问题
What scheduling algorithms does Linux kernel use?
Where can I get more info about linux's kernel? (OS first course... student level)
回答1:
The linux kernel has several different available scheduling algorithms both for the process scheduling and for I/O scheduling. Download it from www.kernel.org and call
make menuconfig
You will get a full list of all available options with a built-in help. One guy that once came up with his O(1) scheduler is Con Kolivas. Definitively have to have a look at what he did. I was once a great break-through.
回答2:
If you just want to check what scheduler your linux system is using and which are available you can run the following command:
cat /sys/block/sda/queue/scheduler
The one between the [] is the one it's using at the moment. The other ones are available. To change it:
sudo bash -c 'echo deadline > /sys/block/sda/queue/scheduler'
Be carefull to set it back to default though, unless you know what you are doing and want.
Default (in newer Ubuntu distros at least) is CFQ (Completely Fair Scheduling):
http://en.wikipedia.org/wiki/CFQ
Interview with the creator (Jens Axboe):
http://kerneltrap.org/node/7637
回答3:
As others have already mentioned, there are several scheduling algorithms available, according to the intended use.
Check this article if you want to learn more about scheduling in Linux.
回答4:
i believe "completely fair scheduler" is in use with latest kernels. I think you can good amount of information if you just search for it in google.
link : http://en.wikipedia.org/wiki/Completely_Fair_Scheduler
回答5:
A new addition to Linux Kernel is EDF (Earliest Deadline First) for guaranteed RealTime support http://lkml.org/lkml/2009/9/22/186 http://www.evidence.eu.com/content/view/313/390/
回答6:
I think the Linux kernel actually has a few different schedulers you can choose from at compile-time. To find out more about the Linux kernel, you can download the kernel source code (or browse it online) and look in the Documentation directory. For example, the scheduler subdirectory might be helpful. You can also just look at the code itself, obviously.
回答7:
Linux Kernel allows three different scheduling algorithms mainly
- shortest job first
- Round Robin Scheduling
- Priority based preemptive scheduling algorithm.
The third scheduling method which it differs with lower version of Linux versions such as 2.4
回答8:
Modern GNU/Linux distributions use CFS (Completely Fair Scheduler). You may read more on that in the 4th chapter of this book: Linux Kernel Development 3rd Edition by Robert Love
You will find many interesting and easy to understand explanations there. I enjoyed a lot.
来源：https://stackoverflow.com/questions/1603341/what-scheduling-algorithms-does-linux-kernel-use