15-849 Assignment 2: PowerTOP

Assigned:: Sunday, Jan 25
Due: Wednesday, Feb 4th, 11:59pm

For this assignment,

  1. Install PowerTOP on your (Linux-running) computer, with whatever kernel modifications are necessary to get it to properly report stats
  2. Write a program that takes as parameters:

    and alternates between busy-waiting for active_seconds doing additions, and sleeping using nanosleep for the sleep duration. You will run this program with different sizes for each of these, with various values of active seconds and different ratios of sleep time. For example, active seconds = 10, sleep duration = 90 would represent a 10% busy workload with a granularity of 10 microseconds.

  3. Run this program, with active/sleep seconds that vary in order to create plots that show the percentage of time in each P-state and C-state as you vary the %age busy and the granularity of work:
  4. Record the average power used by your computer during each of these experiments. (Note that you can use the kill-a-watt to measure power over time, averaged). Plot the power used for the same experiments.

For questions and discussion about the assignment, please make use of the Assignment 2 Wiki Page. I've started this off with some discussion about measuring the sleep and active time of your busy-wait program.

Last updated: Sun Feb 08 13:13:23 -0500 2009 [validate xhtml]