From 530ca6825b0df322ad979497d55ecf3902e115ed Mon Sep 17 00:00:00 2001
From: Michael Vasseur <14887731+vmcj@users.noreply.github.com>
Date: Wed, 30 Jul 2025 18:45:26 +0200
Subject: [PATCH 1/5] Store disabled CPUs

We will use those later for a report and to not duplicate the method of disabling.
---
 provision-contest/disable-turboboost_ht | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/provision-contest/disable-turboboost_ht b/provision-contest/disable-turboboost_ht
index ce41e815..07f6d792 100755
--- a/provision-contest/disable-turboboost_ht
+++ b/provision-contest/disable-turboboost_ht
@@ -4,6 +4,13 @@ set -eu -o pipefail
 shopt -s extglob
 
 declare -A core_ids
+declare -a disabled_cores
+
+disable_cpu () {
+  cpu="$1"
+  echo 0 > $cpu/online
+  disabled_cores+=("${cpu##*/}")
+}
 
 # shellcheck disable=SC2012
 for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
@@ -41,7 +48,7 @@ for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
     # 'delimiter'.
     core_id=$(cat $cpu/topology/core_id | tr -d '\n')'-'$(cat $cpu/topology/physical_package_id | tr -d '\n')
     if [[ ${core_ids[$core_id]:-} ]]; then
-        echo 0 > $cpu/online
+        disable_cpu $cpu
     else
         core_ids[$core_id]=1
     fi

From 8ce7ab7ab3ce6727e5d12818d07c54ddc2bdcacf Mon Sep 17 00:00:00 2001
From: Michael Vasseur <14887731+vmcj@users.noreply.github.com>
Date: Wed, 30 Jul 2025 19:13:44 +0200
Subject: [PATCH 2/5] Store the isolated cores for ansible

This is defence in depth by disallowing the kernel to schedule work on the online cpu's before the script disables the CPU's. The script can fail when the CPU taken down is currently working on something.
---
 provision-contest/disable-turboboost_ht | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/provision-contest/disable-turboboost_ht b/provision-contest/disable-turboboost_ht
index 07f6d792..1d6739b5 100755
--- a/provision-contest/disable-turboboost_ht
+++ b/provision-contest/disable-turboboost_ht
@@ -12,6 +12,8 @@ disable_cpu () {
   disabled_cores+=("${cpu##*/}")
 }
 
+store_isolcpus_fact="/var/tmp/isolcpus"
+
 # shellcheck disable=SC2012
 for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
     [[ $(basename $cpu) =~ ^cpu[0-9]+$ ]] || continue
@@ -54,6 +56,11 @@ for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
     fi
 done
 
+if [ -n "${store_isolcpus_fact}" ]; then
+  csv_string=$(IFS=, ; echo "${disabled_cores[*]}")
+  echo "$csv_string" > "$store_isolcpus_fact"
+fi
+
 DIR_INTEL=/sys/devices/system/cpu/intel_pstate
 DIR_AMD=/sys/devices/system/cpu/cpufreq
 if [ -d $DIR_INTEL ]; then

From f95bb4c7758dd33fb79f151368ab4992166300b1 Mon Sep 17 00:00:00 2001
From: Michael Vasseur <14887731+vmcj@users.noreply.github.com>
Date: Wed, 30 Jul 2025 18:55:32 +0200
Subject: [PATCH 3/5] Clarify the package/socket usage

Package is more correct but socket is better known.

Also fixed a typo.
---
 provision-contest/disable-turboboost_ht | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/provision-contest/disable-turboboost_ht b/provision-contest/disable-turboboost_ht
index 1d6739b5..f077ee5c 100755
--- a/provision-contest/disable-turboboost_ht
+++ b/provision-contest/disable-turboboost_ht
@@ -41,10 +41,10 @@ for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
         chmod a-w $cpu/cpufreq/scaling_{max,min}_freq
     fi
 
-    # Disable all but one thread on each core. Both core_id and physical_package_id are
-    # numbers it must be ensured that for the following examples are seen as distinct:
+    # Disable all but one thread on each core per socket. Both core_id and physical_package_id
+    # are numbers so it must be ensured that for the following examples are seen as distinct:
     #  - core_id=1,  physical_package=11
-    #  - core_id=11, physycal_package=1
+    #  - core_id=11, physical_package=1
     # Simple concatenation would result in the string '111' for both cores. Though `cat`
     # adds a newline after each file, we do not want to rely on `cat` to always add this
     # 'delimiter'.

From 658a63ea9c0bbff7440e4efb8373bb499fd7cc4f Mon Sep 17 00:00:00 2001
From: Michael Vasseur <14887731+vmcj@users.noreply.github.com>
Date: Tue, 29 Jul 2025 22:14:33 +0200
Subject: [PATCH 4/5] Consider ARM processors

The boost exists for asahi@M1 laptops but not on a raspberry with ARMv7.
---
 provision-contest/disable-turboboost_ht | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/provision-contest/disable-turboboost_ht b/provision-contest/disable-turboboost_ht
index f077ee5c..ef535ee1 100755
--- a/provision-contest/disable-turboboost_ht
+++ b/provision-contest/disable-turboboost_ht
@@ -63,6 +63,8 @@ fi
 
 DIR_INTEL=/sys/devices/system/cpu/intel_pstate
 DIR_AMD=/sys/devices/system/cpu/cpufreq
+# Same for some ARM CPUs
+FILE_AMD=$DIR_AMD/boost
 if [ -d $DIR_INTEL ]; then
     # now disable turbo boost
     FILE=$DIR_INTEL/no_turbo
@@ -75,11 +77,10 @@ if [ -d $DIR_INTEL ]; then
     # increase freq from powersaving to normal, but don't overclock
     echo 100 > $DIR_INTEL/min_perf_pct
     echo 100 > $DIR_INTEL/max_perf_pct
-elif [ -d $DIR_AMD ]; then
+elif [ -f $FILE_AMD ]; then
     # now disable boosting
-    FILE=$DIR_AMD/boost
-    echo -n 0 > $FILE || echo "Could not write to '$FILE', ignoring for now..."
-    if [ $(cat $FILE) -ne 0 ]; then
+    echo -n 0 > $FILE_AMD || echo "Could not write to '$FILE_AMD', ignoring for now..."
+    if [ $(cat $FILE_AMD) -ne 0 ]; then
         echo "Error: turboboost still enabled!"
         exit 1
     fi

From 1eb5b513907f0d25bdac5828a39772d5144aa35e Mon Sep 17 00:00:00 2001
From: Michael Vasseur <14887731+vmcj@users.noreply.github.com>
Date: Tue, 29 Jul 2025 21:40:06 +0200
Subject: [PATCH 5/5] Disable efficiency cores

Also clarified the package/socket as package is more correct but socket is better known and fixed a typo.
---
 provision-contest/disable-turboboost_ht | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/provision-contest/disable-turboboost_ht b/provision-contest/disable-turboboost_ht
index ef535ee1..bca9112c 100755
--- a/provision-contest/disable-turboboost_ht
+++ b/provision-contest/disable-turboboost_ht
@@ -14,6 +14,14 @@ disable_cpu () {
 
 store_isolcpus_fact="/var/tmp/isolcpus"
 
+# Learn all efficency cores if they exist
+cpu_list=()
+if [ -f /sys/devices/cpu_atom/cpus ]; then
+  range="$(cat /sys/devices/cpu_atom/cpus)"
+  IFS='-' read -r start end <<< "$range"
+  cpu_list=($(eval echo {$start..$end}))
+fi
+
 # shellcheck disable=SC2012
 for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
     [[ $(basename $cpu) =~ ^cpu[0-9]+$ ]] || continue
@@ -49,6 +57,20 @@ for cpu in $(ls -1d /sys/devices/system/cpu/cpu* | sort --version-sort) ; do
     # adds a newline after each file, we do not want to rely on `cat` to always add this
     # 'delimiter'.
     core_id=$(cat $cpu/topology/core_id | tr -d '\n')'-'$(cat $cpu/topology/physical_package_id | tr -d '\n')
+
+    # Disable all efficiency cores
+    found=0
+    for efficiency_core in "${cpu_list[@]}"; do
+      if [[ "$cpu" == "/sys/devices/system/cpu/cpu$efficiency_core" ]]; then
+        disable_cpu $cpu
+        found=1
+        break
+      fi
+    done
+    if [ "$found" -eq "1" ]; then
+      continue
+    fi
+
     if [[ ${core_ids[$core_id]:-} ]]; then
         disable_cpu $cpu
     else