print_flags()
{
  flags[1]="SD_LOAD_BALANCE:          Do load balancing on this domain"
  flags[2]="SD_BALANCE_NEWIDLE:       Balance when about to become idle"
  flags[4]="SD_BALANCE_EXEC:          Balance on exec"
  flags[8]="SD_BALANCE_FORK:          Balance on fork, clone"
  flags[16]="SD_WAKE_IDLE:             Wake to idle CPU on task wakeup"
  flags[32]="SD_WAKE_AFFINE:           Wake task to waking CPU"
  flags[64]="SD_WAKE_BALANCE:          Perform balancing at task wakeup"
  flags[128]="SD_SHARE_CPUPOWER:        Domain members share cpu power"
  flags[256]="SD_POWERSAVINGS_BALANCE:  Balance for power savings"
  flags[512]="SD_SHARE_PKG_RESOURCES:   Domain members share cpu pkg resources"
  flags[1024]="SD_SERIALIZE:             Only a single load balancing instance"
  flags[2048]="SD_WAKE_IDLE_FAR:         Gain latency sacrificing cache hit"

  DEC=$1

  echo "SD flag: $DEC"

  for ((mask=1;mask<2048;mask*=2)); do
   if [ "$[$mask & $DEC]" != "0" ]; then
      printf "+%4d: %s\n" $mask "${flags[$mask]}"
   else
      if [ $mask -le 64 ]; then
        printf "%c%4d: %s\n" "-" $mask "${flags[$mask]}"
      fi
   fi
  done
}

[ $# -lt "1" ] && {
  echo 'usage: tune-sched-domains <val>'
 
  VAL=$(cat /proc/sys/kernel/sched_domain/cpu0/domain0/flags)
  echo "current val on cpu0/domain0:"
  print_flags $VAL
  exit -1;
}

DOM0=$1
DOM1=${2:-$DOM0}
DOM2=${3:-$DOM1}
DOM3=${4:-$DOM2}

for CPU in /proc/sys/kernel/sched_domain/*; do
 for N in $CPU/*/flags; do

  VAL=`cat $N`
  case $N in
     "$CPU/domain0/flags") NEW_VAL=$DOM0 ;;
     "$CPU/domain1/flags") NEW_VAL=$DOM1 ;;
     "$CPU/domain2/flags") NEW_VAL=$DOM2 ;;
     "$CPU/domain3/flags") NEW_VAL=$DOM3 ;;
     *) echo "error!" ;;
  esac

  NEW_VAL=$1
  echo $NEW_VAL > $N

  [ "$CPU" = "/proc/sys/kernel/sched_domain/cpu0" ] && {
    echo "changed $N: $VAL => $NEW_VAL"
    print_flags $NEW_VAL
  }
 done
done