Enable / Disable SMT (HyperThreading)

Simultaneous multithreading (SMT) is a technique for improving the overall efficiency of superscalar CPUs with hardware multithreading.

# From https://docs.kernelcare.com/how-to/

# Check the SMT state
cat /sys/devices/system/cpu/smt/active

#Enable SMT
echo on > /sys/devices/system/cpu/smt/control

#Disable SMT
echo off > /sys/devices/system/cpu/smt/control

Tick-free CPU

When kernel is booted with nohz_full=1-127 set, CPU 1-127 are isolated. Refer CPU Isolation - Nohz_full - by SUSE Labs (part 3) | SUSE Communities for more details.

Also see:

A full list of kernel parameters is available at https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html.

Set kernel.yama.ptrace_scope to 0

For temporary applying, use the following command

sudo sysctl -w kernel.yama.ptrace_scope=0

For permanent, change /etc/sysctl.d/10-ptrace.conf.

For documentation, see The Linux kernel user’s and administrator’s guide » Linux Security Module Usage - Yama.