gistfile1.rb

#!/usr/bin/env ruby

governors = ["performance", "ondemand"]

def setgov(gov, thread)
  `echo #{gov} > /sys/devices/system/cpu/cpu#{thread}/cpufreq/scaling_governor`
end

def showgov(thread)
  gov = `cat /sys/devices/system/cpu/cpu#{thread}/cpufreq/scaling_governor`.chomp
  puts "thread #{thread} is on #{gov}"
end

cores = 4
threads = 2
total = cores * threads


hot = 0

while true

  puts ""
  puts Time.now.to_s

  curcore = 0
  curthread = 0
  cores.times do
    threads.times do
      if curcore == hot
        setgov(governors.first, curthread)
      else
        setgov(governors.last, curthread)
      end
      showgov(curthread)
      curthread = curthread + 1
    end
    curcore = curcore + 1
  end
  hot = hot + 1
  sleep 6
  if hot == cores
    hot = 0
  end
end