#!/bin/bash

set -x

# Load Variables
source "/etc/libvirt/hooks/kvm.conf"

# Calculate number of hugepages to allocate from memory (in MB)
HUGEPAGES="$(($MEMORY/$(($(grep Hugepagesize /proc/meminfo | awk '{print $2}')/1024))))"

echo "Allocating hugepages..."
echo $HUGEPAGES > /proc/sys/vm/nr_hugepages
ALLOC_PAGES=$(cat /proc/sys/vm/nr_hugepages)

TRIES=0
while (( $ALLOC_PAGES != $HUGEPAGES && $TRIES < 1000 ))
do
    echo 1 > /proc/sys/vm/compact_memory            ## defrag ram
    echo $HUGEPAGES > /proc/sys/vm/nr_hugepages
    ALLOC_PAGES=$(cat /proc/sys/vm/nr_hugepages)
    echo "Succesfully allocated $ALLOC_PAGES / $HUGEPAGES"
    let TRIES+=1
done

if [ "$ALLOC_PAGES" -ne "$HUGEPAGES" ]
then
    echo "Not able to allocate all hugepages. Reverting..."
    echo 0 > /proc/sys/vm/nr_hugepages
    exit 1
fi

# Enable CPU governor performance mode
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
for file in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do echo "performance" > $file; done
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

# Isolate host
systemctl set-property --runtime -- user.slice AllowedCPUs=14,15
systemctl set-property --runtime -- system.slice AllowedCPUs=14,15
systemctl set-property --runtime -- init.scope AllowedCPUs=14,15