Shell script to check which module(s) (or group of them) are responsible for high CPU load

drupal-performance-check

#!/bin/bash
# This script disables the Drupal modules one by one and checks CPU load
# after disabling each. Please run it from the Drupal root. Set the URL below.

url='http://localhost/drupal'

# Check CPU load on the last minute
function cpuload {
  uptime | sed 's/.*load average/CPU load on the last minute/g' | sed 's/,.*//g'
}

# Access the page 20 times and check the cpu load
function bulk_access {
  cpuload

  for i in {1..20}
  do
    wget -q $url -O /dev/null &
  done

  sleep 30
  
  cpuload

  # Number of on-going requests... for debugging only
  n=$(ps aux | grep wget | grep -v grep | wc -l)

  # Kill remaining requests
  killall -9 wget 2>/dev/null
}

# Make a first check before disabling any module
n=$(drush pm-list --type=Module --no-core --status=enabled --pipe | wc -l)
echo "CPU load with all modules $n enabled"
bulk_access
sleep 30

# Iterate through each enabled, no-core module
for module in $(drush pm-list --type=Module --no-core --status=enabled --pipe)
do

  echo '----------------------------------------------------------------------------------------------------'
  echo "Checking module $module"

  # Disable this module and its dependencies
  drush dis $module -y

  # Make one request just to rebuild Drupal cache
  wget -q $url -O /dev/null

  # Wait a little, just to let the CPU relax
  sleep 30

  bulk_access

  # Re-enable the module and its dependencies
  dependencies=$(drush pmi $module | grep 'Required by' -A 1000 | sed 's/.*://g' | sed ':a;N;$!ba;s/\s\+/ /g' | sed 's/,//g' | sed 's/^ //g')
  drush en $module $dependencies -y

  # Make one request just to rebuild cache
  wget -q $url -O /dev/null

done