#!/bin/bash

HYPERTHREADING=1

function toggleHyperThreading() {
 for CPU in /sys/devices/system/cpu/cpu[0-9]*; do
   CPUID=`basename $CPU | cut -b4-`
   echo -en "CPU: $CPUID\t"
   [ -e $CPU/online ] && echo "1" > $CPU/online
   THREAD1=`cat $CPU/topology/thread_siblings_list | cut -f1 -d,`
   if [ $CPUID = $THREAD1 ]; then
     echo "-> enable"
     [ -e $CPU/online ] && echo "1" > $CPU/online
   else
    if [ "$HYPERTHREADING" -eq "0" ]; then echo "-> disabled"; else echo "-> enabled"; fi
     echo "$HYPERTHREADING" > $CPU/online
   fi
 done
}

function enabled() {
    echo -en "Enabling HyperThreading\n"
    HYPERTHREADING=1
    toggleHyperThreading
}

function disabled() {
    echo -en "Disabling HyperThreading\n"
    HYPERTHREADING=0
    toggleHyperThreading
}

#
ONLINE=$(cat /sys/devices/system/cpu/online)
OFFLINE=$(cat /sys/devices/system/cpu/offline)
echo "---------------------------------------------------"
echo -en "CPU's online: $ONLINE\t CPU's offline: $OFFLINE\n"
echo "---------------------------------------------------"
while true; do
  read -p "Type in e to enable or d disable hyperThreading or q to quit [e/d/q] " ed
  case $ed in
    [Ee]* ) enabled; break;;
    [Dd]* ) disabled;exit;;
    [Qq]* ) exit;;
    * ) echo "Please answer e for enable or d for disable hyperThreading.";;
  esac
done