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Revision 3 as of 2015-03-07 16:56:17
KernelNewbies:
  • Preeti_U_Murthy

About Me

I am a Linux Kernel Developer working at IBM, Linux Technology Center, India. I work in the area of CPU Power Management, specifically enabling deep CPU Idle states and improving the CPU Frequency subsystem on IBM POWER platforms. I have been involved in the discussions around Power Aware Scheduling in the kernel community where we are trying to improve the power efficiency of the kernel. Of late I have been reviewing patches around Dynamic Ticks and am keenly interested in the Full Dynamic Ticks Infrastructure.

Project Details

References

  1. The chapter on "Time Management" at http://www.e-reading.link/bookreader.php/142109/Professional_Linux_kernel_architecture.pdf

  2. https://www.kernel.org/doc/Documentation/timers/NO_HZ.txt

  3. Status of Linux Dynamic Ticks: http://ertl.jp/~shinpei/conf/ospert13/slides/FredericWeisbecker.pdf

Tasks

The following tasks are listed in the increasing order of complexity:

To begin with, download the vanilla kernel.

Challenge Problem 1

Configure two different kernels, one with NO_HZ_IDLE=y and another with NO_HZ_IDLE=n. Boot each of these kernels and perform the following test on each.

Download the ebizzy benchmark from http://sourceforge.net/projects/ebizzy/. Compile and run this benchmark a few times. You must see consistent results. Record the number of records read. Download the powertop utility and run it while running the benchmark. Record the %time spent in different idle states.

Now compare the records read and %time spent in different idle states in both the above kernels and conclude as to which of the two has a better power efficiency.

Challenge Problem 2

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/dynticks-testing.git Clone this archive.

Run the test on two different kernels. Boot the first kernel, compiled with CONFIG_NO_HZ_IDLE = y in the config file, while boot the second kernel with CONFIG_NO_HZ_FULL = y.

This page will be updated with more tasks soon.

Contact Info

You can email me at: preeti@linux.vnet.ibm.com

My IRC handle is preeti

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