Disable hyper threading on ubuntu or Debian

I tested a few different ways and to disable hyper threading and this is what I landed on

Tested on ubuntu 18.04 and debain 9

Non persistent

echo off > /sys/devices/system/cpu/smt/control

To make it presistant

  • make a /etc/rc.local file
  • make it executable chmod +x /etc/rc.local
  • add the following echo off > /sys/devices/system/cpu/smt/control

Here is the Copy Pasta Verson

This copy pasta verson disables hyper threading while running and after roboot

if [[ ! -e /etc/rc.local ]]
then
 touch /etc/rc.local
 chmod +x /etc/rc.local
 cat <<'EOF' > /etc/rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# added to disable hyper threading
echo off > /sys/devices/system/cpu/smt/control
exit 0
EOF
else
 echo "Looks like you already have an rc.local file add the following before exit 0"
 echo "echo "echo off > /sys/devices/system/cpu/smt/control"
fi

echo off > /sys/devices/system/cpu/smt/control