Fix #7: use intel_pstate/no_turbo to disable turboboost

uarch-bench.sh

@@ -4,41 +4,15 @@
 
 set -e
 
-# pass cpu # and get the state of the turbo mode, 0 is enabled, 1 is disabled
-function get_core_turbo_intel {
-	echo $(sudo rdmsr -p${core} 0x1a0 -f 38:38)
-}
-
-# get the turbo state of all cores as a string
-function get_turbo_state_string {
-	local turbo_state
-	for core in $cores; do
-    	turbo_state+="$(get_core_turbo_intel $core) "
-	done
-	echo $turbo_state
-}
-
-
-function is_even {
-  if [ $(( $1 % 2)) -eq 0 ]; then echo "O";
-  else echo "X";
-  fi
-}
-
 export VENDOR_ID=$(lscpu | grep 'Vendor ID' | egrep -o '[^ ]*$')
 export MODEL_NAME=$(lscpu | grep 'Model name' | sed -n 's/Model name:\s*\(.*\)$/\1/p')
 export SCALING_DRIVER=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver)
 export SCALING_GOVERNOR=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor)
+export NO_TURBO=$(cat /sys/devices/system/cpu/intel_pstate/no_turbo)
 
 echo "Driver: $SCALING_DRIVER, governor: $SCALING_GOVERNOR" 
 echo -e "Vendor ID: $VENDOR_ID\nModel name: $MODEL_NAME"
 
-################ Load the msr kernel module (needed by turbo-boost disabling code) ###########
-if [[ -z $(which rdmsr) ]]; then
-    echo "msr-tools is not installed. Run 'sudo apt-get install msr-tools' to install it." >&2
-    exit 1
-fi
-
 ############### Adjust the scaling governor to 'performance' to avoid sub-nominal clocking ##########
 
 if [[ "$SCALING_GOVERNOR" != "performance" ]]; then
@@ -57,17 +31,14 @@ lsmod | egrep -q "^msr " || { echo "loading msr kernel module"; sudo modprobe ms
 
 ################# Disable turbo boost #######################
 
-cores=$(cat /proc/cpuinfo | grep processor | awk '{print $3}')
-echo "setting turbo state for cores $(echo $cores | tr '\n' ' ')"
-
-original_state=$(get_turbo_state_string)
-echo "Original no_turbo state: $original_state"
-
-for core in $cores; do
-	sudo wrmsr -p${core} 0x1a0 0x4000850089
-done
-
-echo "Modified no_turbo state: $(get_turbo_state_string)"
+if [[ $NO_TURBO != 1 ]]; then
+	sudo sh -c "echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo"
+	if [[ $(cat /sys/devices/system/cpu/intel_pstate/no_turbo) == 1 ]]; then
+		echo "Succesfully disabled turbo boost";
+	else
+		echo "Failed to disable turbo boost";
+	fi
+fi
 
 ################ Load the libpfc kernel module if necessary ##################
 
@@ -82,17 +53,16 @@ fi
 
 ./uarch-bench "$@"
 
-orig_array=($original_state)
-i=0
-for core in $cores; do
-	orig_state=${orig_array[$i]}
-	if [[ $orig_state == "0" ]]; then
-		sudo wrmsr -p${core} 0x1a0 0x850089
+# restore the no_turbo if we changed it
+if [[ $NO_TURBO == 0 ]]; then
+	echo -n "Reverting no_turbo to $NO_TURBO: "
+	sudo sh -c "echo $NO_TURBO > /sys/devices/system/cpu/intel_pstate/no_turbo"
+	if [[ $(cat /sys/devices/system/cpu/intel_pstate/no_turbo) == 1 ]]; then
+		echo "Succesfully restored no_turbo state: $NO_TURBO";
+	else
+		echo "Failed to restore no_turbo state: $NO_TURBO";
 	fi
-	((i++))
-done
-
-echo "Restored no_turbo state: $(get_turbo_state_string)"
+fi
 
 # restore the cpu governor if we changed it
 if [[ $original_governor ]]; then