DIR=/proc/sys/kernel/sched_domain/

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"
  flags[4096]="SD_PREFER_SIBLING:        Prefer to place tasks in a sibling domain"

  DEC=$1
  CPU=$2
  DOM=$3

  [ -d $DIR/$CPU/$DOM ] || { exit 0; }

  NAME=$(cat $DIR/$CPU/$DOM/name)

  [ $DEC = "-1" ] && DEC=$(cat $DIR/$CPU/$DOM/flags)

  echo "{$CPU/$DOM:$NAME} SD flag: $DEC"

  for ((mask=1;mask<=4096;mask*=2)); do
   if [ "$[$mask & $DEC]" != "0" ]; then
      printf "+%4d: %s\n" $mask "${flags[$mask]}"
   else
      if [ $mask -le 4096 ]; then
        printf "%c%4d: %s\n" "-" $mask "${flags[$mask]}"
      fi
   fi
  done
}


[ $# -lt "1" ] && {
  echo 'usage: tune-sched-domains <val>'

  print_flags -1 cpu0 domain0
  print_flags -1 cpu0 domain1
  print_flags -1 cpu0 domain2
  print_flags -1 cpu0 domain3

  exit -1;
}

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

cd $DIR

for CPU in *; do
 cd $CPU
 for DOM in *; do

  FLAGS=$DOM/flags

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

  echo $NEW_VAL > $FLAGS

  [ "$CPU" = "cpu0" ] && {
    echo "changed $FLAGS: $VAL => $NEW_VAL"
    print_flags $NEW_VAL $CPU $DOM
  }
 done
 cd ..
done