is it possible to implement a scheduling algorithm in kernel?

[punu]

hello,please help me with this,i have a project to do and want to is it possible to implement??please tell me anybody.. the link is comjnl.oxfordjournals.org/content/53/7/895.short.Implementing a Thermal-Aware Scheduler in Linux Kernel on a Multi-Core Processor
thank you

[white_hound]

Of course it is possible - it is implemented now, and you surely can intervene in the code.
In the kernel, the scheduler is implemented in sched.c - start there.
A few years back I did a project that dealt with scheduling policies.
As my first reference I used this paper:
"Understanding the Linux 2.6.8.1 CPU Scheduler", by Josh Aas.
It is slightly outdated, and kernel scheduler has changed from then, but hopefully you will be able to find newer articles ...
Good luck.

[punu]

hey thnx for the reply, I referred to the sched.c code but I am not getting where do I make changes..? I have a RR algorithm to implement as a new scheduler so that its performance can be compared with linux's baseline algo..I need some guidance on it..some kind of links will also be helpful. Thank you.

[white_hound]

Did you read the paper I referenced ?
There you will find the explanation of the concept of runqueue - a per-cpu queue of tasks ready to run. Now you schedule these tasks managing some metrics in order to provide everyone an amount of time it deserves.
There is no easy way. Read the paper, and start coding

[punu]

Did you read the paper I referenced ?
There you will find the explanation of the concept of runqueue - a per-cpu queue of tasks ready to run. Now you schedule these tasks managing some metrics in order to provide everyone an amount of time it deserves.
There is no easy way. Read the paper, and start coding

yes I did refer your paper link and it is a very good paper to understand the basics, after seeing my paper, the work I have to do is to add my temperature aware RR algorithm into the TIMER interrupt handler code...so that it will schedule/migrate the tasks according to the rise/fall in temperature of the core...can you tell me where can I find this timer interrupt handler code?

thnak you.

[white_hound]

scheduler_tick()

[punu]

hello again,for a while I have been trying to get the temperature of each core on processor(dual core)...but i am not getting how to exactly get it...means what code should i write in scheduler_tick()..in shorts what steps should i take to get the temperature of each core for process scheduling.
it would be very helpful to me..
thank you.

[white_hound]

There are hardware counters that gather CPU run time information. You could consult the code of lm-sensors driver, or possibly you could just use its data as input to your scheduling policy.