS3.
</div>

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<iframe src="http://www.slideshare.net/slideshow/embed_code/31905061" width="476" height="400" frameborder="0" marginwidth="0" marginheight="0" scrolling="no"></iframe><br>
[Videos](https://www.youtube.com/playlist?list=PLvpsxlEF9cP2vrwRWxzq2e0PXi0t_SQ67)
</center>

# PS3 Leaderboard Update

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<iframe width="640" height="360" src="//www.youtube-nocookie.com/embed/HKrVC7YK8pM?list=PLvpsxlEF9cP2vrwRWxzq2e0PXi0t_SQ67" frameborder="0" allowfullscreen></iframe>
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# Scheduling in Linux

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<iframe width="640" height="360" src="//www.youtube-nocookie.com/embed/oKKCG4MufwI?list=PLvpsxlEF9cP2vrwRWxzq2e0PXi0t_SQ67" frameborder="0" allowfullscreen></iframe>
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What were the problems with the Linux _O_(_N_) scheduler?

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What were the problems with the Linux _O_(1) scheduler?
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[Inside the Linux 2.6 Completely Fair Scheduler: Providing fair access to CPUs since 2.6.23](http://www.ibm.com/developerworks/linux/library/l-completely-fair-scheduler/)  
[CFS Scheduler Design](http://people.redhat.com/mingo/cfs-scheduler/sched-design-CFS.txt) and [Announcement](http://lwn.net/Articles/230501/)

What are the most important goals for an operating system scheduler today?
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[Energy Saving in OS 10.9 Mavericks](http://arstechnica.com/apple/2013/10/os-x-10-9/12/#energy-saving)
[How OS X "Mavericks" works its power-saving magic](http://arstechnica.com/apple/2013/06/how-os-x-mavericks-works-its-power-saving-magic/)

How does the Mac OS 10.9 Mavericks scheduler save energy?
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# Web Server Overload

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If the rate of incoming requests exceeds the server's rate of processing requests, what can you do?
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Why is it hard to solve problems by just throwing more resources at
them?

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When is horizontal partitioning better than vertical partitioning?
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How should a server respond to a distributed denial-of-service attack?
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What is (or should be?) the bottleneck resource for most web servers?
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[_Obama's Trauma Team_](|filename|./healthcaregov.html),
Time Magazine (cover article by Steven Brill), 10 March 2014. [Original](http://content.time.com/time/magazine/article/0,9171,2166770,00.html)


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